Search

PURPOSE: To assess the effect of residual sphere on vision and satisfaction in pseudophakic patients. SETTING: Private clinics, United Kingdom. DESIGN: Retrospective case series. METHODS: A multivariate model evaluated the effect of 1-month residual sphere on outcomes of pseudophakic patients. Odds ratios (ORs) were calculated to assess the relative risk of not achieving ≥20/20 monocular uncorrected distance visual acuity (UDVA), ≥20/50 uncorrected near visual acuity (UNVA), and not being satisfied with vision. ORs were assessed for residual sphere -1.00 to +1.00 diopter (D) in quarter-diopter steps, using 0.00 D as a reference. RESULTS: The analysis included 38 828 multifocal and 11 571 monofocal intraocular lenses (IOLs). The residual myopic sphere ≤-0.25 D and hyperopic sphere ≥+0.50 D had a clinically meaningful effect on UDVA. Although monofocal IOLs had an improvement in UNVA with every additional 0.25 D of myopia, the change in ORs with increasing myopia was not significant for multifocal IOLs. The mean improvement in UNVA comparing eyes with 0.00 D and -1.00 D sphere was 0.26 logMAR for monofocal and 0.03 logMAR for multifocal IOLs. Low near-addition IOLs had a slightly higher gain in UNVA with increasing myopia, but the gain was not as substantial as with monofocal IOLs. The effect of ametropia on satisfaction was more pronounced for multifocal IOLs. For every 0.25 D of residual myopia, there was >25% increase in dissatisfied patients. CONCLUSIONS: Although myopia improved UNVA in eyes with monofocal IOL, multifocal IOLs did not benefit from residual myopia. Multifocal IOL patients desiring distance vision should be targeted closest to emmetropia, even if it means targeting slight hyperopia.

PURPOSE: To assess the accuracy of intraoperative wavefront aberrometry (IWA) versus modern intraocular lens formulas in post-myopic laser vision correction (LVC) patients undergoing cataract surgery with capsular tension ring placement. METHODS: This is a retrospective chart review conducted at an academic outpatient center. All post-myopic LVC eyes undergoing cataract surgery with IWA from a single surgeon from 05/2017 to 12/2019 were included. All patients received a capsular tension ring (CTR). Mean numerical error (MNE), median numerical error (MedNE), and percentages of prediction error within 0.50D, 0.75D, and 1.00D were calculated for the above formulas. RESULTS: Twenty-seven post-myopic LVC eyes from 18 patients were included. In post-myopic LVC, MNE with Optiwave Refractive Analysis (ORA), Barrett True K (BTK), Haigis, Haigis-L, Shammas, SRK/T, Hill-RBF v3.0, and W-K AL-adjusted Holladay 1 were + 0.224, - 0.094, + 0.193, - 0.231, - 0.372, + 1.013, + 0.860, and + 0.630 (F = 8.49, p

BACKGROUND: Plusoptix photoscreeners are capable of measuring refractive errors of children from 1 meter distance, without cyloplegia. We aimed to compare refractive data obtained from the newest version of Plusoptix (model 12) with cycloplegic autorefraction. METHODS: We examined 111 consecutive children aged 3-7 years first by Plusoptix A12C under manifest condition and subsequently for cycloplegic refraction by Topcon KR-1 tabletop autorefractometer. Sphere, spherical equivalent, cylinder and axis of astigmatism measured by the two methods were analyzed to determine correlation, agreement and differences. RESULTS: Binocular examination of 111 children aged 4.86±1.27 years revealed good agreement between refractive data obtained by Plusoptix and cycloautorefraction, according to Bland-Altman plots. Significant (p < 0.001) and strong correlation was found between all refractive measurements (Pearsons r value of 0.707 for sphere, 0.756 for pherical equivalent, and 0.863 for cylinder). Plusoptix mean sphere, spherical equivalent and cylinder were 1.22, 0.56, and -1.32 D, respectively. Corresponding values for cycloautorefraction were 1.63, 1.00, and -1.26 D. The difference between axis of cylinder measured by the two methods was < 10° in 144 eyes (64.9%). CONCLUSIONS: Considering the significant agreement and correlation between Plusoptix photoscreener and cycloplegic autorefraction, the need for cycloplegic drops in refractive examination of children may be obviated. The mean difference between cylinder measurements are considerably trivial (0.06 D), but sphere is approximately 0.4 D underestimated by Plusoptix compared to cycloautorefraction, on average.

Purpose: To conduct a large retrospective study of screening refractive error in young children. Methods: This retrospective study included children aged from 4 months to 8 years in Daxing District, Beijing, who underwent refractive examinations without cycloplegia. It included a cross‐sectional assessment of refractive error screening for all children, and a longitudinal component for a subgroup with data available for two to five visits. Results: A total of 14,987 children were included in the cross‐sectional study. In the group <1 year of age, the percentage of children with a spherical equivalent (SE) >+2.00 D or with cylinder <−1.50 D was 15.25% and 33.24%, respectively. These were significantly higher than for the 1‐ to 4‐year‐old group (SE 8.1% higher, cylinder 13.2% higher) (χ2 = 53.57, p < 0.001; χ2 = 790.39, p < 0.001). Furthermore, 34.83% of children in the 0‐year‐old group had amblyopia risk factors (ARFs). In the 4‐year‐old group, boys had a significantly longer axial length (AL) than girls (differences in the right and left eyes were 0.53 and 0.56 mm, respectively; z = 5.48 p < 0.001, z = 5.80, p < 0.001). AL increased with age, while the AL difference between boys and girls remained stable at 4–8 years of age. The percentage of children aged 5–8 years with myopia in 2020–2021 was significantly higher than that in 2018–2019 (H = 12.44, p = 0.006). In the longitudinal study of 4406 children (up to 12‐month follow‐up), annual changes in SE were −0.27, −0.06, 0.19 and 0.13 D between 0 and 3 years, and −0.38, −0.58, −0.70 and −0.75 D between 5 and 8 years. Conclusions: Children's refractive error varied significantly from ages 4 months to 1 year, with a high proportion having ARFs. Children aged 5–8 years showed a trend towards myopia. The prevalence of myopia in the cross‐sectional analysis in 2020–2021 was greater than in 2018–2019. Screening refraction changed minimally over a 12‐month period for children aged 1–3 years, but became more myopic for children aged 5–8 years. [ABSTRACT FROM AUTHOR]

Purpose: Uncorrected refractive error is the leading cause of vision impairment globally; however, little attention has been given to equity and access to services. This study aimed to identify and prioritise: (1) strategies to address inequity of access to refractive error services and (2) population groups to target with these strategies in five sub‐regions within the Western Pacific. Methods: We invited eye care professionals to complete a two‐round online prioritisation process. In round 1, panellists nominated population groups least able to access refractive error services, and strategies to improve access. Responses were summarised and presented in round 2, where panellists ranked the groups (by extent of difficulty and size) and strategies (in terms of reach, acceptability, sustainability, feasibility and equity). Groups and strategies were scored according to their rank within each sub‐region. Results: Seventy five people from 17 countries completed both rounds (55% women). Regional differences were evident. Indigenous peoples were a priority group for improving access in Australasia and Southeast Asia, while East Asia identified refugees and Oceania identified rural/remote people. Across the five sub‐regions, reducing out‐of‐pocket costs was a commonly prioritised strategy for refraction and spectacles. Australasia prioritised improving cultural safety, East Asia prioritised strengthening school eye health programmes and Oceania and Southeast Asia prioritised outreach to rural areas. Conclusion: These results provide policy‐makers, researchers and funders with a starting point for context‐specific actions to improve access to refractive error services, particularly among underserved population groups who may be left behind in existing private sector‐dominated models of care. [ABSTRACT FROM AUTHOR]

Purpose: The study investigated the effect of capsular tension ring (CTR) implantation on postoperative refractive stability and accuracy of intraocular lens (IOL) formulas for axial length (AL) ≥ 27.0 mm patients. Methods: Prospective case series. The eyes of patients underwent phacoemulsification extraction combined with IOL implantation were classified as CTR implantation (A-CTR) and without CTR implantation (B-CON) groups. Refractive outcome and anterior chamber depth (ACD) were recorded at 1 week, 1 month, and 3 months post-operation. Prediction refractive error (PE) and absolute refractive error (AE) of each formula were calculated. Results: A total of 89 eyes (63 patients) were included and randomized into the CTR (A-CTR) and control groups (B-CON). Comparison of refraction at different postoperative times of the CTR group showed no statistical difference (all P > 0.05). The ACD in the A-CTR group gradually deepened, and that in the B-CON group gradually shallowed (all P > 0.05). The formulas' AE showed statistically significant differences in CTR and CON groups (P < 0.001). The PE of Hill-RBF 2.0 and EVO formulas in the A-CTR group were more hyperopic than that in the B-CON group (all P > 0.05), the other five formulas were more myopic in A-CTR group than that in the B-CON group (all P > 0.05). Conclusion: Patients with 13 mm diameter CTR implantation tended to have stable refraction at 1 week post-surgery and 1 month for those without it. CTR of the 13 mm diameter had no effect on the selection of formulas. Additionally, it is found that Kane and EVO formulas were more accurate for patients with AL ≥ 27.0 mm. [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]

The spin Hall effect of light, a phenomenon characterized by the transverse and spin dependent splitting of light at an optical interface, is highly promising for collecting precise quantitative data from interfaces and stands as an appealing option for improving precision metrology. This high level of precision is attributed to the principles of weak measurement. Since its conceptual introduction, the spin Hall effect of light has been empirically observed through weak measurement techniques, adhering closely to the initially proposed experimental configuration. Recently, it has been suggested that the setup can be downsized without compromising precision. Here, the first experimental demonstration of "compact weak measurement" is achieved by observing the spin Hall effect of both reflected and refracted light. Compared to the conventional weak measurement, this compact setup performs the same measurements but requires less free space by replacing the two convex lenses with a set of concave and convex lenses. The compact weak measurement demonstrates excellent agreement with theoretical predictions and experimental findings from traditional setups across both isotropic–isotropic and isotropic–anisotropic interfaces. The experimental validation of the compact configuration paves the way for the practical application of the spin Hall effect of light in devices with a smaller form factor. [ABSTRACT FROM AUTHOR]

Individuals with Down syndrome are known to have a greater prevalence of ocular conditions such as strabismus, nystagmus, elevated refractive error, poor accommodative function, elevated higher‐order optical aberrations and corneal abnormalities. Related to these conditions, individuals with Down syndrome commonly have reduced best‐corrected visual acuity at both far and near viewing distances across their lifespan. This review summarises the various optical sources of visual acuity reduction in this population and describes clinical trials that have evaluated alternative spectacle prescribing strategies to minimise these optical deficits. Although refractive corrections may still have limitations in their ability to normalise visual acuity for individuals with Down syndrome, the current literature provides evidence for eye care practitioners to consider in their prescribing practices for this population to maximise visual acuity. These considerations include accounting for the presence of elevated higher‐order aberrations when determining refractive corrections and considering bifocal lens prescriptions, even for young children with Down syndrome. [ABSTRACT FROM AUTHOR]

Waveform inversion is theoretically a powerful tool to reconstruct subsurface structures, but a usually encountered problem is that accurate sources are very rare, causing the computation to be unstable or divergent. This challenging practical problem, although sometimes ignored and even imperceptible, can easily create discrepancies in calculated shot gathers, which will then lead to wrong residuals that will be smeared back to the gradients, hence jeopardizing the inverted tomograms. For any real dataset, every shot gather corresponds to its unique source even if some gathers can be transformed alike after data processing. To resolve this problem, we propose a collocated inversion of sources and early arrival waveforms with the two submodules executing successively. Not only can this method reconstruct a decent source wavelet that approaches the ground truth, but also it can produce credible background tomograms with optimized sources. Part of the cycle skipping problems can also be mitigated because it avoids the trial and error experiments on various sources. Numerical tests on a synthetic and a land dataset validate the effectiveness of this method. Restrictions on initial sources or starting velocity models will be relaxed, and this method can be extended to any other applications for engineering or exploration purposes. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusions Demands for myopia management are rising. A web‐based tool that allows home‐performed self‐assessments of visual acuity (VA) and refractive error may enable hybrid care pathways and aid in identifying those with deteriorating visual performance. The tool has been validated in adult populations, but has yet to be evaluated in children. This study compared home‐performed VA and refraction self‐assessments to conventional measurements obtained at the clinic in a population of myopic children.Myopic children aged ≥6 years old were invited to perform web‐based eye tests at home, assisted by a parent. At two myopia control clinics, they also underwent measurements of VA using a Snellen chart and refractive error using cycloplegic autorefraction. Agreement between the tests, repeatability of the web‐based test and associations between clinical characteristics and web‐based test accuracy were evaluated.A total of 147 children were enrolled, of whom 116 (51% male; mean age 13 ± 3 years; mean spherical equivalent refraction (SEQ) −5.58 ± 3.05) performed the web‐based tests at home. Overall, the home‐performed VA self‐assessment and the Snellen chart assessment at the clinic agreed well (mean difference 0.03 ± 0.11 logMAR). A significant proportional bias was identified (β 0.65, p < 0.001), indicating underestimated web‐based VA scores when the child's vision declined. The sensitivity to detect VA poorer than 0.10 logMAR was 94%; the specificity was 71%. The web‐based refractive error algorithm measured more myopia progression compared to clinic observations (mean difference SEQ 0.40 ± 0.51 dioptres). Age, sex or use of atropine drops were not significantly associated with test accuracy.The web‐based test for self‐assessing vision, performed at home by children with assistance from their parents, yielded VA scores with a precision similar to Snellen chart testing conducted in a clinical setting. However, the web‐based refractive error algorithm overestimated myopia progression and requires recalibration for this specific age group. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion To estimate the prevalence of amblyopia and refractive errors among 6‐year‐old children in Greenland and to assess the impact of incorporating autorefraction, stereoacuity and near visual acuity testing into vision screening.In this cross‐sectional study, 517 children (238 girls and 279 boys) from 21 locations in Greenland were screened using HOTV charts for distance and near visual acuity (VA), stereoacuity test and non‐cycloplegic autorefraction. Referral criteria for further ophthalmological examination included a VA of ≥0.2 logMAR on the worse‐seeing eye or an interocular VA difference of ≥2 lines.Initial screening identified amblyopia (defined as VA of ≥0.3 logMAR) in 7% (unilateral) and 3% (bilateral) of children. However, subsequent ophthalmological examinations confirmed amblyopia in under 40% of referrals. Significant interocular VA differences were found in 9%. The prevalence of refractive errors at the screening was 3% for myopia (≤−0.5 dioptres), 10% for hyperopia (>+2.0 dioptres) and 14% for astigmatism (≤−1.00 dioptres), while the corresponding prevalences at the ophthalmological examination were 4% for myopia, 8% for hyperopia and 6% for astigmatism. Combining screening measurements increased the positive predictive values, thereby enhancing screening accuracy. Specifically, the incorporation of autorefraction or stereoacuity with distance VA demonstrated to be the most effective combination. Six percent of the children were prescribed glasses after the screening procedure.This study provides the first visual profile of Greenlandic schoolchildren. Incorporating autorefraction, stereoacuity and near visual acuity in vision screenings enhanced the efficacy of detection of vision anomalies. Although this may lead to more false positives, accurate screening is crucial in regions with limited ophthalmological resources. [ABSTRACT FROM AUTHOR]

The ultrashort radio wave refraction in the troposphere depends on meteorological conditions. In the present study, an atmospheric-soil measuring complex is used to measure the meteorological parameters at altitudes of 1 and 10 m for three years (2015–2017), and refraction gradients are calculated at standard meteorological times. Monthly datasets are grouped depending on the time of day to illustrate their typical diurnal behavior. The obtained data sub-arrays are analyzed using descriptive statistics. The occurrence of super-refraction is observed in the second half of day at the lake coast during the summer period. [ABSTRACT FROM AUTHOR]

Reflectance spectroscopy has emerged as a powerful analytical technique in the field of dermatology, offering a non-invasive strategy to assess several cutaneous properties and skin response to topical products. By analyzing reflected light across different wavelengths, reflectance spectroscopy allows the quantification of cutaneous parameters, such as erythema index and melanin content. Moreover, this analytical technique enables the monitoring of any changes in skin physiology facilitating the assessment of long-term effects of topical products as well as predicting cutaneous diseases. This review provides an overview of the application of reflectance spectroscopy in investigating skin properties and reaction to topical applied products, including both pharmaceutical and cosmetic formulations, thereby aiding in the development of personalized solutions tailored to individual needs. [ABSTRACT FROM AUTHOR]

Determining the axial length (AL) of the eye is of significant interest in the management of myopia. However, the devices that allow this value to be obtained are either expensive, for example, optical biometers, or inconvenient for use in pediatric population, such is the case with ultrasound biometers. Therefore, this study aimed to develop a mathematical model for estimating the AL value based on easily obtainable variables, with the novel addition of body height to the analysis. A total of 170 eyes of 85 myopic volunteers (mean age of 10.8 ± 1.45 years, ranging from 7 to 14 years) were included in the analysis. Participants underwent anamnesis, keratometry by NVISION-K 5001, subjective refraction by an optometrist, AL measurement by the Topcon MYAH biometer, and body height measurement. Spearman's correlation test was employed to analyze the relationships between AL and keratometry, spherical equivalent, body height (Sperman's correlation, all r ≥ 0.267, all p < 0.001), and age (Spearman's correlation, p = 0.081). Subsequently, multiple regression analysis was conducted on the variables that demonstrated a previous correlation. The mathematical model obtained permits the estimation of AL based on average keratometry, spherical equivalent, and body height. This model is significant (p < 0.001) and explains 82.4% of AL variability. [ABSTRACT FROM AUTHOR]

AIM: To examine the effects of blepharoplasty on the ocular surface and refractive state.METHODS:Retrospective study. A total of 70 patients(108 eyes)who underwent blepharoplasty in our ophthalmology department from January 2022 to June 2023 were selected, among which 40 cases(48 eyes)diagnosed with ptosis received levator muscle shortness, and 30(60 eyes)diagnosed with eyelid laxity/single eyelids received blepharoplasty. The ocular surface disease index(OSDI), tear meniscus height(TMH), Schirmer Ⅰ test(SⅠt), tear film break-up time(BUT), corneal fluorescein staining(FL), cylindrical(Cyl), surface regularity index(SRI), surface asymmetry index(SAI), keratometry(Km), and cylindrical(C).RESULTS:There were statistical differences in preoperative and postoperative OSDI, BUT, SⅠt, and FL of patients who received levator resection(all P0.05). At 1 mo postoperatively, OSDI, BUT, SⅠt, and FL were significantly different compared to preoperative values(all P0.05). No significant differences were found in Cyl, SRI, SAI, Km, or C in either group before and after surgery(all P>0.05).CONCLUSION:The levator resection has an early impact on the ocular surface of patients with ptosis, and corneal protection measures should be taken early. There was no significant impact on patients undergoing blepharoplasty; there was no significant effect on the refractive status of all patients.

Abstract Purpose The study investigated the effect of capsular tension ring (CTR) implantation on postoperative refractive stability and accuracy of intraocular lens (IOL) formulas for axial length (AL) ≥ 27.0 mm patients. Methods Prospective case series. The eyes of patients underwent phacoemulsification extraction combined with IOL implantation were classified as CTR implantation (A-CTR) and without CTR implantation (B-CON) groups. Refractive outcome and anterior chamber depth (ACD) were recorded at 1 week, 1 month, and 3 months post-operation. Prediction refractive error (PE) and absolute refractive error (AE) of each formula were calculated. Results A total of 89 eyes (63 patients) were included and randomized into the CTR (A-CTR) and control groups (B-CON). Comparison of refraction at different postoperative times of the CTR group showed no statistical difference (all P > 0.05). The ACD in the A-CTR group gradually deepened, and that in the B-CON group gradually shallowed (all P > 0.05). The formulas’ AE showed statistically significant differences in CTR and CON groups (P 0.05), the other five formulas were more myopic in A-CTR group than that in the B-CON group (all P > 0.05). Conclusion Patients with 13 mm diameter CTR implantation tended to have stable refraction at 1 week post-surgery and 1 month for those without it. CTR of the 13 mm diameter had no effect on the selection of formulas. Additionally, it is found that Kane and EVO formulas were more accurate for patients with AL ≥ 27.0 mm.

Abstract 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.

Wearable optics have a broad range of uses, for example, in refractive spectacles and augmented/virtual reality devices. Despite the long-standing and widespread use of wearable optics in vision care and technology, user discomfort remains an enduring mystery. Some of this discomfort is thought to derive from optical image minification and magnification. However, there is limited scientific data characterizing the full range of physical and perceptual symptoms caused by minification or magnification during daily life. In this study, we aimed to evaluate sensitivity to changes in retinal image size introduced by wearable optics. Forty participants wore 0%, 2%, and 4% radially symmetric optical minifying lenses binocularly (over both eyes) and monocularly (over just one eye). Physical and perceptual symptoms were measured during tasks that required head movement, visual search, and judgment of world motion. All lens pairs except the controls (0% binocular) were consistently associated with increased discomfort along some dimension. Greater minification tended to be associated with greater discomfort, and monocular minification was often-but not always-associated with greater symptoms than binocular minification. Furthermore, our results suggest that dizziness and visual motion were the most reported physical and perceptual symptoms during naturalistic tasks. This work establishes preliminary guidelines for tolerances to binocular and monocular image size distortion in wearable optics.

AIM: To analyze the abnormal refractive status of infants and young children aged 6 to 48 months, and to provide basis for the correction of ametropia and the early prevention and treatment of amblyopia.METHODS: Infants and young children aged 6 to 48 months were examined for refraction by Spot vision screener for natural optometry. Clinical data of infants and young children with refractive abnormalities were collected, Ciliary muscle paralysis agent was used for retinoscopy and optometry, and the results were statistically analyzed.RESULTS: A total of 168 cases(336 eyes)with abnormal Spot refractive outcomes were collected, with a high proportion of hyperopia and astigmatism abnormalities, 38.4% and 28.6%, respectively, while the proportion of myopia was low(12.2%). There were 90 cases of anisometropia(≥1.00 D), among which 41 cases(45.6%)were astigmatic anisometropia, 33 cases(36.7%)were hyperopic anisometropia, and 16 cases(17.8%)were myopic anisometropia, accounting for the least proportion. A total of 109 infants and young children with Spot refractive abnormalities completed ciliary muscle paralysis retinal optometry. The analysis of the difference and correlation between Spot diopter and post ciliary muscle paralysis optometry results showed that the difference in astigmatism was 0.34±0.64 D(P

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 crosscylinder 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.

Propagation‐based phase contrast, for example in the form of edge enhancement contrast, is well established within X‐ray imaging but is not widely used in neutron imaging. This technique can help increase the contrast of low‐attenuation samples but may confuse quantitative absorption measurements. Therefore, it is important to understand the experimental parameters that cause and amplify or dampen this effect in order to optimize future experiments properly. Two simulation approaches have been investigated, a wave‐based simulation and a particle‐based simulation conducted in McStas [Willendrup & Lefmann (2020). J. Neutron Res.22, 1–16], and they are compared with experimental data. The experiment was done on a sample of metal foils with weakly and strongly neutron absorbing layers, which were measured while varying the rotation angle and propagation distance from the sample. The experimental data show multiple signals: attenuation, phase contrast and reflection. The wave model reproduces the sample attenuation and the phase peaks but it does not reproduce the behavior of these peaks as a function of rotation angle. The McStas simulation agrees better with the experimental data, as it reproduces attenuation, phase peaks and reflection, as well as the change in these signals as a function of rotation angle and distance. This suggests that the McStas simulation approach, where the particle description of the neutron facilitates the incorporation of multiple effects, is the most convenient way of modeling edge enhancement in neutron imaging. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to investigate the distribution of spherical equivalent and axial length in the general population and to analyze the influence of education on spherical equivalent with a focus on ocular biometric parameters. Methods: The Gutenberg Health Study is a population-based cohort study in Mainz, Germany. Participants underwent comprehensive ophthalmologic examinations as part of the 5-year follow-up examination in 2012–2017 including genotyping. The spherical equivalent and axial length distributions were modeled with gaussian mixture models. Regression analysis (on person-individual level) was performed to analyze associations between biometric parameters and educational factors. Mendelian randomization analysis explored the causal effect between spherical equivalent, axial length, and education. Additionally, effect mediation analysis examined the link between spherical equivalent and education. Results: A total of 8532 study participants were included (median age: 57 years, 49% female). The distribution of spherical equivalent and axial length follows a bi-Gaussian function, partially explained by the length of education (i.e., < 11 years education vs. 11–20 years). Mendelian randomization indicated an effect of education on refractive error using a genetic risk score of education as an instrument variable (− 0.35 diopters per SD increase in the instrument, 95% CI, − 0.64–0.05, p = 0.02) and an effect of education on axial length (0.63 mm per SD increase in the instrument, 95% CI, 0.22–1.04, p = 0.003). Spherical equivalent, axial length and anterior chamber depth were associated with length of education in regression analyses. Mediation analysis revealed that the association between spherical equivalent and education is mainly driven (70%) by alteration in axial length. Conclusions: The distribution of axial length and spherical equivalent is represented by subgroups of the population (bi-Gaussian). This distribution can be partially explained by length of education. The impact of education on spherical equivalent is mainly driven by alteration in axial length. [ABSTRACT FROM AUTHOR]

The subject of this paper is the radiative transfer in media with refractive index gradients. Asymptotic expressions of the intensity distributions in the vicinity of singular directions are derived. Critical conditions for the occurrence of singular intensity distributions in fields of scattered radiation in a medium are formulated. It is shown that singular radiation fields in such media can be generated, among other things, by nonsingular configurations of radiation sources. The obtained results are verified by direct comparison with the results of numerical calculations using the Monte Carlo statistical modelling method. [ABSTRACT FROM AUTHOR]

Purpose: To describe the benefits of optometric evaluation for detection of vision-affecting conditions in the context of community-based eye health screenings and identify factors associated with having a recent dilated eye exam. Methods: Enrolled participants were age 40 and older, living independently in affordable housing developments in New York City. Eye health screening failure and criteria for seeing the on-site study optometrist were defined as visual acuity 20/40 or worse in either eye, intraocular pressure 23–29 mmHg, or an unreadable fundus image. The optometrist conducted a manifest refraction using loose lenses and used a portable slit lamp and ophthalmoscope to perform a non-dilated anterior and posterior segment ocular health evaluation. Demographics, social determinants of health, eye health screening results, and rates of suspected ophthalmic conditions were recorded. To determine factors associated with having a recent dilated eye exam, which was the main outcome for this statistical analysis, a stepwise multivariate logistic regression was performed. Results: A total of 708 participants were screened, 308 attended the optometric exam; mean age 70.7 ± 11.7 [standard deviation (SD)] years. Among this subgroup, 70.1% identified as female, 54.9% self-identified as African American, 39% as Hispanic/Latino, and 26.6% Dominican ethnicity; 78.2% (241/308) had not undergone a dilated eye exam within the last year, 71.4% reported they did not have an eye care provider. Stepwise multivariate logistic regression analysis indicated that participants who self-reported having cataracts (odds ratio (OR) 2.15; 95% confidence interval (CI) 1.03–4.47; p = 0.041), self-reported having glaucoma/glaucoma suspect (OR 5.60; 95% CI 2.02–15.43; p = 0.001), or spoke Spanish as their primary language (OR 3.25; 95% CI 1.48–7.11; p = 0.003) had higher odds of having a recent dilated eye exam. Conclusions: This community-based screening initiative demonstrated the effectiveness of optometric exams in detecting vision-affecting conditions and identified factors associated with having a recent dilated eye exam. Optometrists play a vital role in increasing access to eye care for high-risk, underserved populations. Trial registration: ClinicalTrials.gov (NCT04271709). [ABSTRACT FROM AUTHOR]

Copyright of Knowledge: International Journal is the property of Institute for Knowledge Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Refractometric studies of hydrosols containing diamond nanoparticles have been carried out in this work. The samples for the study have been obtained from a statically synthesized diamond powder preliminarily subjected to standard purification by washing with strong acids and sonication. After additional repeated washing, centrifugation, sonication, and settling for a month, samples, whose particles contained different fractions of amorphous carbon, have been obtained. The particle size in the obtained samples was smaller than 100 nm. To analyze the data of refractometric measurements, equations have been derived that make it possible to determine the fraction of amorphous carbon in the particles and to calculate the thickness of its layer on the particle surface from the results of studying the refractive index and density of the sols of diamond particles. The data of the refractometric studies have been used to determine the ratios between the fractions of crystalline diamond and amorphous carbon in the particles. The performed studies have shown that the refractometric analysis of particle composition can be used to control the quality of industrially produced nanodiamonds. [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]

The permittivity of a material is an important parameter to characterize the degree of polarization of a material and identify components and impurities. This paper presents a non-invasive measurement technique to characterize materials in terms of their permittivity based on a modified metamaterial unit-cell sensor. The sensor consists of a complementary split-ring resonator (C-SRR), but its fringe electric field is contained with a conductive shield to intensify the normal component of the electric field. It is shown that by tightly electromagnetically coupling opposite sides of the unit-cell sensor to the input/output microstrip feedlines, two distinct resonant modes are excited. Perturbation of the fundamental mode is exploited here for determining the permittivity of materials. The sensitivity of the modified metamaterial unit-cell sensor is enhanced four-fold by using it to construct a tri-composite split-ring resonator (TC-SRR). The measured results confirm that the proposed technique provides an accurate and inexpensive solution to determine the permittivity of materials.

PurposeThe purpose of this study was to evaluate the epidemiology, etiology, clinical assessment, investigation, management, and visual consequences of high myopia (≤-6 diopters [D]) in infants and young children.FindingsHigh myopia is rare in pre-school children with a prevalence less than 1%. The etiology of myopia in such children is different than in older children, with a high rate of secondary myopia associated with prematurity or genetic causes. The priority following the diagnosis of high myopia in childhood is to determine whether there is an associated medical diagnosis that may be of greater overall importance to the health of the child through a clinical evaluation that targets the commonest features associated with syndromic forms of myopia. Biometric evaluation (including axial length and corneal curvature) is important to distinguishing axial myopia from refractive myopia associated with abnormal development of the anterior segment. Additional investigation includes ocular imaging, electrophysiological tests, genetic testing, and involvement of pediatricians and clinical geneticists is often warranted. Following investigation, optical correction is essential, but this may be more challenging and complex than in older children. Application of myopia control interventions in this group of children requires a case-by-case approach due to the lack of evidence of efficacy and clinical heterogeneity of high myopia in young children.ConclusionsHigh myopia in infants and young children is a rare condition with a different pattern of etiology to that seen in older children. The clinical management of such children, in terms of investigation, optical correction, and use of myopia control treatments, is a complex and often multidisciplinary process.

Human visual function depends on the biological lens, a biconvex optical element formed by coordinated, synchronous generation of growth shells produced from ordered cells at the lens equator, the distal edge of the epithelium. Growth shells are comprised of straight (St) and S-shaped (SSh) lens fibers organized in highly symmetric, sinusoidal pattern which optimizes both the refractile, transparent structure and the unique microcirculation that regulates hydration and nutrition over the lifetime of an individual. The fiber cells are characterized by diversity in composition and age. All fiber cells remain interconnected in their growth shells throughout the life of the adult lens. As an optical element, cellular differentiation is constrained by the physical properties of light and its special development accounts for its characteristic symmetry, gradient of refractive index (GRIN), short range transparent order (SRO), and functional longevity. The complex sinusoidal structure is the basis for the lens microcirculation required for the establishment and maintenance of image formation.

Purpose: To investigate the refractive and ocular biometric characteristics of children with mild hyperopia and distinguish between non-myopic and pseudomyopic eyes before cycloplegia. Methods: The eligible children underwent refractive error measurements using a NIDEK autorefractor before and after the administration of 0.5 % tropicamide. Ocular biometric parameters, including axial length (AL), anterior chamber depth (ACD), and lens thickness (LT), were measured using the IOLMaster 700 before cycloplegia. We performed comparative analyses between the non-myopic and pseudomyopic groups, categorized based on whether the spherical equivalent (SE) before cycloplegia exceeded −0.50 diopters (D). Univariable and multivariable regression analyses were performed to control for confounding factors. Results: The final analysis included 968 eyes. The participants with pseudomyopia were more likely to be boys (P = 0.029), younger (P = 0.004), less hyperopic (P

Background: Phacoemulsification stands as the most commonly conducted ocular procedure. Biometry represents an art with numerous generations of formulas introduced to enhance refractive prediction accuracy. The Sanders Retzlaff Kraff theoretical (SRK/T), a third-generation formula that merges linear regression and a theoretical eye model, and the Kane formula, a fourth-generation formula incorporating theoretical optics, regression, and artificial intelligence, embody our focal points. Our aim is to compare post-operative refractive outcomes utilizing SRK/T and Kane formulae for calculating intraocular lens (IOL) power in senile cataract patients undergoing phacoemulsification featuring a hydrophilic acrylic, monofocal IOL. Methods: This prospective, interventional institutional study engaged 70 patients, totaling 74 eyes. They were categorized into two groups: Group A employed the SRK/T for IOL power calculation, while Group B used the Kane formula. Quantel Medical® A-scan biometer was employed. A comparison was drawn between both formulae in terms of mean absolute error (MAE) and median absolute error (MedAE), with the utilization of IBM SPSS 20 and a significance level of p

Background/objectivesWe provide global averages and standard deviations for ocular biometry-axial length (AL), corneal radius of curvature (CR), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), and central corneal thickness (CT). We hope a better understanding of normal and abnormal values will help clinicians gain further insight into their surgical outcomes, especially for off-target eyes.Subjects/methodsWe searched the MEDLINE database using keywords "axial length, corneal power, anterior chamber depth, lens thickness, white to white, and corneal thickness." We included studies that reported averages and standard deviations on eye biometry for at least 1300 eyes. Global weighted averages and standard deviations were calculated using the Cochrane method.ResultsFourteen studies were included, originating from Asia (Japan, Singapore, Myanmar, Iran, South Korea, China), Europe (Germany, United Kingdom, Portugal), Australia, and North America (United States). Global ocular biometry metrics were: AL-23.49 mm ± 1.35 mm, CR-7.69 mm ± 0.28 mm, ACD-3.10 mm ± 0.47 mm, WTW-11.80 mm ± 0.42 mm, LT-4.37 mm ± 0.43 mm, and CT-544 μm ± 38 μm. Total eyes per value ranged from 19,538 to 90,814.ConclusionsWe report global ocular biometry averages and standard deviations. No eyes were from studies in Africa or South America, highlighting the need to publish eye biometry data from these continents. We hope that promoting a deeper understanding of biometry values will help clinicians gain insight into surgical outcomes and drive innovations in lens calculations.

Purpose: to compare the refractive error measurements achieved through three distinct techniques: retinoscopy, subjective method, and the subjective fogging method. Methods: Participants included 223 young adults aged 18 to 36 years (mean age: 25.63±5.31). The refractive error of one eye was measured under three different accommodation control conditions: subjective refraction, fogging subjective refraction and retinoscopy.Results: Data were collected for 223 young adults. The average Spherical value obtained by the retinoscopy method was 0.21 and the average cylinder was -0.76. These values were -0.01 and -0.75, respectively, in the subjective with fog method: The Spherical value and cylinder obtained by the regular subjective method were -0.13 and -0.74 D, respectively; The mean spherical equivalent with subjective refraction method was more minus than fogging subjective refraction and retinoscopy provided the most plus results. the difference in spherical and spherical equivalent value between three methods was significant (p- value< 0.001) but the difference in cylindrical value between three groups was not significant (p- value> 0.05). According to the Intraclass Correlation Coefficient analysis, the agreement between three methods for measuring sphere (ICC= 0.99), cylinder (ICC= 0.95) and spherical equivalent (ICC= 0.99) was good.Conclusions: The results showed that retinoscopy and fogging subjective refraction were the most similar methods, with a small mean difference. However, the comparison between retinoscopy and subjective refraction had wider limits of agreement than retinoscopy and fogging subjective refraction. Key words: Retinoscopy, subjective, refraction, fogging

Abstract Aim To investigate the correlation of angles α and κ with the refractive and biological parameters in children. Methods This case-series study included 438 eyes of 219 children (males/females = 105/114, age: 3–15 years). Ocular biometric parameters, including axial length, corneal radius of curvature (CR), white-to-white distance (WTW), angle κ and angle α, were measured using IOL Master 700; auto-refraction were assessed under cycloplegia. The eyes were assigned to different groups based on CR, WTW, and gender to compare the angles α and κ, and analyze the correlations between the differences of biological parameters on angles α and κ. Results The means of axial length, CR, WTW, angle α, and angle κ were 23.24 ± 1.14 mm, 7.79 ± 0.27 mm, 11.68 ± 0.41 mm, 0.45 ± 0.25 mm, and 0.27 ± 0.22 mm, respectively. Angle α was correlated with CR and WTW (fixed effect coefficient [FEC] = 0.237, p = 0.015; FEC = -0.109, p = 0.003; respectively), and angle κ also correlated with CR and WTW (FEC = 0.271, p = 0.003; FEC = -0.147, p

Jacob David Schaafsma,1 Robert W Arnold2 1School of Medicine, University of Milan, Milan, Italy; 2Alaska Blind Child Discovery, Alaska Children’s EYE & Strabismus, Anchorage, AK, USACorrespondence: Robert W Arnold, Alaska Blind Child Discovery, Alaska Children’s EYE & Strabismus, 3500 Latouche Street &num;280, Anchorage, AK, 99508, USA, Tel +1(907)561-1917, Fax +1(907)563-5373, Email eyedoc@alaska.netBackground: Seeking a quick way to estimate refractions for challenging pediatric patients, we studied two non-contact methods with particular attention to accuracy and level of stress in uncovering cycloplegic hyperopia.Methods: Newly referred and follow-up pediatric eye patients had timed school bus accommodation-relaxing skiascopy (SBARS) and Plusoptix A12 (Px) photoscreener testing before cyclopentolate 1% confirmatory examinations. The ABCD ellipsoid univariate method based on relative blur and vector components was used to compare dry sphero-cylinder refraction estimates with cycloplegic. Receiver operating characteristic (ROC) curves were used to determine screening value.Results: Three compared refractions were attempted in 191 racially diverse children of whom 100 were age 0.2– 3.9 years and 91 were 4 to 14 years. Plusoptix failed to yield a result in 21 and an additional 21 were interpreted as an excess sphere. Median spherical equivalent did not differ between Px and SBARS for 149 with Px readings but in hyperopic patients, Plusoptix uncovered 27% less hyperopia. The ellipsoid for SBARS of 0.8 was better than 2.4 for Plusoptix (Mann–Whitney p< 0.001). Plusoptix was fastest (3– 15 seconds) followed by SBARS (15– 30 seconds) compared to 30– 45 minutes for cycloplegic exam.Conclusion: Non-contact quick refractive methods enhanced confirmatory cycloplegic pediatric exam in high-risk pediatric patients.Keywords: sphero-cylinder, refraction, autorefraction, photoscreening, developmental delay