Difference In Corneal Astigmatism Research Articles

Correlation of posterior segment lesions with anterior segment biometric parameters and FBN1 genotype in patients with Marfan syndrome

Objective: To investigate the characteristics of posterior segment lesions in Marfan syndrome (MFS) patients and their relationship with anterior segment biometric parameters and FBN1 genotype. Methods: A cross-sectional study was conducted. A total of 121 MFS patients, 76 males and 45 females, with an average age of (11.72±11.66) years, who visited the Department of Ophthalmology, Eye & ENT Hospital of Fudan University from January 2013 to March 2023 were included. The presence of posterior scleral staphyloma was observed using B-mode ultrasound, and macular lesions were identified and classified using the atrophy-traction-neovascularization system based on ultra-widefield fundus images, color fundus images, and optical coherence tomography scans. Anterior segment biometric parameters, including axial length of the eye, average corneal curvature, corneal astigmatism, horizontal corneal diameter, anterior chamber depth, and lens thickness, were collected, and the direction and extent of lens dislocation were observed. Molecular genetic analysis of FBN1 gene mutations in patients was performed using next-generation sequencing based on a panel of ocular genetic diseases, and the impact of the genotype and anterior segment biometric parameters on the posterior segment manifestations was analyzed. Results: Sixty patients exhibited posterior segment lesions, including retinal detachment (4 cases, 3.31%), macular lesions (47 cases, 38.84%), and posterior scleral staphyloma (54 cases, 44.63%). There was statistically significant difference in axial length of the eye between patients with and without posterior scleral staphyloma [23.09 (22.24, 24.43) and 27.04 (25.44, 28.88) mm], between patients with and without macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.78) mm], and between patients with and without atrophic macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.79) mm] (all P<0.001). There was statistically significant difference in anterior chamber depth between patients with and without macular lesions [3.11 (2.75, 3.30) and 3.34 (3.09, 3.60) mm] (P<0.05). There was also statistically significant difference in corneal astigmatism between patients with and without posterior scleral staphyloma [2.15 (1.20, 2.93) and 1.40 (1.00, 2.20) diopters] (P<0.05). The location and region of the FBN1 gene mutation not only showed statistically significant difference from the positive rates of posterior scleral staphyloma and macular lesions (all P<0.05), but also influenced the occurrence of atrophic macular lesions (both P<0.05). Patients with FBN1 mutations located in the transforming growth factor β regulatory sequence had the highest proportion of posterior scleral staphyloma and macular lesions (both 10/11). Conclusions: Posterior scleral staphyloma and macular lesions have a relatively high incidence in MFS patients and tend to progress to more severe grades. The age, axial length of the eye, anterior chamber depth, corneal astigmatism, and location and region of the FBN1 gene mutation are factors affecting the posterior segment lesions in MFS patients.

Significant Changes of Corneal Astigmatism After Levator Muscle Surgery for Acquired Blepharoptosis.

To investigate the change of corneal astigmatism after the correction of blepharoptosis. This was a single-center retrospective cohort study conducted in Taiwan from 2017 to 2021. The medical records of patients with acquired blepharoptosis who had received levator muscle surgeries were collected. The differences in corneal astigmatism between the measurements before and at least 1 month after surgeries were investigated. Subgroup analysis of various severities of blepharoptosis and different types of corneal astigmatism was performed to determine their impacts on the axial changes after blepharoptosis surgeries. A total of 120 eyes of 68 patients were enrolled in this study. The mean axial change of corneal astigmatism was 17.4° after blepharoptosis surgeries, and 55 eyes (45.8%) had a change of at least 10°. In the subgroup analysis, the eyes with against-the-rule, with-the-rule, and oblique astigmatism had 42.9%, 68.4%, and 91.7% with an axial change of at least 10° after surgeries, respectively. The averaged axial change of corneal astigmatism after surgeries was 22.7° in eyes with severe blepharoptosis (margin to reflex distance1 < 1 mm), whereas it was 12.0° in eyes with mild-to-moderate blepharoptosis (margin to reflex distance1 ≥ 1 mm). A high proportion of eyes had a crucial axial change in corneal astigmatism after blepharoptosis surgeries, especially in those with oblique astigmatism and severe blepharoptosis. For blepharoptosis patients needing refractive surgeries or astigmatism correction with toric intraocular lens implantation, a surgical correction of blepharoptosis may be considered beforehand.

Evaluation of a new portable corneal topography system for self-measurement using smartphones: a pilot study.

Herein, we propose the use of the "KeraVio Ring", which is a portable, selfie-based, smartphone-attached corneal topography system that is based on the Placido ring videokeratoscope. The goal of this study was to evaluate and compare corneal parameters between KeraVio Ring and conventional corneal tomography images. We designed the KeraVio Ring as a device comprising 3D-printed LED rings for generating Placido rings that can be attached to a smartphone. Two LED rings are attached to a cone-shaped device, and both corneas are illuminated. Selfies were taken using the KeraVio Ring attached to the smartphone without assistance from any of the examiners. Captured Placido rings on the cornea were analysed by intelligent software to calculate corneal parameters. Patients with normal, keratoconus, or LASIK-treated eyes were included. Anterior segment optical coherence tomography (AS-OCT) was also performed for each subject. We found highly significant correlations between the steepest and flattest keratometry, corneal astigmatism, and vector components obtained with the KeraVio Ring and AS-OCT. In subjects with normal, keratoconus, and LASIK-treated eyes, the mean difference in corneal astigmatism between the two devices was -0.8 ± 1.4 diopters (D) (95% limits of agreement (LoA), -3.6 to 2.0), -1.8 ± 3.7 D (95% LoA, -9.1 to 5.5), and -1.5 ± 1.3 D (95% LoA, -4.0 to 1.1), respectively. The experimental results showed that the corneal parameters obtained by the KeraVio Ring were correlated with those obtained with AS-OCT. The KeraVio Ring has the potential to address an unmet need by providing a tool for portable selfie-based corneal topography.

Long-term results of late “in-the-bag” IOL dislocation surgery

BACKGROUND: Intraocular lens (IOL) repositioning and IOL exchange are the main methods of surgical treatment of late in-the-bag IOL dislocation.&#x0D; AIM: To evaluate refraction, induced corneal astigmatism and IOL tilt after surgical treatment of late in-the-bag IOL dislocation by transscleral suture fixation and exchange to iris-claw IOL with retropupillary fixation.&#x0D; MATERIALS AND METHODS: 78 of patients with late in-the-bag IOL dislocation were included. Transscleral suture IOL fixation was performed in group I (38 eyes), exchange to iris-claw IOL was performed in group II (40 eyes). Refractometry, keratotopography and optical coherence tomography of anterior segment were performed before surgery, 1 week, 1, 3 and 6 months after surgery.&#x0D; RESULTS: The groups did not differ in subjective and objective refraction. But there was significant variability of data in the group I 3 and 6 months after surgery. There was no difference in corneal astigmatism in both groups during 3 months, but a significant increase was found in group II 6 months after surgery. There was no difference in IOL tilt between groups before surgery. Decrease of IOL tilt in 180 degrees plane was observed after 1 month in group II, while there was no difference in 90 degrees plane between groups.&#x0D; CONCLUSIONS: Both methods of late in-the-bag IOL dislocation treatment allow to receive good refractive result, but refraction is less predictable after trans-scleral suture IOL fixation. Surgically induced astigmatism is higher in IOL exchange group due to large sclerocorneal tunnel incision. Transscleral suture IOL fixation does not cause clinically significant IOL tilt.

Comparison of astigmatism between glued and sutured scleral-fixated intraocular lens

Background Posterior chamber intraocular lens implantation in the bag is the preferred mode of correcting aphakia. But, in certain circumstances, this is not possible, thereby requiring modalities of secondary fixation of intraocular lens (IOL).Purpose The aim of this study was to compare the postoperative astigmatism till six months after surgery between the sutured scleral-fixated IOL and the glued scleral-fixated IOL.Patients and methods This is a single-center, prospective, observational, open-label study comparing the postoperative outcome (till 6 months), including astigmatism and best-corrected visual acuity (BCVA), of sutured scleral-fixated intraocular lens (SFIOL) (Group 1) and glued SFIOL (Group 2). There were 25 patients in each group. Patients were followed up on day 1, first week, first, second, third, and sixth month postoperatively. During each postoperative visit, slit-lamp biomicroscopy was performed to evaluate the status of the cornea, anterior chamber, IOL, and position of haptics. Uncorrected visual acuity, BCVA, refraction, and keratometry values (corneal astigmatism) were noted. Cylindrical refraction denoted total astigmatism. The IOL astigmatism was derived by subtracting the corneal astigmatism from the total astigmatism.Results The difference in corneal astigmatism between the two groups was statistically significant at 1, 3, and 6 months postoperatively (P=0.004, 0.002, and 0.012, respectively). The final values at 6 months were 3.00±1.68 diopters (D) in the sutured SFIOL group and 2.08±0.56 D in the glued SFIOL group. The glued SFIOL group required less cylindrical correction till 6 months of follow-up. The BCVA, 6 months postoperatively, was 0.36±0.19 in Group 1 compared with 0.32±0.17 in Group 2, with no statistically significant difference (P=0.404).Conclusion Both techniques proved to be good options for the implantation of SFIOL, but glued SFIOL was better as it led to less astigmatism and hence the need for less spectacle correction.

Posterior and total corneal astigmatism measured with optical coherence tomography-based biometer and dual Scheimpflug analyzer.

To compare corneal astigmatism obtained from an optical coherence tomography-based biometer (OCT) and dual Scheimpflug analyzer (DSA). Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Retrospective case series. Consecutive cases with both OCT and DSA measurements were reviewed. Three parameters were analyzed with OCT and DSA: (1) standard keratometric astigmatism (K vs simulated keratometry [SimK]), (2) posterior corneal astigmatism, and (3) total corneal astigmatism (total keratometry [TK] vs total corneal power [TCP]). The magnitudes of corneal astigmatism obtained from the 2 devices were compared. Vector analysis was used to assess differences in corneal astigmatism between devices. In this study 530 corneas in 530 patients were measured. Compared with the DSA, the OCT produced a lower mean magnitude of posterior corneal astigmatism (-0.19 vs -0.29 diopter [D]) and a higher percentage of eyes with magnitude ≤0.25 D (75.5% vs 41.9%) (P < .05). Comparing TK and TCP, (1) TK was greater in magnitudes (1.03 vs 0.98 D); (2) 84.3% of eyes had differences in magnitude of ≤0.50 D; (3) in eyes with TK astigmatism ≥0.5 D, 34.5% and 60.1% of eyes had differences in steep meridian of ≤5 degrees and ≤10 degrees, respectively, and (4) 59.2% of eyes had vector differences of ≤0.50 D. In with-the-rule and against-the-rule eyes, respectively, the vector differences between TK and TCP were 0.16 D @ 83 degrees and 0.17 D @ 12 degrees, and in posterior corneal astigmatism, 0.06 D @ 173 degrees; and 0.15 D @ 175 degrees. There were clinically significant differences in total corneal astigmatism obtained from OCT and DSA devices. Compared with DSA, OCT produced lower values for posterior corneal astigmatism.

Regional comparison of preoperative biometry for cataract surgery between two domestic institutions.

Regional variations of the preoperative biometry can affect the refractive accuracy of cataract surgery. We aimed to compare the preoperative biometric data for cataract surgery between two domestic institutions. We retrospectively reviewed the preoperative biometric data of 673 consecutive eyes undergoing standard cataract surgery at Miyata Eye Hospital (Miyazaki; M group) and Kitasato University Hospital (Kanagawa; K group), and compared these data between the two groups. We found significant differences in the mean keratometric readings (44.39 ± 1.56D vs. 44.09 ± 1.74D) (unpaired t test, p = 0.034), the anterior chamber depth (3.14 ± 0.43mm vs. 3.46 ± 0.62mm) (p < 0.001), the axial length (23.98 ± 1.62mm vs. 24.59 ± 1.82mm) (p < 0.001), and the lens thickness (4.64 ± 0.48mm vs. 4.37 ± 0.62mm) (p < 0.001), in the M and K groups, respectively. Otherwise, we found no significant differences in corneal astigmatism (p = 0.104), or central corneal thickness (p = 0.480) between the two groups. For subgroup analysis, the prediction error (0.06 ± 0.47D) in the M group was significantly more hyperopic than that (- 0.09 ± 0.54D) in the K group (p = 0.006). There were significant differences in the mean keratometric readings, the anterior chamber depth, the axial length, and the lens thickness, by approximately 0.3D, 0.3mm, 0.6mm, and 0.3mm, respectively. Regional variations of the preoperative biometry did exist to some extent, and were not clinically negligible, in consideration of the precise IOL power calculation and the subsequent refractive accuracy of cataract surgery. University Hospital Medical Information Network Clinical Trial Registry (000037994).

Astigmatic change after pterygium excision with autologous limbal conjunctival graft

Background: Pterygium induces a significant amount of astigmatism. Pterygium excision with conjunctival limbal autograft results in significant reduction in astigmatism by inducing a reversal of pterygium induced corneal flattening thereby improving the vision.&#x0D; Objectives: The aim of this study was to investigate the amount of corneal astigmatism in patients with pterygium before and one month (4 weeks) after surgery. &#x0D; Methodology: The prospective observational study was conducted in 31 patients who underwent pterygium excision with limbal autograft in Kathmandu Medical College Teaching Hospital during the study period of 12 months duration. Patients with recurrent pterygium, pseudopterygium, history of ocular trauma, history of ocular surgery, corneal scarring were excluded from the study. After surgery, patients were followed for four weeks. Findings were recorded in the proforma and statistical analysis was done in SPSS version 19. &#x0D; Results: Pterygium was seen in all age groups with majority being in the active age range of 41-50 yrs. Females were most commonly affected. Significant difference in corneal astigmatism was noted postoperatively with a p value being 0.01.&#x0D; Conclusion: The technique of pterygium excision with limbal conjunctival autograft not only reduces the chances of recurrence but also helps in reducing the induced corneal astigmatism which is responsible for decreased vision in patients with pterygium.

Gender-differences in age-related changes of corneal astigmatism in Korean cataract patients

BackgroundThis cross-sectional study investigated age-related changes in anterior, posterior, and total corneal astigmatism and evaluated sex differences in corneal astigmatism with increasing age in cataract patients.MethodsThis study evaluated eyes with cataracts from May 2009 and July 2013. All eyes underwent a complete ophthalmological examination and corneal Scheimpflug imaging by a Pentacam camera (Oculus, Wetzlar, Germany). Anterior, posterior, and total corneal astigmatism were determined. Power vector J0 and linear regression analyses were determined and compared with respect to age and sex.ResultsFour hundred and fifteen patients (217 men, 198 women) aged 20–89 years were evaluated. For anterior corneal astigmatism, 100% of patients who were 20–39 years old had with-the-rule (WTR) in both sexes. WTR was significantly lower in patients 80–89 years old (25.6% of men and 37.8% of women). For total corneal astigmatism, WTR also tended to decrease with increasing age: 93.3% of men and 100% of women 20–39 years old versus 20.9% of men and 31.1% of women 80–89 years old. The regression coefficient of both the anterior corneal and total corneal J0 vector values analyzed by age were − 0.018 in men and − 0.016 in women (both p < .001).ConclusionsThe against-the-rule shift was faster for total corneal astigmatism than for anterior corneal astigmatism and it occurred earlier in men than in women.Trial registrationRetrospectively registered. Registration number: KC15RISI0241. Registered April 20, 2016.

Femtosecond laser–assisted cataract surgery versus conventional phacoemulsification: Refractive and aberrometric outcomes with a diffractive multifocal intraocular lens

To compare the outcomes of conventional phacoemulsification and femtosecond laser-assisted cataract surgery followed by multifocal intraocular lens (IOL) implantation. Asan Medical Center, Seoul, South Korea. Retrospective case series. Depending on their preference, patients had femtosecond laser-assisted cataract surgery or conventional phacoemulsification. Patients in the femtosecond group with corneal astigmatism greater than 0.75 diopter also had arcuate keratotomy. All eyes had multifocal IOL implantation. One month after treatment, the uncorrected distance and near visual acuities, spherical equivalent, corneal and refractive astigmatism, aberrometry results, and questionnaire results were compared between groups. Correlations between target-induced astigmatism (TIA) and surgically induced astigmatism (SIA) were also compared between the groups. The femtosecond group comprised 17 patients (23 eyes), with arcuate keratotomy performed in 14 eyes. The conventional phacoemulsification group comprised 22 patients(26 eyes). In the femtosecond group, the difference in corneal astigmatism between preoperatively and postoperatively was statistically significant. The correlation between TIA and SIA was greater in the femtosecond group. Corneal root-mean-square higher-order aberrations (RMS HOAs) (P<.01) and total trefoil (P=.043) were significantly higherin the femtosecond laser group. However, internal totalRMS (P=.05), tilt (P=.041), and RMS HOAs (P=.047) were significantly lower in the femtosecond group.Satisfaction scores were significantly higher in the femtosecond group. Astigmatic change was more predictable in the femtosecond laser-assisted cataract surgery group. Internal aberrations, including total RMS, tilt, and RMS HOAs, were lower in the femtosecond group, and patients in that group were more satisfied.

Sex-related differences in corneal astigmatism and shape with age

To compare corneal astigmatism and shape between male and female eyes in relationship to age. Hayashi Eye Hospital, Fukuoka, Japan. Prospective case series. Eyes of men and women in 5 age groups (40 to 49years, 50 to 59years, 60 to 69years, 70 to 79years, and ≥80years) had videokeratographic evaluations using a Placido-Scheimpflug system. Corneal astigmatism decomposed to vertical-horizontal (J0) and oblique (J45) astigmatism components was compared between male and female eyes, and corneal shape changes were compared using videokeratography maps. The study comprised 1000 eyes (100 eyes of male patients and 100 eyes of female patients in each of the 5 age groups). The mean J0 of the total and anterior cornea were significantly smaller in male eyes than in female eyes in all age groups (P≤.0269) with no significant difference in the J45 between sexes, indicating greater against-the-rule (ATR) astigmatism in male eyes. The mean J0 of the posterior cornea did not differ significantly between sexes except in the 50 to 59years group (P=.0105). The ATR astigmatic change per decade did not differ significantly between men and women. Videokeratography maps revealed that the total and anterior corneal shape changed to ATR astigmatism with age in both sexes, and that this ATR change began at a younger age in male eyes than in female eyes. The posterior corneal shape did not differ between sexes at any age. Against-the-rule corneal astigmatism was greater and the ATR astigmatic change with age began earlier in the male eyes than in the female eyes, suggesting that target astigmatism should be determined separately for men and women when performing astigmatism correction.

Analysis of Corneal Astigmatism before Surgery in Chinese Congenital Ectopia Lentis Patients

ABSTRACTPurpose: This study aims to describe the characteristics of corneal astigmatism before surgery in congenital ectopia lentis (CEL) patients.Methods: This retrospective study reviewed 306 CEL patients from 1st January 2006 to 31st December 2015. One eye was randomly selected from each patient when the patient had bilateral EL. The influence of sex, laterality, and Marfan syndrome on corneal astigmatism in different age subgroups was evaluated and compared. The correlation between age and corneal astigmatism was evaluated.Results: Two hundred fifty-two eyes were included in this study. The mean corneal astigmatism of CEL patients was 2.00 ± 1.28 D. There was a statistical difference in corneal astigmatism between CEL eyes with and without Marfan syndrome. However, no statistical difference was found between male and female patients, or between the EL-affected eye and the unaffected eye in monocular EL patients. There was a positive correlation between age and corneal astigmatism in CEL eyes.Conclusions: This study suggests that CEL patients’ corneal astigmatism is higher in patients with Marfan syndrome, and corneal astigmatism of the CEL eye increases with age. Our results are useful for surgeons to make appropriate incision and intraocular lens (IOL) choices for patients, as well as a useful reference for designs of new IOLs.

Clear corneal incision of 2.75 mm for cataract surgery induces little change of astigmatism in eyes with low preoperative corneal cylinder.

To assess the early astigmatic effect induced by 2.75 mm clear cornea incisions with different locations for cataract surgery. A total of 146 eyes of different patients were studied prospectively. Cataract surgery was performed by three surgeons, two using a temporal approach and one using a superi-or approach. For both approaches, the site of the 2.75 mm incision was allowed to vary slightly according to the characteristics of the eye and orbit. Computerized videokeratography was used to measure corneal astigmatism before surgery and after 1, 4, and 12 weeks. Corneal astigmatism was recorded as cylinder and axis and it was then converted to 2 power vector. Model based prediction and comparisons were made for the most commonly used corneal incision sites: 12 (both eyes), 2 (left eye), and 8 (right eye) oclock meridian. After 3 months the differences in corneal astigmatism (JCC 0 ) between the incisions performed at 12 and 2 oclock were not statistically significant (-0.08, 95% CI: -0.19, -0.02); the differences in JCC 0 between incisions at 12 and 8 oclock were -0.17 (95% CI: -0.30, -0.05; p<0.01). After 3 months the change in JCC 0 for the patients with 0.5 D with-the-rule preoperatively were -0.32 (95% CI: -0.44, 0.21; p<0.01) for incisions at 12; -0.24 (95% CI: -0.36, 0.13; p<0.01) for incisions at 2; and -0.15 (95% CI: -0.27, -0.03; p<0.05) for incisions at 8. After 3 months the changes of JCC 0 for the patients with -0.5 D against-the-rule pre-operatively were 0.10 (95% CI: 0.04, 0.23) for incision at 12; 0.18 (95% CI: 0.04, 0.32; p<0.05) for incisions at 2; and 0.27 (95% CI: 0.14, 0.40; p<0.01) for incisions at 8 oclock. The oblique astigmatic vector (JCC 45 ) was very modest in this sample before surgery and underwent minimal and nonsignificant change after it. This study has shown that a 2.75 mm clear corneal incision causes a small change of corneal cylinder regardless of incision site.

Corneal astigmatism among 2 085 age-related cataract patients before surgery

Objective: To investigate the characteristics and distribution of corneal astigmatism before surgery among age-related cataract patients in the Hubei area. Methods: Retrospective study. From January 1, 2012 to July 31, 2016, IOL Master measurements of all qualified cataract surgery candidates were retrospectively collected. Descriptive statistical analysis was used to assess the degree, distribution and type of corneal astigmatism. Kolmogorov-Smirnov (K-S) test was used to evaluate the normal distribution of variables. One-way analysis of variance and Kruskal-Wallis test were applied for the comparison of variance for normally and non-normally distributed quantitative data among different age groups. Spearman's rank test was used to assess the relationship between age and corneal astigmatism. Results: The mean age of the 2 085 patients (3 586 eyes) involved was (73.1±9.43) years old, with more women (58.3%) than men. The mean value of corneal curvature was 44.33 D (95%CI: 44.28-44.39), and the mean corneal astigmatism was 1.06 D (range, 0.05 D to 6.74 D). K-S test indicated the distribution of corneal curvature was normal (P=0.18), while corneal astigmatism did not obey the normal distribution (P<0.01). Corneal astigmatism was between 0.25 D and 1.25 D in 67.7% of the eyes, >1.25 D in 29.7%, and<0.25 D in 4.2%. Corneal astigmatism degree increased with the age increase (P<0.01). There was no statistical difference in corneal astigmatism between women and men (P=0.075). However, women had steeper corneal curvatures than men with statistical difference (P<0.01). Corneal astigmatism with the rule was observed in 29.0% of the eyes, while astigmatism against the rule was found in 53.0%. And astigmatism against the rule increased with age. Conclusion: Corneal astigmatism mostly distributes between 0.25 D and 1.25 D in age-related cataract patients who lived in Hubei. Corneal astigmatism degree increased with age, and the dominant type was astigmatism against the rule. There was no difference in astigmatism between men and women patients aged 50 years and above, but in 70- to 79-year-old patients, women had a higher astigmatism degree than men. The corneal curvature of women was steeper than men in general and in each age group. (Chin J Ophthalmol, 2017, 53: 522-527).

Anisometropia of spherical equivalent and astigmatism among myopes: a 23-year follow-up study of prevalence and changes from childhood to adulthood.

To study anisometropia of spherical equivalent and astigmatism from the onset of myopia at school age to adulthood. A total of 240 myopic schoolchildren (mean age 10.9years), with no previous spectacles, were recruited during 1983-1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Examinations with subjective cyclopedic refraction were repeated 3years later (follow-up 1) for 238 subjects and thereafter at the mean ages of 23.2 (follow-up 2) and 33.9years (follow-up 3) for 178 and 134 subjects. After exclusions, the 102 subjects who attended all three follow-ups were included in the analyses. Corneal refractive power and astigmatism and anterior chamber depth was measured with Pentacam topography and axial length with IOL master at study end. Prevalence and changes in anisometropia of spherical equivalent (AnisoSE) and astigmatism (AnisoAST) and their relationships with refractive and axial measures were studied. Mean (±SD) of spherical equivalent (SE), AnisoSE and AnisoAST increased from baseline to follow-up end from -1.44±0.57 D to -5.11±2.23 D, from 0.28±0.30 D to 0.68±0.69 D and from 0.14±0.18 D to 0.37±0.36 D, respectively. Prevalence of AnioSE, ≥1 D, increased from 5% to 22.6% throughout follow-up. Higher AnisoSE was associated with SE in the less myopic eye at baseline and at follow-up 1, and with SE in the more myopic eye in follow-ups 2 and 3 in adulthood. At study end, AnisoSE was associated with the interocular difference in axial length (AL) (r=0.612, p<0.001) but not with the interocular difference in corneal refraction (CR) (r=-0.122, p=0.266). In cases of low AnisoSE(≤1.00 D), the negative correlation between the real interocular differences (value of right eye minus value of left eye) in CR and AL (r=-0.427, p<0.001) decreased the influence of the interocular difference in AL on AnisoSE, causing emmetropization in AnisoSE. The interocular difference in corneal astigmatism was the main factor associated with AnisoAST (r=0.231, p=0.020). No significant relationship was found between AnisoAST and level of SE. Anisometropia of the spherical equivalent (AnisoSE) increased along with the myopic progression and at study end was mainly associated with the interocular difference in AL. AnisoAST was mainly explained by the interocular difference in corneal astigmatism. In cases with low AnisoSE (≤1.0 D), the interrelationship between CR and AL decreased AnisoSE causing emmetropization in AnisoSE.

Comparison of iris-fixated foldable lens and scleral-fixated foldable lens implantation in eyes with insufficient capsular support.

To compare the outcomes of vision using two different intraocular lens (IOL) replacement techniques, iris-fixated foldable intraocular lens (IF-IOL) and scleral-fixated foldable intraocular lens (SF-IOL) in patients with insufficient capsular support. Total 63 eyes (62 patients) with insufficient posterior capsule support underwent replacement of IF-IOL or SF-IOL between January 2008 and August 2011. Outcome measures included changes in visual acuity, slit lamp examination, refractive indices and corneal curvatures. The mean improvement of uncorrected visual acuity (UCVA) was greater in IF-IOL group compared to the SF-IOL group (0.43 D±0.19 D vs 0.35 D±0.18 D, P<0.05). Moreover, 12 (38.71%) eyes in IF-IOL group and 4 (12.50%) in SF-IOL group had a higher postoperative UCVA than preoperative best corrected visual acuity (BCVA) while 9 (29.03%) eyes in IF-IOL group and 18 (56.25%) in SF-IOL group had a lower postoperative UCVA than preoperative BCVA. The myopic mean manifest sphere and mean cylinder magnitude were lower in the IF-IOL group than that in the SF-IOL group (-0.47 D±0.58 D vs 0.50 D±0.43 D, P<0.01; 0.84 D±0.53 D vs 1.23 D±0.70 D, P<0.05). No difference of corneal astigmatism and surgically induced astigmatism was found between the two groups. In addition, fewer complications were observed in IF-IOL eyes. IF-IOL implantation can give a significant improvement in vision with fewer complications than SF-IOL in patients with insufficient capsular support.

Comparison of keratometry and astigmatism measured by Pentacam and IOL Master

Objective To compare the difference of keratometry and astigmatism measured by Pentacam and IOL Master in age-related cataract operations. Methods The inspection of involved patients was taken by the same operator.The data of keratometry and corneal astigmatism were the average of three sets. Paired t tests ,A simple linear correlation analysis and the Bland-Altman method were used to evaluate the difference, correlation and agreement of keratometry respectively. Wilcoxon signed rank test and simple statistical analysis were performed to compare the difference of corneal astigmatism. Results The mean keratometry value were (44.14±1.49) D (male), (44.73±1.55) D (female) for Pentacam, and (44.27±1.50) D (male)、(44.86±1.56) D (female) for IOL Master. There was significant statistical difference in keratometry value both in the terms of instrument and sex.The correlation of keratometry was high(r=0.986). The absolute value of the maximum difference was 1.19 D in the 95% limits of agreement of Bland-Altman histogram. The astigmatism degree and axis were (0.77±0.52) D and (85.38±53.36)° for Pentacam, (0.90±0.61) D and (85.38±53.36)° for IOL Master.There was obivous statistical difference in astigmatism degree between the two instruments, while, no great difference in axis.The percent of astigmatism axis difference above 10° was 44.4%. Conclusions Both Pentacam and IOL Master can measure corneal curvature and astigmatism of cataract patients accurately.There are good correlation and poor consistency. Key words: Pentacam; IOL Master; Keratometry; Corneal astigmatism

Descemet Stripping Automated Endothelial Keratoplasty for Bullous Keratopathy With an Irregular Posterior Surface

To investigate the efficacy and safety of Descemet stripping automated endothelial keratoplasty (DSAEK) for bullous keratopathy with an irregular posterior surface of the cornea caused by anterior-posterior radial keratotomy or forceps injury. The results were compared with eyes that had undergone penetrating keratoplasty (PKP). Six eyes of 6 Japanese patients (mean age, 52.0 years) who underwent DSAEK between 2007 and 2012 were analyzed retrospectively. Of the 6 cases, 5 were birth injuries and 1 resulted from anterior-posterior keratotomy. Five of the 6 cases had mild-to-moderate amblyopia. The clinical results of DSAEK were compared with the outcomes of disease-matched cases treated with PKP [19 eyes of 18 patients (mean age, 58.4 years): 9 cases were birth injuries and 10 resulted from anterior-posterior keratotomy]. Subjective symptoms, graft clarity, best-corrected visual acuity, corneal astigmatism, postoperative endothelial cell density, posterior irregularity, and intraoperative and postoperative complications were evaluated. All grafts were attached successfully without double chamber formation following DSAEK. The corneas remained clear throughout the observation period, and the subjective symptoms improved in all cases. Significant improvement was observed in the best spectacle-corrected visual acuity and posterior irregularity in all the patients. No significant difference in corneal astigmatism was observed between the DSAEK and PKP groups. The mean endothelial cell density was 1450 cells per square millimeter 6 months postoperatively in the DSAEK group, which was similar to that in the PKP group. DSAEK is considered to be useful, even in bullous keratopathy eyes with an irregular posterior surface.

Comparison of Automated and Partial Coherence Keratometry and Resulting Choice of Toric IOL

Consistent astigmatism correction with implantation of a toric intraocular lens (IOL) requires accurate preoperative keratometry. This article compares corneal astigmatism determined by an autokeratometer (Topcon KR-7100) and a partial coherence interferometry keratometer (IOLMaster 500) and considers if any discrepancy ultimately alters in final cylindrical power of the toric IOL for implantation. Keratometry of 235 eyes was performed using both instruments. Corneal astigmatism was transformed into vector components J0 and J45 and cylindrical power at the IOL plane calculated. Comparisons were made using paired t test and correlation and Bland-Altman analyses. Although interinstrument differences for J0 (p = 0.013), J45 (p = 0.012), and toric IOL cylindrical power (p < 0.001) were statistically significant, a high correlation for these (R = 0.96, 0.90, and 0.90, respectively) was observed. IOLMaster tended to overestimate corneal astigmatism by 0.13 (±0.31) diopters and toric IOL cylinder by 0.11 (±0.18) diopters. Difference in calculated toric IOL cylindrical power correlated poorly with corneal curvature (R = 0.007) and astigmatism (R = -0.004). The two keratometers were generally concordant in measuring corneal astigmatism. However, the resultant choice of toric IOL cylinder power differed appreciably in 40% of eyes examined. Therefore, postoperative visual outcome with toric IOL implantation may be optimized by a thorough analysis of biometry data before IOL selection, paying special attention to any difference in corneal astigmatism as measured by more than one instrument.

Comparative analysis of three different calibers phacoemulsification needles in the clinical application

Objective To study and analyze the effect of using three sizes of phacoemulsification needles with different calibers in phacoemulsification on effective phacoemulsification time (EPT),corneal astigmatism in optic axis,corneal endothelial cell count,incidence of corneal edema and vision after phacoemulsification surgery.Methods The study included 180 age-related cataract eyes of 167 cases,which matched Grade Ⅲ nucleus (Emery criterion).They were divided into 3 groups randomly,who underwent phacoemulcification with different needles.In Group A the 18G needles were used,Group B 19G,Group C 20G.Each group was used the same kind of phacoemulsification needle and incision.The EPT,the change of corneal endothelial cell count,the corneal edema incidence at 1 day after surgey,the corneal astigmatism in optic axis and the vision were recorded after surgery.The patients were followed up for 3 months.Results There were statistically significant differences among three groups in EPT (P ＜ 0.05).There was a statistically significant change in postoperative corneal endothelial cell count in group B and group C (P ＜ 0.05),but not in group A(P ＞ 0.05).There were statistically significant differences between the three group in corneal edema incidence at 1 day after the surgery (P ＜ 0.05).The differences in corneal astigmatism in optic axis among the three groups at 1 week after the surgery were statistically significant (P ＜ 0.05),but not at 1 m and 3ms postoperatively(P ＞ 0.05).There were statistically significant differences in vision at 1 d,1w,1 ms after the surgery among three groups (P ＜ 0.05),but there were no significant differences at 3 month postoperatively(P ＞ 0.05).Conclusion While using three sizes of phacoemulsification needles with different calibers in phacoemulsification,we found that for the same nuclear hardness,the smaller caliber used in the surgery,the longer EPT we needed and the poorer efficiency of phacoemulsification.It may lead to lower corneal endothelial cell count and severer corneal endothelium hurt.Moreover,the edema of incision will increase the incidence of corneal astigmatism in early stage after surgery. Key words: Cataract; Phacoemulsification needle; Caliber; Corneal astigmatism; Optic axis; Vision, after surgery