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Objectives: To evaluate the impact of upper eyelid blepharoplasty on contrast sensitivity in dermatochalasis patients. Materials and Methods: Best corrected visual acuity, ophthalmologic examination, eyelid examination, lash ptosis, contrast sensitivity using sine-wave contrast sensitivity chart, keratometric parameters, and corneal aberrations of 34 eyes of 34 patients who underwent upper eyelid blepharoplasty due to dermatochalasis in our clinic between the years 2014 and 2018 were evaluated preoperatively and at postoperative 3 months. Results: Twenty-three (68%) of the patients were females and 11 (32%) were males. Mean age was 63.1±7 (52-81) years. Mean best corrected visual acuity was 0.036±0.06 (0-0.15) logMAR preoperatively and postoperatively (p>0.05). Contrast sensitivity values of the patients at the frequencies of 1.5, 3, 6, 12, and 18 cycles per degree were 44.38±19.5, 59.03±27.2, 41.44±34.1, 15.15±19.3, and 5.15±4.26 preoperatively and 44.80±20.9, 76.85±33.4, 63.21±46.4, 28.21±31.1, and 10.5±9.5 postoperatively, respectively. The difference between contrast sensitivity values was statistically significant at the frequencies of 3, 6, 12, and 18 cpd (p = 0.005, =0.001, <0.001, and <0.001, respectively). Although lash ptosis of the patients improved significantly after the surgery, there was no correlation between lash ptosis improvement and change in contrast sensitivity (p>0.05). Keratometric values and corneal high order aberrations did not change significantly after the surgery (p>0.05). Conclusion: Contrast sensitivity significantly increases after upper eyelid blepharoplasty, especially at higher spatial frequencies which are known to deteriorate due to age-related changes in the lens and retina in older adults. Our results show that blepharoplasty may have additional functional indications for elderly dermatochalasis patients in terms of improving the functions such as performing daily tasks and reading. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature 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.)

Background: This study sought to assess the impact of classifying keratoconus location based on thinnest pachymetry or maximum keratometry (Kmax) on progression parameters after corneal crosslinking (CXL).Methods: In this observational study, patients were followed up at one, three, six and 12 months after CXL. All patients underwent visual acuity, Scheimpflug tomography and slitlamp assessment at all follow-ups. Keratoconus was classified as central, paracentral and peripheral based on X and Y co-ordinates of either thinnest pachymetry (Group 1) or Kmax (Group 2). Progression parameters Kmax, ABCD grading, anterior, posterior and total wavefront (WF) aberrations were compared between the groups.Results: Fifty-two eyes (43 patients) were classified into Groups 1 and 2: there were 82.8 per cent, 13.4 per cent, 3.8 per cent and 42.3 per cent, 38.4 per cent, 19.2 per cent central, paracentral and peripheral cones respectively. Central cones: Group 1: 'C' decreased after three months, Kmax, 'A', anterior and total WF decreased after six months. Group 2: Kmax, anterior and total WF decreased after three months, 'A' decreased at 12 months, whereas 'C' increased from three months. Paracentral cones: Group 1: no significant changes. Group 2: Kmax and 'A' decreased after six months, 'C' increased after three months. Peripheral cones: Group 1: no significant changes. Group 2: 'C' increased only at one month.Conclusion: Thinnest pachymetry and Kmax should not be used interchangeably when categorising keratoconus. Although keratoconus may have thin cornea centrally, the Kmax may not be central. For the majority of parameters considered for monitoring progression, changes were noticed earlier when the keratoconus was classified based on Kmax. [ABSTRACT FROM AUTHOR]

PURPOSE: The current study was performed to analyze the prevalence and presentation patterns of corneal astigmatism types in cataract surgery candidates. METHODS: Preoperative corneal astigmatism were prospectively measured with Autokeratometer in 780 patients (1018 eyes) during the year (2018) in cataract surgery (phacoemulsification) candidates. Descriptive and analytical statistics of astigmatism severity and keratometric data were performed based on age and sex. RESULTS: A total of 1018 eyes of 780 patients were included in the present study, of which 445 (57.1%) were female and 335 (42.9%) were male. Of the 1018 evaluated eyes, 590 (58%) were female and 428 (42%) were male. The mean age of the patients was determined as 65.88 ± 11.43 years. The mean flat and steep-axis keratometric values were recorded as 44.75 ± 1.86 D and 43.82 ± 1.69 D, respectively. Women showed significantly steeper corneas. Based on LOCS III system, the types of cataracts were as follows: Posterior subcapsular 37.4%, nuclear 28%, cortical 1%, and mixed 33.6%. Types of astigmatism were as follows: 34.7% with-the-rule (WTR), 29.3% against-the-rule (ATR), 35.3% oblique and 0.7% had no astigmatism. A significant relationship of the type of astigmatism with gender and age group was observed (P <0.001), where the prevalence of WTR and ATR were found to be higher among women and men, respectively. The prevalence of WTR was higher among lower age groups, while the prevalence of ATR was found to be higher among older age groups. Furthermore, 70.8% of the eyes revealed astigmatism of at least 0.5 diopters, followed by astigmatism of at least 1 diopter (33.6%), astigmatism of at least 1.5 diopters (16.2%0, and astigmatism of at least 2 diopters (9.2%). CONCLUSIONS: The Findings showed a significant prevalence of astigmatism greater than one diopters in these patients. The results of the study could provide valuable data for cataract surgeons and IOL manufacturers regarding the prevalence and type of corneal stigmatism. [ABSTRACT FROM AUTHOR]

To determine the changes in keratometry measurements and refraction in patients having the thermo-mechanical periorbital skin treatment, Tixel®, to treat dry eye disease (DED). A multi-centre, prospective, non-masked study was conducted. DED patients were recruited in 3 international centres and were evaluated in 5 visits separated by an interval of 2 weeks except for the last visit which took place after 18 weeks from visit 1. The same clinical examination was performed at all visits: OSDI questionnaire, tear stability, keratometry, best corrected visual acuity and refraction. Tixel® treatment was applied at the first 3 visits. 89 participants (24 males/65 females; mean age: 55.0 ± 14.2 years) were included: 20 presented moderate DED symptoms and 69 severe DED symptoms. Significant differences were found for the spherocylindrical refraction (vector analysis) between visit 1 and visits 2 and 3. Following cumulative analysis, 11.86 % and 16.94 % of participants had more than 0.5 dioptre (D) change in mean keratometry and keratometric astigmatism, respectively, at 3 months post-treatment. A total of 5.40 % had a sphere and cylinder change greater than 0.50D and 16.21 % had the axis changed more than 10 degrees (vector analysis). These changes were particularly significant in patients with severe DED symptoms. Keratometry readings and refraction can change following thermo-mechanical skin treatment for DED, especially in those patients with severe DED symptoms. This should be considered as potential errors in intraocular lens calculations may be induced. [ABSTRACT FROM AUTHOR]

This study aimed to assess the anterior corneal wavefront aberrations, keratometry, astigmatism vectors and pupil size between Pentacam HR® (Oculus Optikgeraete GmbH, Wetzlar, Germany) and iTrace® (Tracey Technologies Corp., Houston, TX, USA). In this observational study, 100 eyes (50 healthy volunteers) were scanned in mesopic light condition with a Pentacam HR® and iTrace®. Anterior corneal aberrations (spherical aberration (Z40), vertical coma (Z3 − 1), horizontal coma (Z3 + 1)), keratometry in the flattest (K1) and steepest meridian (K2), mean astigmatism, astigmatic vectors (J0 and J45), and pupil size were measured. We found a significant difference in Z40 (Pentacam®: +0.30 ± 0.11 µm and iTrace®: −0.03 µm ± 0.05 µm; p < 0.01) with no correlation between the devices (r = −0.12, p = 0.22). The devices were in complete agreement for Z3 − 1 (p = 0.78) and Z3 + 1 (p = 0.39), with significant correlation between the machines (r = −0.38, p < 0.01 and r = −0.6, p < 0.01). There was no difference in K1, K2 and mean astigmatism. J0 was negative with both devices (against-the-rule astigmatism), but there was no correlation. J45 was negative with the Pentacam HR® (more myopic oblique astigmatism) but significantly correlated between the devices. Pupil size was smaller with Pentacam HR® (p < 0.01). In summary, these devices cannot be used interchangeably. Corneal Z40 was significantly different with more negative Z40 with iTrace® compared to Pentacam HR®. iTrace® operates with lower illumination, giving larger pupil size than Pentacam HR®, which uses intense blue light during measurement. No correlation was found for J0. Pentacam HR® had a trend to record more negative J45 (myopic oblique astigmatism).

AIM: To compare the corneal curvature and to investigate the agreement between three different keratometers.METHODS: In this prospective study, keratometry was performed using an IOL Master(IM), a Bausch & Lomb manual keratometer(Man)and TOPCON KR-8800 autokeratometer(Top)on 252 eyes of patients recruited from camps for cataract surgery. The average keratometry values were recorded and compared. The agreements between the instruments were analyzed using the Bland-Altman statistical method. The main outcome measure was average keratometry values.RESULTS:1)IOL Master and Manual keratometer: the mean corneal power was 44.62±1.52 D with the IOL Master and 44.60±1.52 D with the Manual keratometer. The paired t-test demonstrated a statistically significant difference in the mean corneal power between the IOL Master and Manual keratometer(P=0.001). The 95% LOAs of the two devices were -0.22 to 0.22 as shown in the Bland-Altman plot; 2)IOL Master and autokeratometer: the mean corneal power was 44.62±1.52 D with the IOL Master and 44.46±1.53 D with the autokeratometer. The paired t-test demonstrated a statistically significant difference in the mean corneal power between the IOL Master and autokeratometer(Pttest demonstrated a statistically significant difference in the mean corneal power between the autokeratometer and Manual keratometer(PCONCLUSION: Keratometry data obtained with different instruments may not be interchangeable, a fact that has important implications for cataract surgeons with respect to both surgical planning and outcomes auditing.

INTRODUCTION: A comparison of precision of intraocular implant power calculation by computing keratometry values by two different methods, namely, the automated and manual keratometry (MK), was done. For checking this accuracy, the parameter taken into consideration was the absolute refractive error which was ascertained postoperatively. SUBJECTS AND METHODS: This study was conducted in the Department of Ophthalmology, Sri Aurobindo Institute of Medical Sciences and PG Institute, Indore. At a tertiary eye care centre in Central India (Sri Aurobindo Institute of Medical Sciences, Indore). Duration of the study was 18 months. Sample size was 66 individuals who were with cataract (nuclear sclerosis I to III). Although keratometry was done by both methods and implant power derived separately by computing both readings, decision of which power to be implanted in an eye would depend on the group, in which patient would fall. Group A were prospective candidates who would be implanted intraocular lens (IOL) of that power as assessed by computing MK value, whereas Group B were participants who would be implanted IOL of that power as assessed by computing value obtained by automated keratometry (AK). First patient fell in Group A and second in Group B, third again in Group A till 33 patients had been operated in each group. RESULTS: Bland–Altman plot thus obtained showed that the two keratometers are comparable. The postoperative refractive errors for the two Groups (A and B), showed that if an error of ±0.50 D or less is considered, then in Group A 81% of patients achieved this and 87% of patients required this as spectacle aid in Group B. CONCLUSIONS: In this study, we compared the accuracy of AK with that of MK for calculation of implant power. It was concluded from this study that AK is a simple keratometric technique that appeared to be more accurate than MK.

Tiago B Ferreira, Filomena J Ribeiro Department of Ophthalmology, Hospital da Luz, Lisbon, Portugal Purpose: To assess the comparability and repeatability of keratometric and astigmatism values measured by four techniques: Orbscan IIz® (Bausch and Lomb), Lenstar LS 900® (Haag-Streit), Cassini® (i-Optics), and Total Cassini (anterior + posterior surface), in healthy volunteers.Patients and methods: Fifteen healthy volunteers (30 eyes) were assessed by the four techniques. In each eye, three consecutive measures were performed by the same operator. Keratometric and astigmatism values were recorded. The intraclass correlation coefficient (ICC) was used to assess comparability and repeatability. Agreement between measurement techniques was evaluated with Bland–Altman plots.Results: Comparability was high between all measurement techniques for minimum keratometry (K1), maximum keratometry (K2), astigmatism magnitude, and astigmatism axis, with ICC >0.900, except for astigmatism magnitude measured by Cassini compared to Lenstar (ICC =0.798) and Orbscan compared to Lenstar (ICC =0.810). However, there were some differences in the median values of K1 and K2 between measurement techniques, and the Bland–Altman plots showed a wide data spread for all variables, except for astigmatism magnitude measured by Cassini and Total Cassini. For J0 and J45, comparability was only high for J0 between Cassini and Orbscan. Repeatability was also high for all measurement techniques except for K2 (ICC =0.814) and J45 (ICC =0.621) measured by Cassini.Conclusion: All measurement techniques showed high comparability regarding K1, K2, and astigmatism axis. Although posterior corneal surface is known to influence these measurements, comparability was high between Cassini and Total Cassini regarding astigmatism magnitude and axis. However, the wide data spread suggests that none of these devices should be used interchangeably. Keywords: astigmatism, keratometry, topography, repeatability, comparability

Objective: To describe the distribution of the central corneal thickness (CCT) measurements on a healthy Hispanic sample population and its correlation with age, mean simulated keratometry (SimK), and mean refractive spherical equivalent (MRSE). Methods: Retrospective analysis on the records of healthy patients from the Ophthalmology and Visual Sciences Institute, Tecnologico de Monterrey, January 2015 to August 2015. CCT data, age, gender, corneal curvature, and spherical equivalent was obtained. A descriptive analysis and correlation by the Spearman method was performed. The sample was divided by age subgroups: than 40 years old and correlation analysis with CCT values was determined. Results: A total of 93 (186 eyes) patients were included. Mean age: 32.54 ± 12.04 years. 43% were women. Mean CCT: 545.69 ± 36.88 μm, mean SimK: 43.56 ± 1.90 D and MRSE: −2.54 ± 3.15 D. No correlation was registered between CCT and the variables when analyzed with the Anderson–Darling (p = 0.006), Shapiro–Wilk (p = 0.043), and Kolmogorov–Smirnov (p = 0.01). CCT showed a bimodal distribution with higher density at 540 μm. Age groups 40 years showed significant difference in CCT (p = 0.016), a positive correlation with CCT was observed in the group

Purpose: To evaluate the effect of phaco-trabeculectomy in the presence of primary open-angle glaucoma (POAG) and cataract on the anterior segment parameters. Material and Methods: We included the POAG cases with cataract who had underwent combined phaco-trabeculectomy to this retrospective study. The age, sex, preoperative and postoperative 6th month visual acuity (VA) according to LogMAR, intraocular pressure (IOP) measured by Goldmann applanation tonometer, keratometry values (K), central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), and anterior chamber angle (ACA) measured with corneal topography were recorded. Results: Sixteen (29.62%) of the patients were female, 38 (70.37%) were male. The average age was 61.6±15.1 (28-83). The VA was 0.7±0.2 in the preoperative period and 0.47±0.1 in the postoperative 6th month according to the logMAR (p<0.05). The mean IOP was measured as 35.5±12 mmHg under maximum medical treatment in the preoperative period, and was measured as 11.7±2.9 mmHg without any treatment in the postoperative 6th month (p=0.00). During follow-up, none of the patients had increased IOP at the level that required medical treatment. There were no signifi cant differences in K values, CV and CCT between the preoperative and postoperative 6th months' values (p>0.05). ACD and ACA showed a signifi cant increase in the postoperative period (p=0.00, p<0.029). Conclusion: Combined phaco-trabeculectomy led to an increase in the mean visual acuity as well as effective IOP reduction. In addition, changes in anterior segment parameters were shown in the postoperative period in patients undergoing phaco-trabeculectomy, and it was thought that this may have effects on refraction and IOP. [ABSTRACT FROM AUTHOR]

Purpose: Anecdotal reports of refractive changes in pregnancy are familiar to optometrists and ophthalmologists. Refractive stability during pregnancy has implications in both prescribing of refractive correction and candidacy for refractive surgery. This study aims to examine refractive status in a nationally representative sample of US pregnant women. Methods: The National Health and Nutrition Examination Survey (NHANES) is a weighted, stratified, cross-sectional survey of the US population conducted every 2 years. During 2005–2006 and 2007–2008, the exam included multiple ophthalmic tests including refraction, keratometry, and lensometry. Female participants aged 20–44 years with available vision examination data were included in the study. Subjects were excluded if best obtainable visual acuity was worse than 20/40 or there was prior history of cataract or refractive surgery. The primary outcome was defined as refractive change stratified by trimester of pregnancy. Results: 301 pregnant women were matched with 301 nonpregnant controls based on age, ethnicity, and education. There was no difference in refractive error between pregnant women and matched nonpregnant controls (all p > 0.99). For the refractive change analysis, a subgroup of 60 pregnant subjects with glasses at presentation was matched to 60 nonpregnant controls. Multivariate regression showed a significant increase in refractive change versus prior to glasses prescription by trimester of pregnancy (p = 0.02), though this change was not in a specific direction (i.e., no significant shift toward either myopia or hyperopia). Conclusions: Pregnant women have greater refractive difference from prior spectacle prescription later in pregnancy, but the direction of this change is variable and not significant. This finding may reflect a longer time to last glasses prescription later in pregnancy, given concerns that refractive error fluctuates in pregnancy. Additional longitudinal studies are needed to better characterize the effects of pregnancy on refractive status. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Optometry is the property of Elsevier B.V. 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.)

Purpose: Keratoconus is an ectatic eye disease characterized by progressive thinning and steepening of the cornea which leads to irregular astigmatism and visual function loss. Determination of choroidal thickness in keratoconus patients may help us to better understand and manage the keratoconus disease. Choroidal thickness may be a potential marker for disease activity in keratoconus patients. In this study, we aimed to determine choroidal thickness in keratoconus patients and compare the results with the age-matched control group. Methods: This is a prospective study with a control group. Keratometry and thinnest corneal thickness was measured and recorded in keratoconus patients. Choroidal thickness of all subjects was measured using an optical coherence tomography device (Spectralis OCT, version 6.0, Heidelberg Engineering, Germany) with an enhanced depth imaging mode without pupil dilation. Mean choroidal thickness of keratoconus patients was compared with healthy subjects. Results: One hundred and sixty eyes of 80 healthy subjects and 160 eyes of 80 keratoconus patients were included in the study. Mean thinnest corneal thickness of the keratoconus patients was 449.7 ± 3.2 microns. Mean corneal keratometry value and cylindrical refraction error in the keratoconus patients were 53.2 ± 0.2 and 3.3 ± 0.1 diopters, respectively. Mean choroidal thickness was 363.9 ± 59.8 and 328.4 ± 67.2 microns in keratoconus patients and healthy subjects, respectively. There was a very significant difference between keratoconus patients and healthy subjects in terms of choroidal thickness (P = 0.000). There was not a statistically significant correlation between choroidal thickness and thinnest corneal thickness in keratoconus patients (P = 0.814). Conclusion: Choroidal thickness was found to be increased in keratoconus patients. Choroidal thickness could potentially become a new clinical marker for disease activity in keratoconus patients [ABSTRACT FROM AUTHOR]

The understanding of correlations between different biometric parameters is essential for personalized eye care in the field of cataract and refractive surgery. This systematic review offers a clear overview of the previous literature assessing these correlations including a meta‐analysis. The review is focused on the following five correlations: (1) axial length and refractive error; (2) anterior chamber depth and refractive error; (3) axial length and anterior chamber depth; (4) corneal power and refractive error; (5) corneal power and axial length. An expected strong correlation between axial length and refractive error was found. Correlations including corneal power were weak and might be clinically insignificant. [ABSTRACT FROM AUTHOR]

Purpose: To compare the refractive outcomes following cataract surgery using conventional keratometry (K) and total keratometry (TK) for intraocular lens (IOL) calculation in the SRK/T, HofferQ, Haigis, and Holladay 1 and 2, as well as Barrett and Barrett TK Universal II formulas. Methods: Sixty eyes of 60 patients from Siriraj Hospital, Thailand, were prospectively enrolled in this comparative study. Eyes were assessed using a swept-source optical biometer (IOLMaster 700; Carl Zeiss Meditec, Jena, Germany). Posterior keratometry, K, TK, central corneal thickness, anterior chamber depth, lens thickness, axial length, and white-to-white corneal diameter were recorded. Emmetropic IOL power was calculated using K and TK in all formulas. Selected IOL power and predicted refractive outcomes were recorded. Postoperative manifest refraction was measured 3 months postoperatively. Mean absolute errors (MAEs), median absolute errors (MedAEs), and percentage of eyes within ± 0.25, ± 0.50, and ± 1.00 D of predicted refraction were calculated for all formulas in both groups. Results: Mean difference between K and TK was 0.03 D (44.56 ± 1.18 vs. 44.59 ± 1.22 D), showing excellent agreement (ICC = 0.99, all p < 0.001). Emmetropic IOL powers in all formulas for both groups were very similar, with a trend toward lower MAEs and MedAEs for TK when compared with K. The Barrett TK Universal II formula demonstrated the lowest MAEs. Proportion of eyes within ± 0.25, ± 0.50, and ± 1.00 D of predicted refraction were slightly higher in the TK group. Conclusions: Conventional K and TK for IOL calculation showed strong agreement with a trend toward better refractive outcomes using TK. The same IOL constant can be used for both K and TK. [ABSTRACT FROM AUTHOR]

Purpose: To assess corneal power measurements obtained by the OPD SCAN III Topographer in eyes with prior myopic small incision lenticule extraction (SMILE) surgery. Methods: Sixty untreated myopic eyes of sixty subjects and forty previous myopic SMILE surgery eyes of forty subjects were consecutively enrolled in the present study. Manifest refraction, OPD SCAN III and Pentacam HR were performed. Keratometric measurements assessed by OPD SCAN III—simulated keratometry, average pupil power and effective central corneal power (ECCP) were compared with mean keratometry (Km) obtained by Pentacam HR in the untreated group and the clinical history method (CHM) in the treated group. Results: In the untreated group, no statistically significant differences were revealed between all corneal power measurements obtained with OPD SCAN III and Km. In the treated group, all the corneal power measurements were statistically different from the CHM except for the Haigis method and the Shammas method, while ECCP had a statistically but not clinically significant overestimation of 0.42 D with 95% limit of agreement (LOA) of − 0.81 D to 1.64 D. The three modified ECCP had better prediction performance with narrower 95% of LOA lying in (− 1.20, 1.20 D) (− 1.22, 1.23 D) and (− 0.90, 1.00 D), respectively. Conclusions: The ECCP provided with OPD SCAN III could be used as an alternative option for the CHM after specific modifications in eyes with previous myopic SMILE surgery when the preoperative data are unavailable considering the narrowest agreement between the modified ECCP and the CHM. Otherwise, caution must be raised considering the wide LOA. [ABSTRACT FROM AUTHOR]

PURPOSE: The current study was performed to analyze the prevalence and presentation patterns of corneal astigmatism types in cataract surgery candidates. Methods: Preoperative corneal astigmatism were prospectively measured with Autokeratometer in 780 patients (1018 eyes) during the year (2018) in cataract surgery (phacoemulsification) candidates. Descriptive and analytical statistics of astigmatism severity and keratometric data were performed based on age and sex. Results: A total of 1018 eyes of 780 patients were included in the present study, of which 445 (57.1%) were female and 335 (42.9%) were male. Of the 1018 evaluated eyes, 590 (58%) were female and 428 (42%) were male. The mean age of the patients was determined as 65.88 ± I 1.43 years. The mean flat and steep-axis keratometric values were recorded as 44.75 ± 1.86 D and 43.82 ± 1.69 D, respectively. Women showed significantly steeper corneas. Based on LOCS III system, the types of cataracts were as follows: Posterior subcapsular 37.4%, nuclear 28%, cortical 1%, and mixed 33.6%. Types of astigmatism were as follows: 34.7% with-the-rule (WTR), 29.3% against-the-rule (ATR), 35.3% oblique and 0.7% had no astigmatism. A significant relationship of the type of astigmatism with gender and age group was observed (P <0.001), where the prevalence of WTR and ATR were found to be higher among women and men, respectively. The prevalence of WTR was higher among lower age groups, while the prevalence of ATR was found to be higher among older age groups. Furthermore, 70.8% of the eyes revealed astigmatism of at least 0.5 diopters, followed by astigmatism of at least I diopter (33.6%), astigmatism of at least 1.5 diopters (16.2%0, and astigmatism of at least 2 diopters (9.2%). Conclusions: The Findings showed a significant prevalence of astigmatism greater than one diopters in these patients. The results of the study could provide valuable data for cataract surgeons and IOL manufacturers regarding the prevalence and type of corneal stigmatism. [ABSTRACT FROM AUTHOR]

To evaluate the anterior segment biometry characteristics in congenital cataract patients before undergoing surgery in a tertiary eye care centre. We retrospectively reviewed the charts of congenital cataract patients aged less than 15 years who had undergone the congenital cataract surgery from Jan-Dec, 2015. 451 eyes of 351 patients were reviewed. The eyes were examined using an autorefract-keratometer, applanation A-scan and parameters like keratometry, axial length, corneal astigmatism were noted. The mean age at the surgery was 92.4 ± 4.13 months (range 6 months to 15 years). The ratio of boys to girls was 2.34:1. The mean axial length was 21.94 ± 1.94 mm. Girls had shorter axial length than boys (21.53 mm vs 22.11 mm, p = 0.01). The axial length in the cataractous eyes in bilateral cases was significantly smaller than that in the unilateral cases (21.46 mm vs 22.55 mm, p < 0.0001).The mean keratometry was 44.12 ± 2.6 D. Girls had larger mean keratometry value than boys (44.71 vs 43.88, p = 0.0032). Keratometry values were higher in cataractous eyes in bilateral cases than in the unilateral cases (44.61 D vs 43.51 D, p < 0.0001). The mean corneal astigmatism was 1.49 ± 1.13 D. The prevalence of the corneal astigmatism of 2.0 D or more was 25.5%. The with-the-rule astigmatism was the most frequent type (62.53%). Girls had higher mean astigmatism than boys (p = 0.0122). The mean corneal astigmatism was higher in the cataractous eyes in bilateral cases than in the unilateral cases (p = 0.0094). The axial length, mean keratometry and corneal astigmatism in congenital cataract patients varied with age, gender, and laterality. The data on biometry characteristics of Nepalese pediatric patients provided in the present study are of clinical significance and hence greatly enhance the guidelines for treatment decisions, IOL power calculations and management of congenital cataract patients. [ABSTRACT FROM AUTHOR]

Purpose: To determine corneal astigmatism prevalence, its correlations with age and symmetry pattern in fellow eyes of patients undergoing cataract surgery. Methods: This is a clinical-based retrospective cross-sectional study. Keratometry measurements of patients undergoing cataract surgery assigned to University Clinical Center Tuzla, Bosnia and Herzegovina, between January 2011 and June 2012 were recorded and analyzed retrospectively. Results: The study consisted of 4080 eyes of 2205 consecutive cataract surgery patients with a mean age of 68.24 years ± 9.25 (SD) (range 32–84 years), and 54.0% of the patients were women. Mean corneal astigmatism was 0.72 ± 0.61 D (range 0–6.5 D). The prevalence of corneal astigmatism 1.0 D or more was in 1291 eyes (31.64%), 1.5 D or more in 736 eyes (18.03%), 2.0 D or more in 396 eyes (9.71%) and 3.0 D or more in 108 eyes (2.65%). There was no significant difference in the magnitude of astigmatism between age groups (p = 0.10), male and female (p = 0.29) or right and left (p = 0.75) eyes. The prevalence and amount of astigmatism increased with age (p < 0.05). Gradual shift from with-the-rule astigmatism toward against-the-rule astigmatism was observed (p = 0.03). Patients with higher amount of astigmatism in one eye are more likely to have significant astigmatism in fellow eye (p < 0.01). Symmetry in pairs of eyes is present in eyes with astigmatism greater than 2.5 D (p < 0.01). Conclusion: This study provides useful reference data for cataract surgeons and patients from Bosnia and Herzegovina. [ABSTRACT FROM AUTHOR]

Objective: To compare astigmatism induced by the superior and temporal section inmanual small incision cataract surgery. Material and Method: This study was a randomized comparative trial conducted at the department of Ophthalmology, Hayatabad Medical Complex Peshawar, from May 31, 2018 to Nov 30, 2018. 164 patients were included through Out Patient Department and informed written consent was taken. Personal biodata was recorded on predesigned proforma. Patients were randomly allocated by lottery method to superior incision group and temporal incision group. Corneal astigmatism was measured by Helm holtz keratometer (Topcon OM-4). Results: A total of 164 patients of 50-74 years of age of either gender undergoing manual small incision cataract surgery were studied, who were divided into two equal groups. Overall male to female ratio was 1.20:1. Sex distribution among the groups was insignificant with p-value= 0. 376. Surgically induced astigmatism wise distribution shows that patients in superior incision group (Group A) have average astigmatism of 0.328+0.3335SD while in temporal incision group (Group B) it was 0.243+0.296SD, which was significant with p-value = 0.080. Conclusion: Both incisions resulted in same amount of mean astigmatism at 6 weeks and difference in mean surgically induced astigmatism (SIA) was found to be statistically insignificant. Temporal incision had the trend of inducing with-therule astigmatism. [ABSTRACT FROM AUTHOR]

Purpose: To compare the preoperative and postoperative measurements of optical low-coherence reflectometry (OLCR) biometry and assessment of its refractive predictability. Methods: A total of 114 eyes of 102 patients who underwent cataract treatment were prospectively examined. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), K (keratometry) 1, K2, K average (KAVE) and K astigmatic (KAST) values were recorded using Lenstar LS 900 (Haag-Streit, Koeniz, Switzerland) OLCR device. The IOL (intraocular lens) power was measured based on the SRK/T formula. The cases were divided into three subgroups according to AL (Group 1: AL < 22 mm, Group 2: 22 mm ≤ AL < 24 mm, Group 3: 24 mm ≤ AL). The mean absolute error (MAE) calculated for each eye. Results: The right eyes of 45 patients (44.1%), left eyes of 45 patients (44.1%), and both eyes of 12 patients (11.7%) were examined. The average AL in the preoperative period was 23.19 ± 1.01; it was 23.20 ± 0.99 in the postoperative period (p > 0.05). A significant deepening was detected in the postoperative ACD (preop 2.76 ± 0.38 mm, postop 3.81 ± 0.46 mm, p < 0.001). CCT was measured as 521.4 ± 36.3 µm in the preoperative period and as 530.8 ± 42.8 (p > 0.05) µm in the postoperative period. The average mean absolute error (MAE) was measured as 0.48 ± 0.41 D, whereas refractive error was − 0.081 ± 0.67 D. The MAE distribution of cases was found to be ≤ 1.5 D 109 (95.6%) eyes, and ≤ 2.0 D in 114 (100%) eyes. MAE values according to AL of the cases were calculated as 0.71 ± 0.83 D in group 1, 0.49 ± 0.43 D in group 2 and 0.41 ± 0.36 D in group 3 (p > 0.05). Conclusion: When the measurement and refractive results of the OLCR biometry were evaluated, it was observed that there was a very satisfactory result and a predictable device compatible with the current literature. The SRK/T formula, one of the new generation formulas, has shown high MAE and RE results in eyes with AL ≤ 22 mm, although not statistically significant. Other new generation formulas should be tried in these eyes. [ABSTRACT FROM AUTHOR]

Purpose: To compare measurements of axial length (AL), corneal curvature (K), anterior chamber depth (ACD) and white-to-white (WTW) distance on a new device combining Scheimpflug camera and partial coherence interferometry (Pentacam AXL) with a reference optical biometer (IOL Master 500). To evaluate differences between IOL power calculations based on the two biometers. Methods: Ninety-seven eyes of 97 consecutive cataract or refractive lens exchange patients were examined preoperatively on IOL Master 500 and Pentacam AXL units. Comparisons between two devices were performed for AL, K, ACD and WTW. Intraocular lens (IOL) power targeting emmetropia was calculated with SRK/T and Haigis formulas on both devices and compared. Results: There were statistically significant differences between two devices for all measured parameters (P < 0.05), except ACD (P = 0.36). Corneal curvature measured with Pentacam AXL was significantly flatter then with IOL Master. The mean difference in AL was clinically insignificant (0.01 mm; 95% LoA 0.16 mm). Pentacam AXL yielded higher IOL power in 75% of eyes for Haigis formula and in 62% of eyes for SRK/T formula, with a mean difference within ± 0.5 D for 72 and 86% of eyes, respectively. Conclusions: There were statistically significant differences between AL, K and WTW measurements obtained with the compared biometers. Flatter corneal curvature measurements on Pentacam AXL necessitate formulas optimisation for Pentacam AXL. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the intraobserver repeatability of central corneal thickness, peripheral corneal thickness (PCT), keratometry values (steep K, flat K), white-to-white diameter, and anterior chamber depth using the Sirius topography device (Costruzione Strumenti Oftalmici, Florence, Italy) in healthy eyes. Methods: A Sirius device was used by a single examiner to assess 100 eyes in 50 healthy patients. Two consecutive scans were acquired for each eye. Repeatability was assessed using test-retest variability, the coefficient of variation (COV), and the intraclass correlation coefficient (ICC). Results: Fifty patients (100 eyes) met the inclusion criteria. There were 18 women (36%) and 32 men (64%), with an age range of 23 to 56 years. The mean age was 30.38±8.03 years. A COV of 0.4% or less and an ICC of more than 0.99 (showing excellent repeatability) were achieved for most parameters, with the exception of PCT (at 2.5-mm temporal, superior, inferior, and nasal thickness). Conclusion: The anterior segment parameters obtained using the Sirius Scheimpflug camera-Placido corneal topography system were highly repeatable. [ABSTRACT FROM AUTHOR]

Purpose: To explore the relationship between intraocular pressure (IOP) measurements and topographical variations in corneal curvature and corneal thickness in a cohort of keratoconic patients presenting to a newly-established regional Keratoconic diagnostic and monitoring clinic in Northern Ireland.Methods: IOP was recorded, using a hand held ICARE tonometer, at central, nasal and temporal locations on keratoconic corneae of 27 consecutive patients attending clinic. Pachymetry and sagittal keratometry were recorded in matched locations using the Pentacam Topographer. Eyes with history of corneal surgery or anterior surface pathology were excluded.Results: The median (interquartile range) central keratometry, pachymetry (CCT) and IOP measurements for 49 eyes were 44.1D (42.2D-48.1D); 495 μm (460 μm-526 μm); 10 mmHg (8 mmHg-13 mmHg) respectively. Temporal and nasal keratometry, pachymetry, and IOP values, recorded on midline, were temporal 41.9D (40.7D-42.8D); 621 μm (579 μm-650 μm); 14 mmHg (11 mmHg-16 mmHg); nasal 40.8D (39.5D-42.5D); 641 μm (599 μm-698 μm); 13 mmHg (12 mmHg-17 mmHg). A moderate correlation was shown between reduction in CCT and increase in mean central keratometry (Spearman's Coefficient (ρ) -0.72 P = 0.00). A moderate correlation was found between reduction in CCT and reduction in IOP, as recorded centrally (ρ = 0.37 P = 0.01). Mid-peripheral values demonstrated similar trends in the relationship between keratometry and IOP (nasal ρ = -0.47 P = 0.00; temporal ρ = -0.38 P = 0.00) and pachymetry and IOP (nasal ρ = 0.29 P = 0.05; temporal ρ = 0.33 p = 0.02).Conclusion: In this pilot study, a positive correlation exists between pachymetry, keratometry and IOP. Topographically variations in intraocular pressure mimic changes in keratometry and pachymetry. [ABSTRACT FROM AUTHOR]

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The aim of this paper is to describe prevalence and correlation of Keratometry, Axial Length and Post Operative IOL Power measures in cataract surgery for different age group population. Prospective and Interventional Randomized study concluding Sample size of 200. Kaverage readings, Axial Length readings and IOL power calculation are taken by Optical Coherence Biometry (AL-Scan). The observation made on different age groups and different parameters groups. 200 eyes observed among them 105 are male and 95 are females, ranging in between 40 to 70 years with the male: female ratio of 1: 0.90. The mean ± st.dev of age is 61.97 ± 8.57. The mean ± st.dev of Keratometry is 44.57±1.59. The A.L. observed for the inclusion criteria of 21-25 m.m. in accordance to the Optical Coherence Biometry, the Mean ± St dev is 23.16 ± 0.78. The IOL Power observed for same sample size with the Mean ± St dev of 20.88 ± 1.59. The maximum frequencies of cases are in 61-70 years of age group among them 59 cases are of NS with PSC. The most affected type of cataract is Nuclear Sclerosis with Posterior Sub Capsular cataract having total count of 88 (44.00%) in our study. The maximum frequencies of Keratometric reading is 185 (46.25%) among five groups, in the group range of 44.01D- 46 D. The maximum frequencies for axial length are 79 (39.50%), in the group range of 22.01-23.00 mm among four groups. The IOL Power groups sub divided into six groups, the group 20.50 to 22.00 D showing maximum frequencies of 96 (48.00%). The prevalence for Keratometry is 44.57 D; for axial length 22.63mm; for IOL Power is 21.23 D and for cataract, 61-70 year of age, males are prone to nuclear and PSC type of cataract. Correlation between IOL Power to AL reading shows linear inverse relation but AL and IOL Power with K reading does not show linear relation. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to assess the repeatability and agreement of five imaging devices, namely, the Pentacam (Oculus), Sirius (CSO), Orbscan IIz (Bausch and Lomb), Corvis (Oculus), and ultrasound pachymetry (UP, Tomey) in measuring steep keratometry (sKm), flat keratometry (fKm), central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior chamber depth (ACD) in healthy individuals. Design: This was prospective, comparative study. Subjects: Forty-six healthy Indian patients. Materials and Methods: Forty-six eyes of 46 healthy participants underwent three consecutive scans on each device by a single examiner. Within-subject standard deviation, test–retest repeatability (TRT), and coefficient of variation (COV) for assessing repeatability and Bland–Altman plots for the agreement between the mean measurements of each machine were analyzed. Main Outcome Measures: The repeatability and agreement between the five devices for the measurements of sKm, fKm, CCT, TCT, and ACD. Results: The TRT of sKm measurements ranged between 0.23 diopter (D) (with Pentacam) and 0.83 D (with Orbscan). The same of fKm, TCT, ACD, and CCT measurements ranged between 0.28 D (with Pentacam) and 0.74 D (with Sirius), 7.78 μm (Sirius) and 19.81 μm (Orbscan), 0.05 mm (Orbscan) and 0.07 (Sirius), and 7.36 μm (Sirius) and 18.02 μm (Orbscan), respectively. The TRT of sKm and fKm measurements with Pentacam was significantly lower than those with Orbscan and Sirius. The TRT of TCT measurement with Sirius was significantly lower than that with Pentacam (4.53 μm) and Orbscan (7.15 μm). There were statistically significant differences in the mean measurements of all parameters between the devices. The 95% limit of agreement on the Bland–Altman analysis was wide for the measurement pairs with all the devices. Significant proportional bias in the agreement was detected for TCT measurements with all the device pairs and for the ACD measurements between Sirius and Pentacam. Conclusions: The repeatability estimates of sKm, fKm, TCT, ACD, and CCT measurements with Pentacam, Orbscan, Sirius, Corvis, and UP in Indian eyes were good. However, the differences in the measurements between the devices were statistically significant and the same cannot be used interchangeably for anterior segments measurements.

Purpose: This study aimed to evaluate the theoretical influence on intraocular lens power (PIOL) calculation of the use of keratometric approach for corneal power (Pc) calculation in keratoconus and to develop and validate an algorithm preliminarily to minimize this influence. Methods: Pcwas calculated theoretically with the classical keratometric approach, the Gaussian equation, and the keratometric approach using a variable keratometric index (nkadj) dependent on r1c(Pkadj). Differences in PIOLcalculations (ΔPIOL) using keratometric and Gaussian Pcvalues were evaluated. Preliminary clinical validation of a PIOLalgorithm using Pkadjwas performed in 13 keratoconus eyes. Results: PIOLunderestimation was present if Pcwas overestimated, and vice versa. Theoretical PIOLoverestimation up to −5.6 D and −6.2 D using Le Grand and Gullstrand eye models was found for a keratometric index of 1.3375. If nkadjwas used, maximal Δ PIOLwas ±1.1 D, with most of the values ≤±0.6 D. Clinically, PIOLunder- and over-estimations ranged from −1.1 to − 0.4 D. No statistically significant differences were found between PIOLobtained with Pkadjand Gaussian equation (P > 0.05). Conclusion: The use of the keratometric Pcfor PIOLcalculations in keratoconus can lead to significant errors that may be minimized using a Pkadjapproach.

Kjell G Gundersen,1 Richard Potvin21IFocus Øyeklinikk AS, Haugesund, Norway; 2Science in Vision, Akron, NY, USAPurpose: To prospectively evaluate postoperative clinical outcomes with implantation of toric intraocular lenses (IOLs) using preoperative keratometry from an optical low coherence reflectometry (OLCR) ocular biometer (Lenstar® LS900) and the built-in Barrett toric calculator.Patients and methods: A prospective observational study recruited one or both eyes of subjects who underwent uncomplicated cataract surgery with toric IOL implantation using OLCR biometery data and the Barrett toric IOL calculator for toric IOL planning. Data were collected at the preoperative, operative, 1-day and 2-month postoperative visits. The primary outcome measure was the manifest refractive astigmatism magnitude at 2 months. The secondary outcome measures included the manifest refraction, corneal keratometry, and distance visual acuity (corrected and uncorrected). The results obtained with the Barrett toric calculator were compared with simulated results based on the toric calculators designed for the IOLs being used.Results: Data from 98 eyes of 54 subjects were available for analysis. In the 74 eyes with postoperative lens orientation as planned, and sufficient IOL cylinder power to correct subjects’ measured astigmatism, 77% of eyes (57/74) had 0.5 diopter (D) or less refractive cylinder 2 months postoperatively, while 89% (66/74) had 0.75 D or less. Simulated results after adjusting actual IOL orientation to the planned orientation suggested that the Barrett calculator would result in postoperative residual astigmatism about 0.2 D lower than that expected with standard calculators.Conclusion: Use of the Barrett toric calculator with biometry data from the Lenstar LS900 biometer for toric IOL planning in a clinical setting resulted in significantly lower levels of residual refractive cylinder than might be expected with standard calculators. Postoperative lens orientation and variability in the measurement of corneal astigmatism pre- and postoperatively appear to be important limiting factors in toric IOL outcomes.Keywords: Lenstar, keratometry, cataract surgery, astigmatism, cylinder, toric IOL

Tiago B Ferreira, Filomena J Ribeiro Department of Ophthalmology, Hospital da Luz, Lisbon, Portugal Purpose: To assess the accuracy of corneal astigmatism evaluation measured by four techniques, Orbscan IIz®, Lenstar LS900®, Cassini®, and Total Cassini (anterior + posterior surface), in pseudophakic eyes. Patients and methods: A total of 30 patients (46 eyes) who had undergone cataract surgery with the implantation of a monofocal intraocular lens (AcrySof IQ) were assessed after surgery. For each eye, subjective assessment of astigmatism and its axis was performed. Minimum, maximum, and mean keratometry and astigmatism and its axis were evaluated using the four measurement techniques. All measurements were compared with the subjective measurements. Agreement between each measurement technique and subjective assessment was evaluated using Bland–Altman plots. Linear regressions were performed and compared. Results: Linear regression analysis of astigmatism axis showed very high R2 for all models, with Total Cassini showing the least difference to the unit slope (0.052) and the least difference to a null constant (3.790), although not statistically different from the other models. Regarding astigmatism value, the Cassini and Total Cassini models were similar and statistically better than the Lenstar model. Cassini and Total Cassini showed better J0 compared with Orbscan. Conclusion: On linear regression models, Cassini and Total Cassini showed the best performance regarding astigmatism value. Cassini and Total Cassini also showed the least J0 deviation from the Cartesian origin compared with Orbscan, which had the lowest performance. Total corneal measurement with the color LED topographer seems to be a better technique for astigmatism assessment. Keywords: astigmatism, keratometry, topography

AIM: To investigate the corneal high order aberrations in adults with myopia and to study its correlations with myopic degree and keratometry. METHODS: A total of 63 patients(126 eyes)from the ophthalmology department of our hospital were included in this study during May 2014 to June 2015. Visual acuity, intraocular pressure(IOP), diopter, slit lamp examination, central corneal thickness(CCT), funduscopic examination, corneal topography and corneal total higher order aberrations(THOAs)were recorded. Right eye was selected. According to the spherical equivalence(SE), 63 eyes were divided into two groups, the mild to moderate myopia group(M-M group, SERESULTS: Z44 was found a statistic difference between the M-M group and H group(t=2.51,P=0.02). IOP was negatively correlated with Z5-3(r=-0.52,P=0.01), and CCT was positively correlated with Z4-4(r=0.43,P=0.03)in H group. There was no correlation between higher order aberrations and SE in M-M group(all P>0.05)Total coma aberration(TCA)was negatively correlated with SE(r=-0.57,P=0.002)and spherical degree(Sph, r=-0.55,P=0.003)in H group. Z40 was positively correlated with average K(AK)(M-M group:r=0.40,P=0.02. H group:r=0.55, P=0.03), K steep(Ks)(M-M group:r=0.39, P=0.02. H group:r=0.51, P=0.01)and K flat(Kf)(M-M group:r=0.40, P=0.02. H group:r=0.57, P=0.01)in both groups. Z53 was negatively correlated with Ks (r=-0.4,P=0.04)in H group. CONCLUSION: The THOAs parameters are influenced by diopter and keratometry. TCA is negatively correlated with SE and Sph in patients with high myopia, and spherical aberration is positively correlated with keratometry.

Purpose: To compare the clinical measurements with the new IOLMaster-700 from those obtained with the Aladdin. Methods: A prospective, cross-sectional, observational Comparative study.24 eyes were assessed using the two devices. Measurements of axial length (AL), anterior chamber depth (ACD), mean keratometri (Km) flattest (Kf), steepest keratometry (Ks) and white-to-white (WTW) were done with both devices in random order. Results: No statistically significant differences (p>0.05) between the two biometers were found for AL (mean difference 0.000 mm), ACD (mean difference 0.164 mm) and Kf (mean difference 0.020 D). In Km (mean difference was 0.085 D), Ks (mean difference 0.151 D) and WTW (mean difference 0.29 mm) the differences was statistical different. Conclusions: Measurements with the new IOLMaster-700 correlated well with those obtained with the Aladdin in patients with clear lens.

Osama Ibrahim,1 Ahmed Elmassry,1 Amr Said,1,2 Moones Abdalla,2 Hazem El Hennawi,1 Ihab Osman1 1Department of Ophthalmology, Alexandria University, Alexandria, Egypt; 2Roayah Vision Correction Center, Alexandria, Egypt Purpose: To assess the safety, predictability, and effectiveness of Keraring intrastromal corneal ring segments (ICRS) insertion assisted by femtosecond laser and corneal collagen cross-linking (CXL) for keratoconus correction. Patients and methods: In this prospective, noncomparative, and interventional case series, 160 eyes of 100 adult keratoconus patients with poor best-corrected visual acuity (BCVA) (less than 0.7) and intolerance to contact lens wear were included. Patients underwent femtosecond laser-assisted placement of ICRS and CXL. All patients were examined for a complete ophthalmological test: uncorrected visual acuity (UCVA), BCVA, spherical equivalent, keratometry (K1-flat and K2-steep), pachymetry, and Scheimpflug imaging with the Pentacam at 1 week and at 1, 3, and 6 months postoperatively. Results: At 6 months, a significant difference was observed (P

AIM:To explore the method to calculate intraocular lens(IOL)power after corneal refractive surgery.METHODS:A retrospective study was conducted. Fourteen patients(23 eyes)with age-related cataract after corneal refractive surgery were treated in our hospital from March 2013 to June 2015. Patients were divided into LASIK group(laser in situ keratomileusis, 9 cases with 15 eyes)and RK group(radial keratotomy, 5 cases with 8 eyes). Corneal curvature values of the lowest point in central 2.5mm were measured by corneal topography, which were used in SRK-T formula. Phacoemulsification with IOL implantation was performed with the target refraction was between -1.0～-1.5D. The patients were followed up for uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA)and refractive statuses at 3mo after the operations. The predictive error of the calculation formula were calculated and compared to Shammas formula and Barrett True K formula from www.iolcalc.org respectively. Statistical analysis of the data was performed using independent-samples t test.RESULTS:The UCVA(LogMAR)of LASIK group and RK group were 0.15±0.11,0.21±0.16 respectively, refractive status were -0.43±1.04,-1.52±1.01D and the predictive errors of the SRK-T were -0.71±0.80,0.43±0.99 at 3mo after operations. There was significant differences(PCONCLUSION:Our results imply that using our observed method, the postoperatively predictive errors are mild myopia, which can be applied for determination of IOL power for cataract patients who received corneal refractive surgery. And it can improve accuracy of the intraocular lens power calculation for cataract patients with corneal myopic refractive surgery, especially for patients with LASIK.

This review article aimed to evaluate ocular biometric changes after trabeculectomy. The PubMed database was searched using the keywords “axial length” (AL), “anterior chamber depth” (ACD), “corneal astigmatism,” “corneal topography” and “trabeculectomy.” The extracted studies were categorized based on the evaluated parameters and the biometry method (contact and non-contact). Comparable studies with respect to their sample size were combined for statistical analysis. Twenty-five studies including 690 individuals which met the inclusion criteria were selected. After trabeculectomy, a significant and persistent AL reduction, with a range of 0.1-0.19 and 0.1-0.9 mm measured with contact and non-contact methods, respectively, was observed. With respect to topographic changes, 0.38-1.4 diopters (D) with-the-rule (WTR) astigmatism was induced postoperatively. All studies revealed ACD reduction immediately after surgery, which gradually deepened and approximated its preoperative levels on day 14. ACD reduction was not significant after that period in the majority of cases. In conclusion, changes in ACD is of small amount and of short period, thus it can be ignored; however, reported changes in AL and keratometry are of sufficient magnitude and can affect the refractive prediction of combined cataract surgery and trabeculectomy.

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 < 0.001, respectively). Comparing subgroups, the large CR and small WTW group had larger angles α (0.49 ± 0.27 vs. 0.41 ± 0.21, p < 0.001; 0.46 ± 0.27 vs. 0.44 ± 0.21, p < 0.05, respectively) and κ (0.29 ± 0.25 vs. 0.24 ± 0.15, p < 0.01; 0.29 ± 0.25 vs. 0.26 ± 0.19, p < 0.05, respectively). The differences in interocular angles α and κ showed correlation with interocular WTW (r = - 0.255, p < 0.001; r = - 0.385, p < 0.001). Eyes with smaller WTW tended to have larger angle κ (0.28 ± 0.27 vs. 0.25 ± 0.15, p < 0.05)., Conclusion: The size of angle α/κ may be correlated to CR and WTW, and a larger WTW eye may suggest a smaller angle κ compared with the fellow eye., (© 2024. The Author(s).)

Purpose: To assess the feasibility and reliability of biometric measurements taken with the Eyestar 900 device in keratoconus eyes in comparison with those taken with the Pentacam HR and IOLMaster 700., Methods: Seventy-five eyes of 75 patients with keratoconus were included. The central corneal thickness (CCT), thinnest point of corneal thickness (TCT), axial length (AL), flat (K1) and steep (K2) anterior and posterior (Kp1, Kp2) keratometry, maximal keratometry (KMax) and anterior chamber depth (ACD) were compared between the Eyestar 900, Pentacam HR and IOLMaster 700. Reliability parameters such as the coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated. Pearson's r was determined to assess the correlation between devices., Results: A high repeatability (CoV < 1%) and intraclass correlation (ICC > 0.9) was found for all devices, led by AL, TCT, K1 and K2 (CoV 0.01-0.36%; ICC 0.994-1.00). The largest correlation between devices was found for AL (Eyestar vs. IOLMaster, r = 1.0), K1 (Eyestar vs. IOLMaster, r = 0.997) and ACD (Eyestar vs. IOLMaster, r = 0.995; Pentacam vs. IOLMaster, r = 0.987; Eyestar vs. Pentacam, r = 0.983), but there were significant differences in measured values between devices (p < 0.001), whereas the correlation was only slightly lower (r = 0.947 to 0.994) for KMax, CCT, TCT, K2, Kp1 and Kp2., Conclusion: Keratometric and axial length measurements with the Eyestar 900 were feasible and revealed a high repeatability and a good correlation to the other devices in eyes with keratoconus., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Several studies have previously reported the normal values of corneal volume (CV) in various populations, whereas little is known about the CV distribution in healthy young Chinese adults. Our study aimed to investigate the distribution of CV and its relationships with other ocular biometric parameters among healthy young Chinese adults., Methods: A total of 1645 eyes from 1645 students at Dali University in Yunnan Province, China, were analyzed. Pentacam was used to measure CV. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated by Corvis-ST. Other biometrical parameters, including axial length (AL), keratometry, and white-to-white (WTW) distance, were measured using IOL Master., Results: The mean age of the study population was 19.01 ± 0.92 years, and 68.81% of them were women. The CV was normally distributed in the whole sample, with a mean value of 61.23 ± 3.22 mm 3 . CV and CCT were significantly smaller in the Yi ethnic group than in the Han ethnic group (p < 0.01). CCT (coefficient: 0.085; p < 0.001) and keratometry (coefficient: 0.422; p < 0.001) were positively correlated with CV, while AL (coefficient: -0.204; p < 0.001), WTW distance (coefficient: -0.236; p < 0.001) and bIOP (coefficient: -0.06; p < 0.001) were inversely associated with CV., Conclusions: Our study provides an age-specific distribution of CV among healthy young Chinese adults. CCT, keratometry, AL, WTW distance and bIOP were important factors associated with CV., (© 2024. The Author(s).)

Purpose: This study aimed to evaluate the effects of dry eye on the reproducibility of keratometry (K) measurements in patients presenting for cataract surgery., Methods: A non-randomized controlled clinical study was performed. Eighty-three eyes of eighty-three patients with cataracts who were enrolled in our hospital from March 2020 to July 2020 were studied. The mean non-invasive tear film break-up time (NIBUT), corneal fluorescein staining score, and ocular surface disease (OSD) SPEED II questionnaire were measured and recorded prior to surgery, and the patients were assigned to a "dry eye" group (n=35) or a "non-dry eye" group (n=48). The K of the patients was measured twice by a Tomey OA-2000 (an average of three times each). The difference of the mean K (ΔKm) and astigmatism vector (ΔK vector ) between the two measurements was calculated. The ΔKm and ΔK vector between the two groups were compared. The relationship between the measurement parameters of dry eyes and the accuracy of the preoperative K values was analyzed., Results: ΔKm was 0.09 D [0.03; 0.19] in the non-dry eye control group and 0.28 D [0.18; 0.50] in the dry eye group, with a statistical difference between the two groups (P=0.005). The ΔK vector of the non-dry eye control group was 0.22 D [0.14; 0.42], and that of the dry eye group was 0.50 D [0.28; 1.06]. There was a significant difference between the two groups (P=0.010). Between the two groups, the percentage of the ΔKm and ΔK vector values greater than 0.5 D were statistically different (P<0.05). There was no significant difference in ΔKm between the groups with NIBUT>5s and NIBUT≤5s (P=0.537). There was no significant difference in ΔKm between groups≥2 and<2 on the OSD SPEED II questionnaire scores (P=0.442)., Conclusion: Dry eye can affect the reliability of keratometry measurements before cataract surgery, thereby affecting the accuracy of intraocular lens power calculations. In cataract surgery planning, it is necessary to detect subjective and objective indicators of dry eye in patients and carry out effective intervention so as to avoid refractive errors caused by inaccurate keratometry measurements., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Purpose: We aimed to compare the accuracy of the intraocular lens (IOL) calculation formula using the standard keratometry (K) and total K (TK) during the femtosecond laser-assisted cataract surgery (FLACS) with a monofocal IOL with enhanced intermediate function using currently used formulas., Methods: A retrospective review of 125 eyes from 125 patients who had undergone FLACS with implantation of monofocal IOL with enhanced intermediate function was conducted. The predicted refractive power was calculated using an optical biometer (IOLmaster 700) according to the K and TK in the Barrett Universal II, SRK/T, Haigis, and Holladay 2 formulas. Absolute prediction error (APE) obtained from the actual postoperative refractive outcomes and the refractive error predicted in each formula was compared one month after surgery., Results: Mean APE ranged between 0.29 and 0.39 diopters (D) regardless of the calculation formula and the method of measuring corneal curvature. Significant differences were observed in the APE from the four formulas and the two keratometric measurements (p = 0.014). In a total of 125 eyes from 125 patients, the mean APE was lowest with the Barrett Universal II formula. Across all formulas, both the mean APE and the median APE tended to be lower for K than for TK, although there was no significant difference. Approximately 70% to 80% of the patients were included within 0.5 D of the refractive error across all formulas. The percentage of eyes within 0.5 D of APE outcomes was not statistically different between the K and TK data when using each formula., Conclusions: Keratometric measurements considering the poster corneal curvature did not show any additional advantages when implanting the monofocal IOL with enhanced intermediate function during the FLACS.

Purpose: To evaluate the effect of vectored thermal pulsation therapy (VTPT) on the repeatability of biometry readings of two different optical biometers in patients with meibomian gland dysfunction (MGD)., Methods: Patients affected by MGD were included in this prospective, randomized, controlled, investigator-masked study. One eye was randomized to VTPT (LipiFlow®, Johnson & Johnson), and the contralateral eye served as a control. Three visits were scheduled at baseline, 2 weeks and 3 months after the treatment. The main outcome parameter of the study was the repeatability of three calculations of emmetropic intraocular lens power (EIOLP) at the 3 months visit as compared to baseline using an optical biometer (IOLMaster® 700, Carl Zeiss Meditec AG). Repeatability of different keratometry values obtained by the optical biometer and a Placido-disc topographer (MS-39®, CSO) served as secondary outcome parameters., Results: Twenty-nine patients were included in the final analysis. While tear film parameters improved in the study eyes, there were no significant differences regarding the repeatability of three EIOLP measurements between baseline and 3-months-visit in both eyes (p > 0.05) and keratometry measurements in both the optical biometer and the Placido-disc topographer. Remarkably, throughout all study visits, there were some outliers regarding the repeatability of measurements., Conclusion: While both devices showed high repeatability regarding EIOLP and keratometry, future studies are needed to detect high-risk patients for poor repeatability., (© 2023 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

This study aims to compare changes of corneal topography (Galilei G4) before and after the instillation of artificial tears in patients with dry eye disease (DED). Corneal topography was performed in patients 1 min before and after artificial tear instillation. Two types of artificial tears were used: 1% polysorbate 80 (PSB) and 0.5% carboxymethylcellulose (CMC). Of 135 patients, PSB and CMC were instilled in 101 and 34 eyes, respectively. The average value of Sim K increased significantly after instillation (44.07 ± 2.26 diopter (D)) compared to before (43.90 ± 2.02 D, p = 0.006) the instillation of artificial tears. Mean Sim K astigmatism was statistically increased after PSB instillation (1.48 ± 2.17 D) compared to before instillation (1.31 ± 2.10 D, p = 0.049). An axis change of astigmatism 10° or more after artificial tear instillation was found in 51.9% of patients, and 30° or more in 20.0% of patients. Increased Sim K value and significant changes in the astigmatic axis in the corneal topography were observed after instillation of artificial tears in DED patients. PSB instillation had a greater effect on corneal keratometry values than CMC instillation.

Marfan syndrome (MS) is an orphan hereditary connective tissue disease associated with a mutation in the FBN1 gene, which pathological manifestations are characterized by polysystemic involvement. The fibrillin-1 protein is an integral component of the sclera and cornea of the eye, and in MS its structure is distrubed., Purpose: This study assesses potential structural and functional changes in the cornea and sclera of a patient with MS., Material and Methods: Two groups were formed, comparable in the axial length of the eye and age: the main group - 19 patients (38 eyes) with a verified diagnosis of MS, and the control group - 24 patients (48 eyes) with myopia of varying degrees. The results obtained from MS patients were analyzed depending on the absence or presence of ectopia lentis. In addition to measuring the basic ophthalmological parameters (refraction, axial length, visual acuity), topographic keratometry, anterior segment optical coherence tomography, and ocular response analyzer were used for structural and functional assessment of the cornea and sclera., Results: In MS there was a statistically significant increase in the radius of curvature and a decrease in corneal refraction in the central zone compared to the control group. There were no significant differences in central corneal thickness, but there was a significant decrease in the thickness of the sclera in the limbal zone compared to the control group. There were no statistically significant changes in corneal hysteresis and corneal resistance factor in MS., Conclusion: This study confirmed the previously obtained data on the tendency of the optical power to reliably decrease in MS (flattening of the cornea). This symptom can be considered as a compensatory factor affecting clinical refraction, while the decrease in the thickness of the sclera - as the main reason for aaxial length elongation in MS. There were no clear patterns of dependence of the changes in the cornea and sclera analyzed in this study on the presence or absence of ectopia lentis. Changes in the lens, perhaps, should be regarded only as one of the potential components of the ocular symptom complex in MS.