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Purpose: To present a set of closed‐form analytical equations to create a consistent eye model balance based on clinically measured input parameters in a single step. These models complement the existing iterative approaches in the literature. Methods: Two different approaches are presented, both considering the cornea and lens as equivalent thin lenses. The first, called the Gaussian model, starts by defining the refractive error as the difference between the axial power (or dioptric distance) and the whole eye power, which can be expanded by filling in the formulas for each power. The resulting equation can be solved for either the refractive error, axial length, corneal power, lens power or the distance between the cornea and the lens as a function of the other four parameters. The second approach uses vergence calculations to provide alternative expressions, assuming that the refractive error is located at the corneal plane. Both models are explored for a biometric range typically found in adult human eyes. Results: The Gaussian and vergence models each instantly balance the input data into a working eye model over the human physiological range and far beyond as demonstrated in various examples. The equations of the Gaussian model are more complicated, while the vergence model experiences more singularities, albeit in trivial or highly unlikely parameter combinations. Conclusions: The proposed equations form a flexible and robust platform to create eye models from clinical data. Possible applications lie in creating animal eye models or providing a generic reference for real biometric data and the relationships between the ocular dimensions. [ABSTRACT FROM AUTHOR]

Background: During the subjective measurement of astigmatic refractive error, the recommended targets for the Jackson Cross Cylinder (JCC) test are interchanged often depending on availability, convenience, and preference of clinicians. However, reliability of the JCC test becomes uncertain. Methods: A cross-sectional, quantitative research design was used to compare measurements of cylinder power and axis with the JCC test but with three different targets (a cluster of random dots, the letter O, and the letter H). Randomisation of order of targets was applied to prevent biases. Data was captured using SPSS (version 27) and analysed using dependent-samples Wilcoxon signed-rank tests and Bland-Altman plots at a 95% confidence level. Results: A total of 61 left eyes of 72 subjects, with cylinders of at least -0.50 D after subjective refraction, were analysed. The study found no statistically or clinically significant difference in the subjective measurement of cylindrical power and axis with the JCC test irrespective of the target used. Random dots and the letter H were the most and the least preferred targets, respectively. Conclusion: The clinical implication of this study is that random dots, circular letters, and non-circular letters can be used interchangeably to measure the cylinder power and axis of mild astigmatism. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the effect of individualized ocular refraction customized (IORC) spectacle lenses with different actual amounts of peripheral myopic defocus (MD) on myopia control over 1 year. These lenses compensate for the original peripheral refraction via the free‐form surface on the back of the lens. Methods: This 1‐year, double‐masked randomised clinical trial included 184 myopic schoolchildren aged 8–12 years. Participants were randomised to receive IORC lenses with high (IORC‐H group, +4.50 D), medium (IORC‐M group, +3.50 D) or low (IORC‐L group, +2.50 D) MD or single‐vision (SV) lenses. The spherical equivalent refractive error (SER) and axial length (AL) were measured at baseline and 6‐monthly intervals. Results: After 1 year, the mean (SD) changes in SER were −0.18 (0.37), −0.36 (0.37), −0.52 (0.39) and −0.60 (0.42) D for the IORC‐H, IORC‐M, IORC‐L and SV groups, respectively. Compared with the SV group, the effects of slowing myopia progression were 70%, 40% and 13% for the IORC‐H (difference of 0.47 D, p < 0.001), IORC‐M (difference of 0.32 D, p = 0.001) and IORC‐L (difference of 0.15 D, p > 0.05) groups, respectively. The mean (SD) changes in AL were 0.12 (0.16), 0.23 (0.17), 0.29 (0.17) and 0.36 (0.17) mm for the IORC‐H, IORC‐M, IORC‐L and SV groups, respectively. The axial elongation was 67%, 36% and 19% lower in the IORC‐H (difference of 0.25 mm, p < 0.001), IORC‐M (difference of 0.15 mm, p < 0.001) and IORC‐L (difference of 0.10 mm, p = 0.04) groups, respectively, compared with the SV group. The IORC‐H group exhibited significantly less axial elongation than the IORC‐M and IORC‐L groups (p = 0.01 and p < 0.001, respectively). Conclusion: Compared with the IORC‐M and IORC‐L lenses, the IORC‐H lens was found to have superior efficacy in inhibiting myopic progression and slowing eye growth in schoolchildren, with better myopia control efficacy in younger children. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the difference between cycloplegic and noncycloplegic refraction and evaluate the pseudomyopia prevalence in Chinese preschool children during the outbreak of COVID-19. Methods: A cross-sectional study was conducted in the Tongzhou District of Beijing, China. Refractive error was measured under both noncycloplegic and cycloplegic conditions with autorefraction. The difference between noncycloplegic and cycloplegic spherical equivalent refraction (SER) and pseudomyopia prevalence were analyzed. Pseudomyopia was defined as SER ≤-0.50D in precycloplegic assessments and >-0.50D in post-cycloplegic assessments. Results: Out of the 1487 participants who were enrolled in the study, 1471 individuals (98.92%) between the ages of 3–6 years completed all required procedures. A statistically significant difference in refraction was observed between noncycloplegic and cycloplegic measurements, the median of difference in spherical equivalent refraction (SER) of 0.88D (dioptre)(0.50,1.38). There was a high intraclass correlation (ICC) between these two methods for cylinders (ICC = 0.864; 95% CI, 0.850–0.877). The median DSE for myopia, emmetropia and hyperopia were 0.25D (0.00, 0.38),0.25D (0.06, 0.50) and 1.00D (0.62, 1.38), an hypermetropes showed considerably greater differences than myopes and emmetropes (Kruskal-Wallis test, H = 231.023, P = 0.000). Additionally, girls displayed a greater DSE than boys. Furthermore, when comparing against-the-rule (ATR) and oblique astigmatism, it was found that with-the-rule (WTR) astigmatism had the largest DSE. The study found varying prevalence rates of myopia, emmetropia, and hyperopia with and without cycloplegia, which were 1.90% vs. 10.06%, 11.49% vs. 50.31%, and 86.61% vs. 39.63%, respectively. Additionally, the overall prevalence of pseudomyopia was determined to be 8.29%. Participants with pseudomyopia had a significantly higher mean difference in SER (DSE) compared to non-pseudomyopic participants. Conclusions: Cycloplegic refraction is more sensitive than a noncycloplegic one for measuring refractive error in preschool children. Pseudomyopia is prevalent in preschool children during the COVID-19 outbreak period. Our study indicates the possibility that cycloplegic refraction should be performed in preschool children routinely. [ABSTRACT FROM AUTHOR]

Introduction. Peripheral retinal refraction plays a crucial role in myopia, but the specific mechanism is not clear. We refined the retinal partitions to explore the characteristics of peripheral retinal refraction and its role in emmetropic, low, and moderate myopic children aged 6 to 12 years. Methods. A total of 814 subjects (814 eyes) were enrolled in the study. The participants were divided into three groups according to the central spherical equivalent refraction (SER), which were emmetropia group (E), low myopia group (LM) and moderate myopia group (MM). Multispectral refractive topography (MRT) was used to measure the retinal absolute and relative refractive difference value (RDV) in different regions. The range was divided into superior, inferior, temporal, and nasal RDV (SRDV, IRDV, TRDV, and NRDV) on the basis of several concentric circles extending outward from the macular fovea (RDV15, RDV30, RDV45, RDV30–15, RDV45–30, and RDV‐45). Kruskal–Wallis test was used to analyze the differences of peripheral refraction for all the regions among the three groups. Spearman rank correlation was performed to explore correlations between SER and RDV, axial length (AL) and RDV. Results. The absolute value of RDV decreased with increasing degree of myopia in all regions (P < 0.01). Subjects with different refractive degrees had different relative value of RDV. In nasal position within 45° and temporal position within 30°, the peripheral retina exhibited significantly different relative hyperopic refractive status among Group E, Group LM, and Group MM (P < 0.05). SER was negatively correlated with NRDV within 30° (especially in the range of NRDV30–15) (r = −0.141, P < 0.01), positively correlated with TRDV within 15° (r = 0.080, P = 0.023), and not significantly correlated with SRDV and IRDV when the retina was divided into four parts. AL was positively correlated with NRDV within 30° (especially in the range of NRDV30–15) (r = 0.109, P = 0.002), negatively correlated with TRDV within 15° (r = −0.095, P = 0.007). Conclusions. The peripheral defocus has significant implications for the genesis of myopia. The peripheral defocus of the horizontal direction, especially within the range of NRDV30, has greater effect on the development of myopia in children. Higher NRDV30 is associated with lower SER and longer AL. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the accuracy of a new intraocular lens power calculation formula using segmental refractive index-based axial length (AL). Setting: Chukyo Eye Clinic, Nagoya, Japan. Design: Retrospective observational study. Methods: This study included patients undergoing preoperative examination for cataract surgery with the new Barrett True AL (BTAL) and Emmetropia Verifying Optical (EVO) formulas using segmental refractive index, and conventional Barrett Universal II (BU II) formula using equivalent refractive index. The predicted refractive error of each formula was compared with the postoperative subjective spherical equivalent. Results: The mean prediction error (MPE) in the short AL group (=22 mm; 44 eyes) was 0.32 ± 0.40 diopter (D) for BU II, 0.22 ± 0.37 D for BTAL, and 0.10 ± 0.37 D for EVO (P < .0001). MPE in the long AL group (=26mm; 92 eyes) was 0.01 ± 0.32 D for BU II, 0.04 ± 0.32 D for BTAL, and 0.09 ± 0.32D for EVO(P < .0001). In patients with an AL = 28 mm, BU II showed a myopic trend in 57.1% of cases, while BTAL and EVO showed a hyperopic trend in 71.4%. The MPE for patients with an AL = 28 mm was -0.16 ± 0.34 D for BU II, 0.18 ± 0.33 D for BTAL, and 0.16 ± 0.32 D for EVO (P < .0001). Conclusions: The new EVO and BTAL formulas showed higher accuracy than BU II in short eyes, whereas there was no difference in long eyes. [ABSTRACT FROM AUTHOR]

(1) Background: This study compares the effective lens position (ELP) and intraocular lens power (IOLP) derived from SRK/T, Hoffer Q, Holladay I, and Haigis formulas with the actual lens position (ALP) and the implanted IOLP after cataract surgery. Additionally, it aims to optimize ALP using a ray-tracing-based simulated optical model to achieve emmetropia. (2) Methods: A retrospective observational study was conducted on 43 eyes implanted with the same monofocal intraocular lens (IOL). Preoperative and postoperative biometric data were collected using the Lenstar LS900. Postoperative measurements included ALP, subjective refraction, and refraction error (RE). Optical simulations (OSLO EDU 6.6.0) were utilized to optimize ALP for emmetropia (ALPIDEAL). (3) Results: Paired t-test results between REOSLO-REOBJ (p-value = 0.660) and REOSLO-RESUB (p-value = 0.789) indicated no significant statistical differences. However, statistically significant differences were found between ALP and ALPIDEAL (p < 0.05), with a difference of −0.04 ± 0.45 mm [ranging from −1.00 to 1.20 mm]. A significant correlation was observed between ΔALP (ΔALP = ALP − ALPIDEAL) and RESUBJ. (4) Conclusions: This customized ray-tracing eye model effectively achieves refractive outcomes similar to those obtained both subjectively and objectively post-surgery. Additionally, it has enabled optical simulations to optimize the IOL position and achieve emmetropia. [ABSTRACT FROM AUTHOR]

Purpose: To present a paraxial method to estimate the influence of variations in ocular biometry on changes in refractive error (S) at a population level and apply this method to literature data. Methods: Error propagation was applied to two methods of eye modelling, referred to as the simple method and the matrix method. The simple method defines S as the difference between the axial power and the whole‐eye power, while the matrix method uses more accurate ray transfer matrices. These methods were applied to literature data, containing the mean ocular biometry data from the SyntEyes model, as well as populations of premature infants with or without retinopathy, full‐term infants, school children and healthy and diabetic adults. Results: Applying these equations to 1000 SyntEyes showed that changes in axial length provided the most important contribution to the variations in refractive error (57%–64%), followed by lens power/gradient index power (16%–31%) and the anterior corneal radius of curvature (10%–13%). All other components of the eye contributed <4%. For young children, the largest contributions were made by variations in axial length, lens and corneal power for the simple method (67%, 23% and 8%, respectively) and by variations in axial length, gradient lens power and anterior corneal curvature for the matrix method (55%, 21% and 14%, respectively). During myopisation, the influence of variations in axial length increased from 54.5% to 73.4%, while changes in corneal power decreased from 9.82% to 6.32%. Similarly, for the other data sets, the largest contribution was related to axial length. Conclusions: This analysis confirms that the changes in ocular refraction were mostly associated with variations in axial length, lens and corneal power. The relative contributions of the latter two varied, depending on the particular population. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to suggest a new method to calculate the intraocular lens (IOL) power in paediatric cataracts targeting emmetropia at the age of 15 years. Methods: Data of children younger than 15 years who underwent cataract surgery with IOL implantation between 2005 and 2020 in the ophthalmological department of Marseille (South of France) was collected retrospectively. A logarithmic regression model was used to predict the axial length growth of the included eyes between implantation and 15 years. The predicted myopic shift served as target refraction to calculate a theoretical IOL power aiming for emmetropia at 15 years. Refractive error with the theoretical lens power was estimated as the spherical equivalent at the last follow‐up minus the difference of target refractions between the implanted IOL and the theoretical one. Refractive errors using Dahan, Enyedi and Trivedi guidelines were also estimated and compared to the logarithmic model. Results: Thirty‐five eyes of 26 children were analysed. At the last follow‐up, the median age of children was 10 years old and the median spherical equivalent was −1.88 dioptres (D) (IQR −3.81, −0.75). The estimated median refractive errors were 0.18 D (IQR −1.11, 1.42) with the logarithmic formula, −1.47 D (IQR −3.84, −0.65) with Dahan formula, −0.63 D (IQR −2.15, 0.32) with Enyedi formula and 0.38 D (IQR −1.58, 1.07) with Trivedi formula. Conclusion: The estimated refractive error with the new logarithmic formula is the closest to emmetropia at the last follow‐up. [ABSTRACT FROM AUTHOR]

Purpose. To compare the refractive errors measured by the Spot photoscreener (with or without cycloplegia) to cycloplegic retinoscopy in 6- to 10-week-old infants. Materials and Methods. 101 right eyes from 101 healthy infants aged 6 to 10 weeks were recruited for this cross-sectional observational study. Refractive errors were measured using Spot photoscreener before and after cycloplegia, as well as cycloplegic retinoscopy. Comparisons between the refractive measurements were performed using one-way ANOVA with the post hoc Tukey HSD test or Kruskal–Wallis test with the Steel–Dwass test according to the data normality. Pearson's correlation test and 95% confidence intervals were calculated. The agreement was evaluated using a Bland–Altman plot with 95% limits of agreement of the differences. Results. Spot photoscreener was found to underestimate the spherical equivalent by 2.33 Diopters (D) in these infants. Following the induction of cycloplegia, the spherical equivalent measured by Spot photoscreener was in excellent agreement with cycloplegic retinoscopy with the mean difference of 0.01 D. Spot photoscreener overestimated cylindrical parameter by 0.2 D with poor agreement with cycloplegic retinoscopy no matter whether cycloplegia was induced. It had good agreement with cycloplegic retinoscopy in the J 0 vector than the J 45 vector measurement. Conclusions. With the induction of cycloplegia, Spot photoscreener can accurately evaluate spherical equivalent in hyperopic infants with mild-to-moderate astigmatism. While it may provide valuable measurements of astigmatism, discrepancies in cylinder and axis should be taken into account. [ABSTRACT FROM AUTHOR]

Purpose: To understand the ocular biometric parameters characteristics and refractive errors in 3-to 6-year-old preschool children in Chengdu, China, and to investigate the prevalence of refractive errors. Method: A school-based cross-sectional study was conducted in Chengdu from 2020 to2022 with a total of 666 kindergartens. All children were measured by non-cycloplegic autorefraction and uncorrected visual acuity (UCVA) and ocular biometric parameters. Finally, univariate linear regression models were used to analyze the relationship between ocular biometric parameters and refraction. Results: A total of 108,578 preschool children aged 3–6 underwent examinations, revealing a myopia prevalence of 6.1%. The mean axial length (AL), keratometry (K), corneal radius (CR), axial length/corneal radius (AL/CR) Ratio, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and vitreous chamber depth (VCD) were 22.35 ± 0.69 mm, 43.35 ± 1.58 D, 7.80 ± 0.28 mm, 2.87 ± 0.08, 533.31 ± 32.51 μm, 2.70 ± 0.28 mm, 3.91 ± 0.27 mm, and 15.20 ± 0.68 mm, respectively. With increasing age, AL, CR, AL/CR ratio, CCT, ACD, LT, and VCD also increased. Regardless of age, males consistently exhibited longer AL, flatter corneal curvature, shallower ACD, thicker CCT, thinner LT, and longer VCD compared to females. AL, K, CR, LT, and VCD all showed significant linear relationships with SE (all P < 0.001) in univariate linear regression analysis after adjusting for gender and age. Conclusion: The prevalence of myopia among preschool children aged 3–6 in Chengdu is relatively low. Ocular biometric parameters affecting refractive errors include AL, K, CR, LT, and VCD. The preschool period serves as a critical phase for myopia prevention and control. [ABSTRACT FROM AUTHOR]

Objective was to compare the accuracy of three formulas (IA; Sanders, Retzlaff, and Kraff/Theoretical (SRK/T); and Barrett Universal II (BUII)), in achieving emmetropia in eyes implanted with TFNT lenses (Alcon). Patients and Methods: A total of 145 eyes of 145 patients were included in the evaluation. Preoperative data were obtained from IOLMaster 700, while intraoperative data were collected from ORA SYSTEMTM. Visual acuity ≥ 0.8 at the 3-month post-surgery mark was confirmed. We assessed refractive prediction error (RPE), which is the difference between predicted refraction (PR) and postoperative subjective refraction. This evaluation aimed to identify the optimal IOL power with the implemented algorithm. Results: Among the 145 eyes evaluated, 55.9%, 78.7%, and 97.2% achieved postoperative subjective refraction within ± 0.13 Diopters (D), ± 0.25 D, and ± 0.50 D, respectively. The percentages of eyes within ± 0.25 D of PR varied by formula type, with values of 57%, 57%, and 54% for IA, BUII, and SRK/T, respectively. For eyes with short to medium axial length (AL< 26.00 mm), the percentages within ± 0.25 D of RPE were 52%, 58%, and 58% for IA, SRK/T, and BUII, respectively. In contrast, for eyes with long axial length (≥ 26.00 mm) the percentages were 68%, 52%, and 45% for IA, BUII, and SRK/T, respectively. Conclusion: The proposed majority decision algorithm incorporating IA and two IOL frequency formulas was effective in reducing postoperative refractive error. IA was particularly beneficial for eyes with long axial length. These findings suggest the algorithm has potential to optimize IOL power selection to improve quality of life of patients and clinical practice outcomes. [ABSTRACT FROM AUTHOR]

Background: This study aimed to compare the results of the Chronos binocular/monocular refraction system, that measures objective and subjective ocular refraction in one unit, to objective findings obtained from a conventional autorefractometer and a conventional subjective ocular refraction using a trial-frame in real space. Methods: Twenty-eight healthy volunteers (21.2 ± 1.5 years old) were included in this study. Objective ocular refraction was measured using two tests: the Chronos binocular/monocular refraction system under binocular conditions and a conventional autorefractometer under monocular conditions. Subjective ocular refraction was measured using three tests: Chronos binocular/monocular refraction system under binocular, monocular conditions, and trial-frame in the real space under monocular conditions. The measurement distance was set to 5.0 m for each test. All ocular refractions were converted into spherical equivalents (SEs). Results: The objective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (− 4.08 ± 2.76 D) than with the conventional autorefractometer under monocular condition (− 3.85 ± 2.66 D) (P = 0.002). Although, the subjective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (− 3.55 ± 2.67 D) than with the trial-frame in the real space under monocular condition (− 3.33 ± 2.75 D) (P = 0.002), Chronos binocular/monocular refraction system under monocular condition (− 3.17 ± 2.57 D) was not significantly different from that in trial-frame in real space under monocular condition (P = 0.33). Conclusion: These findings suggest that the Chronos binocular/monocular refraction system, which can complete both objective and subjective ocular refraction tests in a single unit, is suitable for screening ocular refraction, although it produces slightly more myopic results. Furthermore, subjective ocular refraction testing accuracy in Chronos binocular/monocular refraction system can be equivalent to trial-frame in real-space testing by switching from binocular to monocular condition. [ABSTRACT FROM AUTHOR]

Background: Determination of the number of pupils at risk of developing pre-myopia and selected ophthalmic parameters in a group of 1155 children aged 8. Material: Ophthalmic examinations were performed in Polish 8-year-old, /1518 individuals/; 1155 of whom presented complete data for analysis. There was a total of 554 (47.9%) girls and 602 (52.1%) boys. Examination of the anterior and posterior segment of the eye, evaluation of accommodation, convergence, heterophoria, alignment of the eyeball, muscular balance with ocular mobility in 9 directions of gaze, and spatial vision were tested. Refraction was obtained under cycloplegia. Refractions (spherical equivalent, SE). were categorized as pre-myopia (−0.50 D–+0.75 D), myopia (≤−0.5 D), emmetropia (>−0.5 D to ≤+0.5 D), mildly hyperopia (>+0.5 D to ≤+2.0 D) and hyperopia (>+2.0 D). Data analysis was performed using Statistica 13.5 software: chi-squared, Pearson's, t-Student, and U Mann–Whitney tests. p-values of <0.05 were considered statistically significant. Results: Pre-myopia was diagnosed in as many as 704 subjects (60.9%) with a similar frequency among both girls—328 (46.6%)—and boys with 376 (53.4%). Conclusions: Current data indicates that the growing group of myopic individuals in many industrialized countries is the sixth most common cause of blindness. Further research is crucial to understand the factors underlying accommodative and binocular mechanisms for myopia development and progression and to make recommendations for targeted interventions to slow the progression of myopia in a group of early school children. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of nine conventional and newer-generation formulae in calculating intraocular lens power in eyes with axial myopia. Setting: Tertiary eye care center, Bengaluru, India. Design: Retrospective cross-sectional, comparative study conducted in India. Methods: Patients undergoing uneventful phacoemulsification in eyes with axial length >26 mm were included. Preoperative biometry was done using Lenstar LS 900 (Haag-Streit AG, Switzerland). Single eye of patients undergoing bilateral implantation was randomly selected. Optimized lens constants were used to calculate the predicted postoperative refraction of each formula, which was then compared with the actual refractive outcomes to give the prediction errors, following which subgroup analysis was performed. The Kane formula, Barrett universal II, Emmetropia Verifying Optical (EVO) 2.0, Hill Radial Basis Function (Hill RBF) 3.0, Olsen formula, along with Wang Koch-adjusted four formulae, that is, Sanders Retzlaff Kraff/Theoretical (SRK/T), Holladay 1, Haigis, and Hoffer Q formula, were compared for intraocular lens power calculations. Results: One hundred and sixty-five eyes that fulfilled all the inclusion criteria were studied. Hill RBF 3.0 had the lowest mean and median absolute prediction errors (0.355 and 0.275, respectively) compared to all formulas. In subgroup analysis (26-28, >28-30, and >30 mm), significant difference was seen only in extremely long eyes (>30 mm). The Hill RBF 3.0 formula generated the maximum percentage of eyes with refractive errors within ±0.25, ±0.5, ±0.75, and ±1 D (46%, 76.2%, 89.9%, and 95.8%, respectively). Conclusion: This is the first study evaluating all the formulas exclusively in the myopic eyes. Hill RBF 3 was found to be superior in accuracy to all other formulas. [ABSTRACT FROM AUTHOR]

Objectives: Determining the accuracy of cycloplegic refractive error measurements made with the Spot Vision Screener (SVS, Welch Allyn Inc, Skaneateles Falls, NY, USA) is important for refractive assessment of uncooperative patients during optometric examinations. This study compared cycloplegic refractive errors measured by SVS and tabletop autorefractometer to cycloplegic retinoscopy in children. Materials and Methods: Eighty-eight eyes of 44 subjects were examined in the study. Refractive error measurements were obtained under cycloplegia using retinoscopy, SVS, and Nidek ARK-530 tabletop autorefractometer (ARK-530, Nidek, Japan). Spherical and cylindrical values, spherical equivalents (SE), and Jackson cross-cylinder values at axes of 0° (J0) and 45° (J45) were recorded. Correlations between methods were analyzed using intraclass correlation coefficient (ICC) and Bland-Altman analysis. Results: The mean age was 7 years (range: 6 months-17 years). Sixteen (36%) of the subjects were female and 28 (64%) were male. For SE there was excellent agreement between retinoscopy and SVS (ICC: 0.924) and between retinoscopy and tabletop autorefractometer (ICC: 0.995). While there was a moderate correlation between retinoscopy and SVS for cylindrical values (ICC: 0.686), excellent correlation was detected between retinoscopy and autorefractometer (ICC: 0.966). J0 and J45 cross- cylinder power values were not correlated between retinoscopy and SVS (ICC: 0.472) or retinoscopy and tabletop autorefractometer (ICC: 0.442). Retinoscopy was correlated with both SVS and tabletop autorefractometer for all parameters within ±1.96 standard deviations in Bland-Altman analysis. Conclusion: Cycloplegic retinoscopy is the gold standard for refractive error measurement in the pediatric population. However, it requires time and experienced professionals. This study revealed moderate to good agreement between SVS and retinoscopy, with better agreement in spherical errors than cylindrical errors. Although the SVS is intended for screening programs, it may also be useful in the pediatric eye office to estimate spherical refractive error in uncooperative patients. [ABSTRACT FROM AUTHOR]

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Purpose: To report the refractive outcomes of long (≥25.00 mm) and short (≤22.00 mm) axial length (AL) eyes undergoing immediately sequential bilateral cataract surgery (ISBCS). Methods: In this retrospective cohort study, patients who underwent ISBCS were identified and eyes of patients with bilateral long and short ALs were included. Pre- and postoperative biometry, autorefraction, and ocular comorbidities or complications were recorded. The primary outcome was the mean refractive prediction error. Results: Thirty-seven patients (74 eyes) with long ALs and 18 patients (36 eyes) with short ALs were included. The means ± standard deviations of the ALs were 26.40 ± 1.38 mm and 21.44 ± 0.46 mm in the long and short AL groups, respectively. In long AL eyes, the mean absolute error from the biometry-predicted refraction was − 0.16 ± 0.46 D, corresponding to 74% of eyes achieving a refraction within ±0.50 D of the predicted value. In short AL eyes, the mean absolute error was − 0.63 ± 0.73 D, corresponding to 44% of eyes achieving a refraction within ±0.50 D of the predicted value. Eight (44.4%) patients with short AL eyes had a myopic deviation greater than ±0.50 D from the predicted result in both eyes. Conclusions: Compared to patients with long AL eyes, ISBCS in patients with short ALs had a wider variance in refractive outcome and a lower rate of achieving a postoperative refraction within ±0.50 D of the predicted target. [ABSTRACT FROM AUTHOR]

To investigate the association between the peripheral refractive errors of the fundus in different regions and moderate and high myopia. Methods: In this case-control study, 320 children and adolescents aged 6 to 18 years were recruited. Peripheral refractive errors were measured using multispectral retinal refractive topography (MRT). Spherical equivalent (SE) and cylinder errors were classified into low, moderate, and high categories based on the magnitude range. Logistic regression was performed to test the factors associated with myopia. Results: There were 152 participants with low myopia and 168 participants with moderate and high myopia included in the current study. Participants with moderate and high myopia were most likely to be older, with larger axial length (AL), lower SE, less time to watch electronic devices on the weekend, a higher difference between central refractive error and paracentral refractive error from the superior side of the retina (RDV-S), but a smaller difference between the central refractive error and paracentral refractive error from the inferior side of the retina (RDV-I) than those with low myopia (all P < 0.05). After logistic analysis, female sex (odds ratio [OR] = 4.14; 95% confidence interval [CI] = 2.16– 7.97, P < 0.001), AL (OR = 6.88, 95% CI = 4.33– 10.93, P < 0.001), and RDV-I (OR = 0.52, 95% CI = 0.32– 0.86, P = 0.010) were independent factors for moderate and high myopia. Conclusion: Our study demonstrated that the retina peripheral refraction of the eyes (RDV-I) was associated with moderate and high myopia, and RDV-S was only associated with high myopia. [ABSTRACT FROM AUTHOR]

Background: To compare the accuracy of nine intraocular lens (IOL) power calculation formulas, including three traditional formulas (SRK/T, Haigis, and Hoffer Q) and six new-generation formulas (Barrett Universal II [BUII], Hill-Radial Basis Function [RBF] 3.0, Kane, Emmetropia verifying optical [EVO], Ladas Super, and Pearl-DGS) in patients who underwent cataract surgery after acute primary angle closure (APAC). Methods: In this retrospective cross-sectional study, 44 eyes of 44 patients (APAC) and 60 eyes of 60 patients (control) were included. We compared the mean absolute error, median absolute error (MedAE), and prediction error after surgery. Subgroup analyses were performed on whether axial length (AL) or preoperative laser peripheral iridotomy affected the postoperative refractive outcomes. Results: In the APAC group, all formulas showed higher MedAE and more myopic shift than the control group (all P < 0.05). In APAC eyes with AL ≥ 22 mm, there were no differences in MedAEs according to the IOL formulas; however, in APAC eyes with AL < 22 mm, Haigis (0.49 D) showed lower MedAE than SRK/T (0.82 D) (P = 0.036) and Hill-RBF 3.0 (0.54 D) showed lower MedAE than SRK/T (0.82 D), Hoffer Q (0.75 D) or Kane (0.83 D) (P = 0.045, 0.036 and 0.027, respectively). Pearl-DGS (0.63 D) showed lower MedAE than Hoffer Q (0.75 D) and Kane (0.83 D) (P = 0.045 and 0.036, respectively). Haigis and Hill-RBF 3.0 showed the highest percentage (46.7%) of eyes with PE within ± 0.5 D in APAC eyes with AL < 22 mm. Iridectomized eyes did not show superior precision than the non-iridotomized eyes in the APAC group. Conclusions: Refractive errors in the APAC group were more myopic than those in the control group. Haigis and Hill-RBF 3.0 showed high precision in the eyes with AL < 22 mm in the APAC group. [ABSTRACT FROM AUTHOR]

This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near tasks. The sustained accommodative and vergence characteristics of participants without refractive correction (n = 92, aged 5–10 years) with and without hyperopia (defined as cycloplegic retinoscopy ≥ + 1.00D and less than + 5.00D) were measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular measures of accommodation and eye position were recorded while participants engaged in 2 tasks at 25 cm for 15 min each: (1) reading small print on an Amazon Kindle and (2) watching an animated movie on liquid crystal display screen. Comprehensive visual assessment, including measurement of presenting visual acuity, amplitude of accommodation, and stereoacuity was conducted. The magnitude of accommodative and vergence responses was not related to refractive error (P > 0.05). However, there were inter-task differences in the accuracy and stability of the accommodative responses across refractive groups (P < 0.05). The relationship between accommodation and vergence was not significant in both tasks (P > 0.05). However, increased accommodative and vergence instabilities were associated with total accommodative response (P < 0.05). Despite having greater accommodative demand, uncorrected hyperopes accommodate comparably to emmetropic controls. However, uncorrected hyperopes have increased instabilities in their accommodative and vergence responses, which may adversely impact their visual experience. [ABSTRACT FROM AUTHOR]

High-contrast visual acuity is disproportionately poor in patients with accommodative spasm subtype of near reflex (SNR-A), relative to uncorrected refractive errors of equivalent magnitude. This exaggerated loss of performance in SNR-A may be explained by the combination of pseudomyopia and its fluctuations, vis-à-vis, each factor considered separately. To determine how combinations of pseudomyopic refraction and its temporal variations in SNR-A impact high-contrast visual acuity by inducing these patterns in healthy cyclopleged adults, relative to their baseline acuity. Refractive profiles of 15 patients with SNR-A were obtained from a previous study, averaged, and induced before the right eye of 14 cyclopleged adults (mean ±1 SD age: 22.7 ± 2.6 yrs) by feeding the profile into a coaxially placed, motorised, Badal optometer. LogMAR acuity was measured using the method of constant stimuli: (1) before cycloplegia, (2) after cycloplegia and post-cycloplegia with (3) combination of pseudomyopia and its temporal fluctuations, (4) only pseudomyopia, (5) only temporal fluctuations in refraction about emmetropia, (6) condition 5 with double the amplitude of induced fluctuations and (7) condition 5 with half the amplitude of induced fluctuations. The induced refractive fluctuations ranged from −0.80 to −1.75D, around a mean pseudomyopia of −1.20D. Visual acuity deterioration was maximum for the combination of pseudomyopia and temporal fluctuations condition (0.51 ± 0.07logMAR), followed by only pseudomyopia (0.27 ± 0.05logMAR) and only refractive fluctuations conditions (0.17 ± 0.04logMAR), all relative to baseline post-cycloplegia (0.13 ± 0.04logMAR) (p < 0.001). Visual acuity loss increased with doubling of refractive fluctuations (0.20 ± 0.04logMAR), relative to native fluctuations or halving the amplitude (0.15 ± 0.03logMAR) (p < 0.01). Task precision, as adjudged from the slope of psychometric function, followed a similar pattern of loss as visual acuity. Combination of induced pseudomyopia and temporal fluctuations in refraction produces an additive loss of visual acuity and task precision, relative to baseline and each factor considered separately. [ABSTRACT FROM AUTHOR]

Purpose: Bright light conditions are supposed to curb eye growth in animals with experimental myopia. Here we investigated the effects of temporal bright light at very low frequencies exposures on lens-induced myopia (LIM) progression. Methods: Myopia was induced by application of -6.00 D lenses over the right eye of guinea pigs. They were randomly divided into four groups based on exposure to different lighting conditions: constant low illumination (CLI; 300 lux), constant high illumination (CHI; 8,000 lux), very low frequency light (vLFL; 300/8,000 lux, 10 min/c), and low frequency light (LFL; 300/8,000 lux, 20 s/c). Refraction and ocular dimensions were measured per week. Changes in ocular dimensions and refractions were analyzed by paired t-tests, and differences among the groups were analyzed by one-way ANOVA. Results: Significant myopic shifts in refractive error were induced in lens-treated eyes compared with contralateral eyes in all groups after 3 weeks (all P < 0.05). Both CHI and LFL conditions exhibited a significantly less refractive shift of LIM eyes than CLI and vLFL conditions (P < 0.05). However, only LFL conditions showed significantly less overall myopic shift and axial elongation than CLI and vLFL conditions (both P < 0.05). The decrease in refractive error of both eyes correlated significantly with axial elongation in all groups (P < 0.001), except contralateral eyes in the CHI group (P = 0.231). LFL condition significantly slacked lens thickening in the contralateral eyes. Conclusions: Temporal bright light at low temporal frequency (0.05 Hz) appears to effectively inhibit LIM progression. Further research is needed to determine the safety and the potential mechanism of temporal bright light in myopic progression. [ABSTRACT FROM AUTHOR]

To assess the agreement between the Eye Refract, an instrument to perform subjective automated refraction, and the traditional subjective refraction, as the gold standard, in young hyperopes under noncycloplegic and cycloplegic conditions. A cross-section and randomized study was carried out, involving 42 participants (18.2 ± 7.7 years, range 6 to 31 years). Only one eye was chosen for the analysis, randomly. An optometrist conducted the refraction with the Eye Refract, while another different optometrist conducted the traditional subjective refraction. Spherical equivalent (M), cylindrical components (J0 and J45), and corrected distance visual acuity (CDVA) were compared between both refraction methods under noncycloplegic and cycloplegic conditions. A Bland-Altman analysis was performed to assess the agreement (accuracy and precision) between both refraction methods. Without cycloplegia, the Eye Refract showed significantly lower values of hyperopia than the traditional subjective refraction (p < 0.009), the mean difference (accuracy) and its 95% limits of agreement (precision) being -0.31 (+0.85, -1.47) D. Conversely, there were no statistical differences between both refraction methods under cycloplegic conditions (p ≥ 0.05). Regarding J0 and J45, both refraction methods manifested no significant differences between them under noncycloplegic and cycloplegic conditions (p ≥ 0.05). Finally, the Eye Refract significantly improved CDVA (0.04 ± 0.01 logMAR) compared with the traditional subjective refraction without cycloplegia (p = 0.01). The Eye Refract is presented as a useful instrument to determine the refractive error in young hyperopes, the use of cycloplegia being necessary to obtain accurate and precise spherical refraction. [ABSTRACT FROM AUTHOR]

Purpose: To assess the accuracy of five new-generation intraocular lens (IOL) power formulas: Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) Formula, Hill-Radial Basis Function (Hill-RBF), Kane Formula, and Ladas Super Formula (LSF).Patients and Methods: This is a retrospective single-surgeon study from a refractive clinic and clinical research center in Draper, UT, USA. The primary outcome measures were mean absolute error (MAE) and median absolute error (MedAE). Secondary outcome measures were the standard deviation (SD) of each formula's refractive prediction errors (RPE) and the percentage of eyes within ± 0.50D. Refractive predictions were compared to the postoperative spherical equivalent to determine the RPE for each formula. RPEs were optimized, and MAE, MedAE, SD of the AME, and percent of eyes achieving RPEs within the specified ranges of ± 0.125 D, ± 0.25 D, ± 0.50 D, ± 0.75 D, ± 1.0 D were calculated. Subgroup analysis between different axial lengths was attempted but yielded insufficient statistical power to draw meaningful conclusions.Results: A total of 103 eyes of 103 patients were included in our study after applying inclusion and exclusion criteria to 606 eyes from 2019 to 2021. Formulas ranked in ascending order by MAE were Kane, EVO, BUII, Hill-RBF, and LSF. The ascending rankings of MedAE were Kane, BUII, Hill-RBF, EVO, Ladas. Kane had a significantly lower MAE than Hill-RBF (p< 0.001). EVO had the lowest SD of AMEs and the highest percentage of eyes within ± 0.50 D. According to heteroscedastic testing, EVO also had a statistically significant lower SD than Hill-RBF.Conclusion: Kane was the most accurate formula in terms of MAE and MedAE. EVO and BUII achieved marginally higher MAEs than Kane, suggesting these three formulas are comparable in performance. With the exception EVO and Hill-RBF, the heteroscedastic test yielded no significant differences in SD between the formulas. Although there were multiple statistically significant differences between the formulas in terms of MAE, MedAE, and SD, these differences may not be appreciable clinically. Lastly, there were no statistically significant differences in the percent of eyes with RPEs within ± 0.50 D, suggesting similar clinical performance between formulas. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the normal refractive state in horses in NCSU and ECMR and determine the prevalence of naturally occurring refractive errors and their association with breed, age, coat color, iris color, sex, and geographic location. Methods: Horses from NCSU (January 2009–November 2012) and ECMR (January 2013–September 2016) underwent ophthalmic examination and streak retinoscopy. Location, color, breed, sex, and iris color were recorded. Gross and net refractive values for each meridian (horizontal and vertical), spherical refraction, astigmatism for both eyes, and anisometry were recorded, and statistical analyses were performed. Results: There is excellent agreement in refraction between the eyes of the same horse (ICC = 0.89). The median net horizontal (H), vertical (V), and spherical refraction for the total population (n = 690) were H: +0.25 D (min. −6.50 D, max. +2.34 D), V: +0.25 D (min. −7.13 D, max. +2.75D), and spherical: +0.25 D (min. −6.82 D, max. +2.17 D), all with interquartile ranges of −0.25 to 0.25 D. Emmetropia (>−0.50 D and <+0.50 D; >−0.75 D and <+0.75 D) was present in 769/1380 eyes (55.7%) and 926/1380 eyes (67.1%), respectively. Anisometropia was present in 86/690 horses (12.5%). Sex, iris color, and location were significantly associated with refraction values, whereas age, breed, and coat color were not. Conclusions: Most eyes evaluated are emmetropic, or shifted myopically, with excellent agreement between eyes of the same horse. Sex, iris color, and geographic location appear to impact refraction in horses. Support: None. [ABSTRACT FROM AUTHOR]

Purpose: To create a simplified model of the eye by which we can specify a key optical characteristic of the crystalline lens, namely its power. Methods: Cycloplegic refraction and axial length were obtained in 60 eyes of 30 healthy subjects at eccentricities spanning 40° nasal to 40° temporal and were fitted with a three‐dimensional parabolic model. Keratometric values and geometric distances to the cornea, lens and retina from 45 eyes supplied a numerical ray tracing model. Posterior lens curvature (PLC) was found by optimising the refractive data using a fixed lens equivalent refractive index (neq). Then, neq was found using a fixed PLC. Results: Eccentric refractive errors were relatively hyperopic in eyes with central refractions ≤−1.44 D but relatively myopic in emmetropes and hyperopes. Posterior lens power, which cannot be measured directly, was derived from the optimised model lens. There was a weak, negative association between derived PLC and central spherical equivalent refraction. Regardless of refractive error, the posterior retinal curvature remained fixed. Conclusions: By combining both on‐ and off‐axis refractions and eye length measurements, this simplified model enabled the specification of posterior lens power and captured off‐axis lenticular characteristics. The broad distribution in off‐axis lens power represents a notable contrast to the relative stability of retinal curvature. [ABSTRACT FROM AUTHOR]

Objectives. To provide a metric to differentiate between hyperopic and myopic ablation of a prior LASIK treatment based on the corneal pachymetry profile after laser vision correction (LVC). Methods. Pachymetry data were retrospectively recovered from patients who had previous LASIK for refractive purposes between 2019 and 2020. Patients with any corneal disorder were excluded. Ablation spherical equivalent was predicted from the central to semiperipheral corneal thickness (CPT) ratio, both values were provided by using the Pentacam user interface software (UI), and values were computed from extracted raw pachymetry data. Results. Data of 157 eyes of 81 patients were collected, of which data were analysed for 73 eyes of 73 patients to avoid concurrence of measurements in both eyes per subject (42% female; mean age 40.9; SD 12.8). The CPT ratio cutoff for distinction between myopic and hyperopic LASIK was 0.86 for Pentacam UI data. Sensitivity and specificity were 0.7 and 0.95, respectively. Accuracy increased with computation of the CPT ratio based on extracted raw data with sensitivity and specificity of 0.87 and 0.99, respectively. There was a marked linear correlation between the CPT ratio and the ablation spherical equivalent (R2 = 0.93). Conclusions. CPT ratio cutoffs can correctly classify if a cornea previously had a hyperopic versus myopic LASIK surgery and estimate the ablation spherical equivalent of such treatment. This could prove useful for increased accuracy of intraocular lens (IOL) calculations for patients with no historical data of their prior LVC surgery at the time of cataract surgery planning. [ABSTRACT FROM AUTHOR]

Background. To analyze the tolerance on distance vision of different combined residual astigmatic situations in patients implanted with a novel wavefront shaping extended depth of focus (EDoF) intraocular lens (IOL). Methods. The study included patients implanted with the Acrysof® IQ Vivity® IOL. Uncorrected (UDVA) and corrected distance visual acuity (CDVA) were measured three months after surgery, considering CDVA as the reference situation of the study. Distance VA was also measured in different refractive situations: (A) with 0.50 diopters (D) of positive (myopization) and negative (hyperopization) defocus and (B) with a residual mixed astigmatic refraction induced by adding a combination of −0.25 D spherical and 0.50 D cylindrical lenses placed in vertical (against the rule-ATR), oblique, and horizontal (with the rule-WTR) positions. Results. The study included 30 eyes of 30 patients. UDVA and CDVA were −0.04 ± 0.05 and −0.05 ± 0.05 logMAR, respectively. VA values with +0.50 D and −0.50 D of defocus were 0.01 ± 0.06 and 0.00 ± 0.04 logMAR, respectively. VA was better with distance correction (p < 0.001) and no differences were found between the myopic and the hyperopic situations (p = 0.09). Distance VA for the ATR, oblique, and WTR astigmatic situations was 0.01 ± 0.05, 0.01 ± 0.06, and 0.01 ± 0.04 logMAR, respectively. VA was better for the reference situation (p < 0.001) and no differences were found among the three astigmatic situations (p = 0.21). Conclusions. Low residual defocus and mixed astigmatic errors, regardless of its orientation, seem to be tolerated by patients implanted with the studied EDoF IOL. This trial is registered with NCT05392998. Registered 26 May 2022-Retrospectively registered. [ABSTRACT FROM AUTHOR]

Purpose: We used baseline data from the PICNIC longitudinal study to investigate structural, functional, behavioural and heritable metrics that may predict future myopia in young children. Methods: Cycloplegic refractive error (M) and optical biometry were obtained in 97 young children with functional emmetropia. Children were classified as high risk (HR) or low risk (LR) for myopia based on parental myopia and M. Other metrics included axial length (AXL), axial length/corneal radius (AXL/CR) and refractive centile curves. Results: Based on the PICNIC criteria, 46 children (26 female) were classified as HR (M = +0.62 ± 0.44 D, AXL = 22.80 ± 0.64 mm) and 51 (27 female) as LR (M = +1.26 ± 0.44 D, AXL = 22.77 ± 0.77 mm). Based on centiles, 49 children were HR, with moderate agreement compared with the PICNIC classification (k = 0.65, p < 0.01). ANCOVA with age as a covariate showed a significant effect for AXL (p < 0.01), with longer AXL and deeper anterior chamber depth (ACD) (p = 0.01) in those at HR (differences AXL = 0.16 mm, ACD = 0.13 mm). Linear regression models showed that central corneal thickness (CCT), ACD, posterior vitreous depth (PVD) (=AXL – CCT – ACD‐lens thickness (LT)), corneal radius (CR) and age significantly predicted M (R = 0.64, p < 0.01). Each 1.00 D decrease in hyperopia was associated with a 0.97 mm elongation in PVD and 0.43 mm increase in CR. The ratio AXL/CR significantly predicted M (R = −0.45, p < 0.01), as did AXL (R = −0.25, p = 0.01), although to a lesser extent. Conclusions: Although M and AXL were highly correlated, the classification of pre‐myopic children into HR or LR was significantly different when using each parameter, with AXL/CR being the most predictive metric. At the end of the longitudinal study, we will be able to assess the predictability of each metric. [ABSTRACT FROM AUTHOR]

Purpose: To give an overview of the misconceptions and potential artefacts associated with measuring peripheral refractive error and eye length, the use of these measures to determine the retinal shape and their links to myopia development. Several issues were identified: the relationship between peripheral refractive error and myopia development, inferring the retinal shape from peripheral refraction or eye length patterns, artefacts and accuracy when measuring peripheral eye length using an optical biometer. Methods: A theory was developed to investigate the influence of artefacts in measuring peripheral eye length and on using peripheral eye length to make inferences about retinal shape. Results: When determining peripheral axial length, disregarding the need to realign instruments with mounted targets can lead to incorrect field angles and positions of mounted targets by more than 10% for targets placed close to the eye. Peripheral eye length is not a good indicator of the effects of myopia or of treatment for myopia development because eyes of different lengths but with the same retinal shape would be interpreted as having different retinal shapes; the measurement leads to overestimates of changes in retinal curvature as myopia increases. Determining peripheral eye length as a function of estimated retinal height rather than field angle will halve the magnitude of the artefact. The artefact resulting from the peripheral use of biometers with an on‐axis calibration is modest and can be ignored. Conclusion: There are significant issues with peripheral measurements of the refractive error and eye length that must be considered when interpreting these data for myopia research. Some of these issues can be mitigated, while others require further investigation. [ABSTRACT FROM AUTHOR]

Purpose. To evaluate refractive outcomes, intraocular lens (IOL) power calculation, and IOL position following a novel conjunctiva-sparing transscleral fixation technique. Methods. Forty-one eyes of 40 patients managed with a flapless transscleral-sutured technique were included. Preoperative and postoperative refractive errors (spherical equivalents, SE) were compared. IOL position was assessed on the Scheimpflug images. IOL power was calculated by SRK/T, Holladay 1, and Hoffer Q formulas. Results. The mean age was 57.39 ± 14.83 years (range: 26 to 79 years), and the mean follow-up was 7.46 ± 6.42 months (range: 1 to 24 months). Surgical indications were aphakia (n = 14), subluxated lenses (n = 3), and IOL dislocation (n = 24). The SE was 4.50 ± 6.38 diopter (D) (range: −3.75 to 13.75 D) preoperatively and −1.68 ± 1.57 D (range: −5.50 to 1.13 D) postoperatively (P < 0.001). The mean tilt angle and decentration were 2.90° ± 1.93° (range: 0.39° to 9.10°) and 0.23 ± 0.19 mm (range: 0.02 to 0.94 mm) vertically, and 1.75° ± 1.41° (range: 0.24° to 7.65°) and 0.18 ± 0.19 mm (range: 0.02 to 1.06 mm) horizontally, which were clinically insignificant. All three IOL formulas produced myopic errors (range: −0.29 to −0.50 D). The SRK/T had the lowest median absolute error (0.55 D), followed by the Holladay 1 (0.70 D) and the Hoffer Q (0.74 D). The three formulas had the same percentage of prediction errors (PEs) within ±0.5 D (43.48%), while the Hoffer Q had the highest percentage of PEs within ±1.0 D (82.61%). Conclusion. The present technique can serve as an alternative approach for transscleral IOL fixation and refractive correction in eyes with compromised capsular support, ensuring the stability of IOLs and reasonable IOL power calculation accuracy. [ABSTRACT FROM AUTHOR]

Purpose: To determine the prevalence of refractive errors in a group of 8-year-old school children in northwestern Poland. Material and Methods: In 2017–2019, refractive errors were examined in a group of 1518 Caucasian children aged 8 years old with cycloplegia. Refraction was obtained with a hand-held autorefractor (Retinomax 3). The refractive error reading was expressed as the spherical equivalent (SE) as myopia (≤−0.5 D), emmetropia (>−0.5 D to ≤+0.5 D), mild hyperopia (>+0.5 D to ≤+2.0 D) and hyperopia (>+2.0 D), and astigmatism (≤−0.75 DC) and anisometropia (≥1.00 D). Data analysis was performed using Statistica 13.5 software and included Pearson's chi-squared and Mann–Whitney U tests. p-values of <0.05 were considered statistically significant. Results: Mild hyperopia was most common (37.6%), myopia was observed in 16.8% and astigmatism in 10.6% of participants. Pseudomyopia concerned up to 51.91% children. Girls were significantly more likely to have mild hyperopia (p = 0.0144) and were significantly more likely to wear glasses (p = 0.00093). Conclusions: Screening children for refractive errors after cycloplegia is key for detecting accommodative spasm and refractive errors. The largest group of children presented with mild hyperopia, which is a physiological feature of refraction in 8-year-old children, but myopia and astigmatism were the most common refractive errors. [ABSTRACT FROM AUTHOR]

Background: We aimed to investigate children with an emmetropic non-cycloplegic refraction (NCR) to compare the difference in progression of NC spherical equivalent (SE) over 2 years between the children with emmetropic and hyperopic cycloplegic refraction (CR) values. Methods: Through a retrospective medical record review, 59 children aged under 10 years were evaluated. Refractive error was calculated as the average of the SE values of both eyes. According to the CR results, children with emmetropia (-0.50 to 1.00 diopter [D]) were assigned to group 1 (n = 29), and those with hyperopia (≥ 1.00 D) were assigned to group 2 (n = 30). The prevalence of myopia and SE progression were compared over 2 years. Correlations between final SE progression and baseline age and refractive error were analyzed and multiple regression analysis was conducted. Receiver operating characteristic curves that achieved the best cutoff points to distinguish between the groups were calculated. Results: Group 1 showed significantly myopic SE changes compared to baseline at the 1-year follow-up, and group 1 was significantly myopic compared with group 2 at the 2-year follow-up. Myopia prevalence was 51.7% in group 1 and 6.7% in group 2 after 1 year, and 61.1% and 16.7% after 2 years, respectively. In the correlation analysis, baseline age, baseline CR, and difference between CR and NCR showed significant correlations with the 2-year SE progression (r = -0.359, p = 0.005; r = 0.450, p < 0.001; r = -0.562, p < 0.001, respectively). However, NCR refractive error showed no significant correlation (r = -0.097, p = 0.468). In multiple regression analysis, baseline age (β= -0.082), and CR-NCR difference (β= -0.214) showed a significant effect on SE progression for 2 years. When an NCR value of 0.20 D was set as the cut-off value to distinguish between the groups, a sensitivity of 70% and specificity of 92% were obtained. Conclusion: Even if NCR showed emmetropia, children with baseline CR values of emmetropia showed greater SE progression compared with those with hyperopia. Cycloplegia is essential to confirm the correct refractive status in children. It may be useful for predicting prognosis of SE progression. [ABSTRACT FROM AUTHOR]

Background: Globally, access to reliable, affordable tools that provide refractions and ultimately accurate spectacle prescriptions will aid in improving eye health. Our study aimed to evaluate a tele-optometric remote refraction compared to a traditional in-person subjective refraction. Methods: A cohort of 30 pre-presbyopic participants ≥18 years of age at the Illinois College of Optometry were recruited to participate in this pilot study. Participants completed two comprehensive eye examinations. First, the teleoptometric comprehensive eye examination was completed using the DigitalOptometrics platform. A remote technician completed refraction, followed by videoconferencing with an investigator optometrist. This remote eye examination was then followed by the in-person comprehensive eye examination by a different investigator optometrist, with a traditional manifest refraction. Both modalities used a Reichart VRx digital phoropter. Results: A total of 60 eyes were evaluated using both testing methods. The mean spherical equivalent, spherical power, cylindrical power, and axis in the tele-optometric remote refractions were -3.69 D ± 2.81 D, -3.35 D ± 2.68 D, -0.70 D ± 0.81 D, and 78 ± 77 degrees, respectively, compared to -3.58 D ± 2.80 D, -3.23 D ± 2.69 D, -0.68 D ± 0.71 D, and 81 ± 76 degrees in the in-person refraction group, respectively. No statistically significant difference was found between the spherical equivalent, spherical, cylindrical, and axis components of the prescriptions found in the tele-optometric examination compared to the in-person examination (p=0.82, p=0.82, p=0.93, p=0.85, respectively). Ten percent (6) of the eyes (4 hyperopic and 2 myopic) were over-minused in the tele-optometric examination. Conclusions: Using the DigitalOptometrics platform, tele-optometric remote refraction by a technician was not significantly different when compared to a traditional in-person manifest refraction in a young, healthy, pre-presbyopic adult-student cohort. Attention must be paid to low hyperopes and high myopes to ensure that they are not over-minused in remote refractions. [ABSTRACT FROM AUTHOR]

Background: This study aimed to compare anterior scleral thicknesses (ASTs) in people with emmetropia and myopia to explore the effect of myopia on AST. Methods: In this cross-sectional study, 93 participants (i.e., 93 eyes) with emmetropia and myopia underwent ocular imaging via anterior segment optical coherence tomography. We acquired raw B-scan OCT images along each of the four meridians (superior, inferior, nasal, and temporal), The AST was estimated from the limbus to a distance of 6 mm. The participants were aged between 20 and 50 years (mean age: 30.2 ± 8.8 years). The axial length (AL) was 22.50 ~ 33.04 mm (mean AL: 26.51 ± 2.65 mm), and the spherical equivalent (SE) was + 0.50 ~ 27.5 D (mean SE: −7.20 ± 6.5 D). The selected sample comprised 37 males and 56 females who were categorized as emmetropes, mild–moderate myopes, or high myopes. The four meridians of AST, AL, and refractive error were observed. Results: The AL was significantly negatively correlated with the four meridians of AST (the r value ranged between − 0.511 and − 0.228, P < 0.05). There was no significant correlation between age and inferior diameter (r = 0.113, P = 0.314), but age was positively correlated with the average AST of the superior, temporal, and nasal diameters (the r value ranged between 0.452 and 0.552, P < 0.05). There was no significant correlation between sex and AST (the T value ranged between − 1.816 and − 0.130, P > 0.05). Except for the inferior diameters of 1 mm, 5 mm, and 6 mm and the temporal diameter of 1 mm, the four diameters in the emmetropia group and the high myopia group were statistically significant at a distance of 0 ~ 6 mm from the limbus (P < 0.05). Conclusion: The AST is negatively correlated with AL and positively correlated with age. Compared with emmetropic eyes, the AST is thinner in highly myopic eyes. Myopia affects AST, which may be useful for monitoring progression in cases of myopia. [ABSTRACT FROM AUTHOR]

To determine the prevalence of refractive error (RE) and associated risk factors for myopic refractive errors in children and young adults from the urban region of Hyderabad, South India. Four thousand sixty-five (4,065) participants aged 6–22 years were enrolled and examined in this cross-sectional study conducted from October 2013 to January 2015. Participants were enrolled from a random sample of schools and universities in regions representative of urban Hyderabad. RE was determined using cycloplegic autorefraction. The association of demographic factors such as age, gender, and socio-economic category (SEC) (low/mid/high) with myopia was explored with logistic regression with robust standard error. Of the total participants, 2,259 were children aged 6–15 years and 1,806 were adolescents and young adults aged 16–22 years. Overall prevalence of myopia, high myopia (≤ −5.00D and ≤ −6.00 D), hyperopia, emmetropia, and astigmatism was 29.8% (95% CI: 26.0% to 33.6%, n = 1,216), 2.9% (95% CI: 1.9% to 3.9%, n = 120), 1.1% (95%CI: 0.7% to 1.5%, n = 46), 14.7% (95% CI: 12.4% to 17.0%, n = 599), 46.9% (95% CI: 43.7% to 50.1%, n = 1913) and 8.6% (95% CI: 7.4% to 9.9%, n = 352) respectively. A strong correlation existed between age and prevalence of myopia (R2 = 0.88, p <.001) and high myopia (R2 = 0.71, p <.001). Children from schools of low SEC (34.7%) had higher prevalence of myopia compared to the mid SEC (16.8%) (p =.043). Myopia was the most prevalent refractive error and increased with age in this urban population. More myopia was observed in schools of low SEC. [ABSTRACT FROM AUTHOR]

Introduction: Cataract affects nearly 9-12 million Indians annually after the age of 50 years. and, this exceeds glaucoma, macular degeneration, and diabetic retinopathy numbers combined. Cataract surgery is the most frequently performed surgery in India, with a success rate of nearly 98% and excellent visual rehabilitation. More than a million intraocular lenses (IOL) are implanted every year. Aims: A Comparative analysis of Recent Generation intraocular lens power calculation formulae to achieve emmetropia following Cataract surgery by phacoemulsification. Materials and methods: The present study was a prospective comparative study. This Study was conducted from October 2022 - February 2023 at Department of Ophthalmology, Venkateshwara Institute of Medical Sciences, Amroha (U.P). 120 patients were included in this study. Result: In our study for small eyes (< 20mm) Haigis group, the mean residual spherical refractive error was 0.68 ± 0.26 and in Holladay group, the mean residual refractive error was 0.83 ± 0.14 which was statistically significant (p=0.0008). In our study for normal eyes of Axial Length 20 to 24mm of in Haigis group the mean residual spherical refraction of the patients was -0.36 ± 0.80 and in Holladay group, the mean residual spherical refraction of the patients was 0.31 ± .63 which was statistically significant (p<0.0001). In our study for long eyes > 24mm of Axial length, In Haigis group the mean residual refractive error of large eye was -0.50 ± 0.00 and in Holladay group the mean residual error in large eye was 0.12 ± 0.64 which was not statistically significant (p=0.1189). Conclusion: we concluded that, prospective analysis of results showed that Comparing all four IOL formula we had found that in SMALL eyes, NORMAL eyes as well as in LARGE eyes The HOLLADAY IOL formula is having better result followed by HAIGIS. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of intraocular lens (IOL) power calculations among IOL formulas after phacovitrectomy. Methods: We prospectively enrolled 206 eyes of 206 patients who underwent 25-gauge phacovitrectomy, without gas tamponade, for macular pathology. Pre-operative optical biometry used the IOLMaster 700 to calculate the IOL power with the new formulas, i.e. the Barrett Universal II (BU II), Emmetropia Verifying Optical version 2.0, Hill-Radial Basis Function (RBF) version 3.0, Kane, and Ladas Super Formula, and conventional formulas, i.e. Haigis, Hoffer Q, Holladay 1, Holladay 2, and Sanders-Retzlaff-Kraff/T (SRK/T). A single-piece foldable IOL was implanted in all cases. Manifest refractions were measured before and 3 months after surgery. Results: The BU II formula showed the lowest standard deviation and mean and median absolute errors and had the highest percentage of eyes with a refractive prediction error within ± 0.25 D. The absolute error was significantly lower with the four new formulas, except the Hill-RBF, than with the Hoffer Q (all p = ≤ 0.010) and Holladay 1 formulas (all p = < 0.010). The absolute error with the BU II formula was also lower than that with the Holladay 2 (p = 0.012) and SRK/T (p = 0.024) formulas. Conclusion: Overall, the new IOL formulas, except the Hill-RBF, were superior to some of the conventional formulas for calculating IOL power in phacovitrectomy. [ABSTRACT FROM AUTHOR]

Purpose: To compare the stereoacuity in patients with anisometropia, isometropia, and emmetropia.Methods: A cross-sectional study was conducted on 1403 subjects (range: 5-45 years) divided into anisometropes (n = 403), isometropes (n = 500), and emmetropes (n = 500). There were 258 amblyopic eyes among anisometropes and 156 amblyopic eyes among isometropes. Stereoacuity was measured using the Titmus stereo test consisting of a combination of contour targets.Results: There were 675 males and 728 females. A significant (P < 0.001) reduction in stereoacuity was found in anisometropes as compared to isometropes and emmetropes. The stereoacuity was even worse in amblyopes as compared to non-amblyopes. Most patients with anisometropia of <3.0 D had fair stereoacuity. However, as the degree of anisometropia increased to >3.0 D, stereoacuity deteriorated gradually. Marked reduction of stereoacuity was observed in severe degree of anisometropia (>6.0 D). Overall, an anisometropia of ≥2.12 D was associated with reduced stereoacuity. Among the anisometropes, it was found to be the poorest in myopia, followed by myopia with astigmatism, hypermetropia with astigmatism, and hypermetropia.Conclusion: The level of stereoacuity was worse in anisometropes as compared to isometropes and emmetropes. Amblyopes had a greater reduction in stereoacuity than non-amblyopes. Stereoacuity decreased as the degree of anisometropia increased. Among the anisometropes, myopes had worst stereoacuity than hypermetropes. [ABSTRACT FROM AUTHOR]

Purpose: The final refraction after intraocular lens (IOL) implantation remains a challenge in the management of paediatric cataracts. No consensual guidelines exist for the choice of IOL power. The aim of this study was to validate a method of IOL power calculation by evaluating the final refractive error in all patients with IOL implantation operated at our institution. Methods: We retrospectively studied all children under 7 years of age who underwent cataract surgery with IOL implantation at our institution between 2010 and 2015. Intraocular lens (IOL) power was calculated as follows: After B‐scan determination of the emmetropic IOL power, a reduction of 40%, 35%, 30%, 25%, 20%, 15%, 10% and 5% was applied to children 0–3, 3–6, 6–12, 12–18, 18–24, 24–30, 30–36, 36–48 months, respectively. The following data were collected: follow‐up, age at surgery, uni‐ or bilaterality, implanted IOL power and final refraction. Results: During this period, 81 children (125 eyes) met the inclusion criteria with a median follow‐up of 60 months (36–97). The median age at surgery was 6.61 months (0.76–48). We included 52 children with bilateral cataract (96 eyes) and 29 children with unilateral cataract (29 eyes). The mean implanted IOL power was 23.3 ± 4.6 diopters (D). The mean spherical equivalent at last follow‐up was 0.07 ± 3.5 D. Conclusion: Our undercorrection formula for IOL implantation after congenital cataract surgery leads to long‐term refractive results globally close to emmetropia. [ABSTRACT FROM AUTHOR]

Objectives: Axial length (AL) is an important contributor to refraction, and growth curves are gaining importance in the prediction of myopia. This study aimed to profile the distribution of ocular biometry parameters and to identify correlates of spherical equivalent refraction (SE) among school children in South India. Materials and Methods: The School Children Ocular Biometry and Refractive Error study was conducted as part of a school screening program in southern India. The enrolled children underwent tests that included vison check, refraction, binocular vision assessment, and biometry measurements. Results: The study included 1382 children whose mean (standard deviation [SD]) age was 10.18 (2.88) years (range: 5-16 years). The sample was divided into 4 groups (grades 1-2, grades 3-5, grades 6-9, and grade 10) based on significant differences in right AL (p<0.001). The mean (SD) AL (range: 20.33-27.27 mm) among the four groups was 22.50 (0.64) mm, 22.88 (0.69) mm, 23.30 (0.82) mm, and 23.58 (0.87) mm, respectively. The mean SE (range: +1.86 to -6.56 D) was 0.08 (0.65 D) in class 1 and decreased with increasing grade to -0.39 (1.20 D) in grade 10. There was a significant difference in all biometry parameters between boys and girls (p<0.001). Age, AL, and mean corneal curvature were the main predictors of SE. Conclusion: This study provides a profile of ocular biometry parameters among school children in South India for comparison against profiles from other regions across the country. The study data will form a reference for future studies assessing myopia in this ethnicity. [ABSTRACT FROM AUTHOR]

Purpose: The effect of body mass index (BMI) and central fat distribution (CFD) reduction after bariatric surgery on ocular refraction is not well established. We assessed association between anthropometric parameters and refraction errors with other ocular and metabolic parameters 1 year after the surgery. Materials and Methods: This was a retrospective study with patients underwent bariatric surgery and had at least 1 year follow-up. Data were extracted from the bariatric and ophthalmology outpatient clinic records of the participants. Measurements of metabolic, anthropometric, and ocular parameters including BMI, CFD, refraction status, visual acuity, intraocular pressure (IOP), optic coherence tomography (OCT), and biometry test of the eyes were evaluated. Results: Seventy-four eyes of 37 patients had a mean follow-up of 14.4 ± 1.7 months after the surgery. Mean BMI and percentage of CFD decreased from 47.5 ± 6.7 to 33.1 ± 5.2 kg/m2 (p < 0.01) and 28.5 ± 5.74 to 17.8 ± 4.64 (p < 0.001) after 1 year, respectively. Mean refractive errors of the right and left eyes changed from − 0.62 ± 1.23 D to − 0.17 ± 1.36 D and from − 0.79 ± 1.39 to − 0.34 ± 1.56 after 1 year of the surgery (p < 0.001). Mean IOP was significantly reduced (p < 0.001). Unlike BMI, reduction in CFD was significantly correlated with refraction change in both eyes (right eyes; r = 0.783, left eyes; r = 0.791, p < 0.001) after 1 year. No significant differences were found in the other parameters. Conclusion: Bariatric surgery induced significant refractive change in eyes, which is significantly associated with CFD reduction after 1 year. Bariatric surgery should be considered as a risk factor in patients with unexpected refractive error changes. [ABSTRACT FROM AUTHOR]

To explore the relationship between binocular imbalance (BI) and the abnormal development of binocular refraction. BI data were collected by enrolling the first 1,000 adolescents and children aged 6–18 years in Shenzhen Eye Hospital from April 2020 to January 2021. In this cross-sectional study, the imbalance value (IV) did not show a statistical correlation with the spherical equivalent (SE) (oculus dexter [OD]: r = 0.022, p = 0.586; oculus sinister [OS]: r = −0.021, p = 0.606), and had little correlation with the uncorrected visual acuity (VA) (OD: r = −0.084, p = 0.039; OS: r = −0.034, p = 0.408). The proportion of binocular contrast imbalance (BCI) (the absolute value) maintained the highest level (from 54.42 to 79.17 percent) with the increase of bilateral SE difference in the four subcategories (binocular balance, monocular suppression, binocular rivalry, and BCI). From −100 to +100 of IV, the SE of the left eye tends to increase negatively when compared with the right eye (from −95 < IV ≦ −80, SE difference = −0.83 ± 1.58, to −20 < IV ≦ −10, SE difference = −0.14 ± 0.61; from 10 ≦ IV <20, SE difference = −0.05 ± 0.80, to 80 ≦ IV <95, SE difference = 1.48 ± 2.77). BI widely exists within the general pediatric population. The BI did not show significant correlation with the unilateral eye refractive state and the VA. However, the BI may be accompanied by imbalanced development of the eye refractive system. Furthermore, the SE of the dominant eye (from the prospective of BI) tends to be more negative than that of the opposite eye as the value increases. Clinical Trial Registration number: ChiCTR2100045457. [ABSTRACT FROM AUTHOR]

Introduction: A low-vision assessment (LVA) is critical in developing a vision rehabilitation plan. A remotely delivered LVA that replicates a standard in-clinic assessment may bridge the gap for patients not accessing care due to the limited quantity and distribution of low-vision providers. Within an LVA, an accurate and consistent assessment of refraction error is an essential component. No system has currently been validated for the purposes of a remote LVA. The purpose of this study was to validate a commercially available portable refraction approach in a low-vision population.Methods: Low-vision patients (n = 26) or normally sighted patients (n = 25) underwent a refraction assessment using the Adaptica® 2WIN autorefractor, adaptor scope (Kaleidos) and VisionFit phoropter portable refraction devices, as well as a standard autorefractor (Huvitz) and phoropter (Haag-Streit). Refraction data between systems and populations were compared using intraclass correlations. Bland-Altman plots were used to assess the differences between devices.Results: Spherical equivalent values were found to be reproducible between standard and experimental autorefraction devices (intraclass correlation coefficient (ICC) > 0.8) in both low-vision and normally sighted groups. Similarly, manifest refraction was highly consistent (ICC > 0.8) between devices in all groups. The Bland-Altman plots showed clinically acceptable mean differences of 0.701 between autorefraction methods and -0.116 between manifest refraction methods.Discussion: The 2WIN/VisionFit system can reliably generate refraction values across a spectrum of errors in normally sighted and visually impaired people, and would be feasible to deliver remotely. [ABSTRACT FROM AUTHOR]

We compared ultrasonic ocular axial length and vitreous chamber depth, and physical anthropometry in normal and myopic African adults due to sparse related data in this setting. This was a hospital-based, case-control study in which 175 myopes and 175 emmetropes, recruited by convenience sampling, at General Hospital Epe, Lagos, had their anthropometry and refractive status determined; and ocular axial length and vitreous chamber depth measured with A- and B-mode ocular ultrasonography. Data was analyzed using appropriate inferential statistics and level of significance set at 0.05. Mean ocular axial length in normal, mild, moderate and severe myopia was 22.45mm, 23.54mm, 23.79mm, and 25.56mm while mean vitreous chamber depth in normal, mild, moderate, and severe myopia was 15.45mm, 16.63mm, 16.84mm, and 18.68mm, respectively. Males had significantly longer axial length and vitreous chamber depth than females. Correlation between weight, height and BMI and refractive status among myopes was insignificant. There was consistency between A- and B-mode ultrasonography ocular axial length and vitreous chamber measurements with a Cronbach's Alpha of 0.888 and 0.842, respectively (p<0.001). Ocular axial length and vitreous chamber depth increased with the severity of myopia with no correlation of anthropometry with refractive status among African myopes. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this study is to evaluate and compare the accuracy of Barrett Universal II versus third-generation formula for different intraocular lens (IOL) powers for Indian eyes with different axial lengths (ALs). DESIGN: This is a retrospective, nonrandomized consecutive case series. METHODS: This study reviewed 981 eyes from 825 patients who had uneventful cataract surgery and IOL implantation. The eyes were separated into subgroups based on AL as follows: short (<22.0 mm), medium (22.01-23.99 mm), and long (>24.0 mm). The predicted refractive outcome using formulas was calculated and compared with the actual refractive outcome to give the prediction error. The percentage of every refractive error absolute value for each formula was calculated at <±0.50D, 0.50D-0.75D, and >±0.75D. RESULTS: In all, 981 eyes were analyzed. There were no significant differences in the median absolute error predicted by Barrett and the third-generation formulae. The Barrett Universal II formula resulted in significantly lowest mean spherical equivalent in short eyes (P = 0.0047) as well as a higher percentage of eyes with prediction errors within <±0.50D, 0.50D-0.75D, and >±0.75D. We found that the Barrett Universal II formula had the lowest predictive refraction error and mean absolute error across all ALs. CONCLUSION: The Barrett Universal II formula rendered the lowest predictive error compared with SRK/T, Holladay, and Hoffer Q formulas. Thus, the Barrett Universal II formula may be regarded as a more reliable formula for achieving emmetropia and reducing postoperative refractive surprises across all ALs. [ABSTRACT FROM AUTHOR]