Biometry and corneal astigmatism in cataract surgery candidates from Southern China

Correlation of Ocular Biometry with Axial Length in Elderly Japanese

Purpose

Ocular parameters are not only useful for diagnosing diseases but also for guiding treatment approaches. A lot of previous studies have reported ocular parameters and its relations before cataract surgery. However, despite ethnic differences in ocular biometry, few reports have dealt with Japanese. Hence, this retrospective cross-sectional study aimed to measure parameters of preoperative cataract patients and examines the correlations between each parameter in Japanese elderly people.

Patients and Methods

The 210 subjects had their ocular axial lengths measured with OA-2000. The endpoints were ocular axial length (AL), central corneal thickness (CCT), average anterior corneal radius of curvature (CR), white-to-white (WTW), anterior chamber depth (ACD), and lens thickness (LT). Our analyses utilized the eye with the longer AL in each person. Each parameter was analyzed for correlations in a round-robin manner. Regression analyses were performed on parameters correlated with AL.

Results

The parameters correlated with AL were CR (r = 0.33, P < 0.0001), WTW (r = 0.29, P < 0.0001), ACD (r = 0.59, P < 0.0001), and LT (r = -0.30, P < 0.0001). These parameters related to AL in all simple regression equations (CR (P < 0.0001), WTW (P = 0.0002), ACD (P < 0.0001), LT (P = 0.0001)). In multiple regression analyses, CR, ACD, and LT might relate to AL (CR (P = 0.0002), ACD (P < 0.0001), LT (P = 0.018)). LT tended to be thinner as AL increased, while CR, WTW, and ACD tended to increase.

Conclusion

This information may be useful in developing strategies for ophthalmic surgery, as it provides information on the location of intraocular tissues. Various parameters have been used in intraocular lens (IOL) power calculations in recent years and knowledge of the interrelationship among parameters may be useful in determining IOL power according to ethnicity in the future.

Gender- and Age-Related Differences of Ocular Biometric Parameters in Patients Undergoing Cataract Surgery in Bosnia and Herzegovina

Purpose

The aim of the study is to determine the distribution and mutual relationship of ocular biometric parameters, as well as to evaluate gender- and age-related differences in patients undergoing cataract surgery in Bosnia and Herzegovina.

Materials and Methods

It was a retrospective cross-sectional study of consecutive patients who underwent cataract surgery between January 2017 and December 2021 in a tertiary care clinic. All biometric measurements were performed using the optical biometer OA-2000 (Tomey, Nagoya, Japan).

Results

The study evaluated 1278 eyes from 1278 consecutive cataract patients. The average age of all included patients was 69.4 ± 9.98 (range 40-96). A total of 672 eyes (52.58%) were from females. The mean axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and mean keratometry were 23.46 ± 1.18 mm, 3.17 ± 0.40 mm, 4.54 ± 0.48 mm, and 43.42 ± 1.55D, respectively. Corneal astigmatism of ≥1D, >2D and >3D was found in 33.4%, 7.8% and 2.5% patients, respectively. Females were found to have shorter AL (p < 0.0001), shallower ACD (p < 0.0001) and steeper corneas (p < 0.0001). In both genders, AL, ACD and with the rule astigmatism showed a decreasing trend (p = 0.0001), while keratometry, the average cylinder, and against the rule astigmatism showed an increasing trend (p = 0.0001) with increasing age. Furthermore, in both genders, there was an increasing trend in ACD (p = 0.0001), and a decreasing trend in keratometry (p = 0.0001) and LT (p = 0.0001) with increasing AL.

Conclusions

This study provides useful reference data on ocular biometry for cataract surgeons in Bosnia and Herzegovina. Female patients tend to have steeper corneas, shorter AL and shallower AC than males, and these differences are independent of age or AL.

Comparison of astigmatism correction and visual outcomes in mix-and-match implantations of trifocal intraocular lenses with femtosecond laser-assisted arcuate keratotomy and contralateral bifocal Toric intraocular lenses

Introduction

Astigmatism reduces the postoperative visual performance after non-toric intraocular lenses (IOLs) implantation, and limits the use of refractive IOLs in cataract surgery. The purpose of this study was to compare the efficacy in astigmatism correction and the postoperative visual outcomes between the implantation of a trifocal IOL with femtosecond laser-assisted arcuate keratotomy (FSAK) in one eye and a bifocal toric IOL (TIOL) in the other, in patients with cataract and moderate astigmatism.

Methods

This prospective observational paired-eye study enrolled patients with cataract and corneal astigmatism (CA) between 0.75 and 2.25 D in both eyes. The patients underwent a mix-and-match treatment comprising trifocal IOL implantation with FSAK and bifocal TIOL implantation. We compared the visual acuity (VA) at all distances, defocus curve, postoperative refractive astigmatism (RfA), CA, high-order aberrations, modulation transfer function (MTF) curve, and Strehl ratio between the two eye groups.

Results

In total, 41 patients (82 eyes) were enrolled and completed a 6-month follow-up. The 1- and 3-month uncorrected distance VA and 3-month uncorrected near VA were greater in eyes with bifocal TIOLs than with trifocal IOLs and FSAK (p = 0.036, 0.010, and 0.030, respectively), whereas the latter had greater uncorrected intermediate VA at every visit and greater VA in the intermediate range of defocus curve (at -1.50 and - 2.00 D) than the eyes with bifocal TIOLs. The postoperative RA of the eyes with trifocal IOL and FSAK was significantly higher than that of the bifocal TIOL-implanted eyes at the 3- and 6-month follow-ups.

Discussion

Both FSAK and TIOL implantation effectively reduce pre-existing moderate astigmatism in patients with cataract. The eyes with bifocal TIOLs had more stable long-term astigmatism correction, whereas those with trifocal IOLs and FSAK had better intermediate VA. Therefore, a mix-and-match implantation of trifocal IOL with FSAK and contralateral bifocal TIOL could achieve effective astigmatism correction and provide an overall optimal VA.

Distribution and Characteristics of Ocular Biometric Parameters among a Chinese Population: A Hospital-Based Study

INTRODUCTION

This study aimed to describe the distribution and characteristics of ocular biometric parameters among a large Chinese population.

METHODS

This retrospective cross-sectional study included 146,748 subjects whose ocular biometric parameters were measured at the ophthalmology clinic of West China Hospital, Sichuan University, and recorded in the hospital database. Ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, were recorded. Only monocular data for each subject were analyzed to avoid bias.

RESULTS

Valid data from 85,770 subjects (43,552 females and 42,218 males) aged 3-114 years were included in this study. The mean axial length, mean anterior chamber depth, average corneal keratometry, and mean keratometric astigmatism were 24.61 mm, 3.30 mm, 43.76 D, and 1.19 D, respectively. The stratification of the ocular parameters by age and gender showed significant inter-gender and inter-age differences.

CONCLUSIONS

Analysis of a large population of subjects in western China aged 3-114 years showed that the distribution and characteristics of ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, differed by age and gender. This study is the first to describe ocular biometric parameters in subjects aged > 100 years.

SS-OCT-based ocular biometry in an adult Korean population with cataract

PURPOSE

To evaluate the characteristics of ocular biometric parameters in adult Korean patients with cataract.

SETTING

Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.

DESIGN

Retrospective case series.

METHODS

Ocular biometric values of 5273 eyes of 5273 Korean patients undergoing cataract surgery measured with the IOLMaster 700 at the Seoul National University Hospital between November 2019 and December 2021 were reviewed.

RESULTS

A total of 5273 eyes of 5273 Korean patients were analyzed. The mean ± SD age was 66.1 ± 12.8 years, and 62% were female. Overall, age and ocular biometric parameters were correlated with each other. Particularly, age showed a negative correlation with anterior chamber depth (ACD; r = -0.357), axial length (AL; r = -0.344), and posterior keratometry (PK; r = -0.054) and a positive correlation with lens thickness (LT; r = 0.484), angle α ( r = 0.194), total keratometry (TK; r = 0.137), anterior keratometry (AK; r = 0.129), and angle κ ( r = 0.071). AL showed a positive correlation with ACD ( r = 0.503) and PK ( r = 0.339) and a negative correlation with AK ( r = -0.342), TK ( r = -0.334), LT ( r = -0.288), angle α ( r = -0.220), and angle κ ( r = -0.040). With age, anterior and total corneal astigmatism changed from with-the-rule (WTR) to against-the-rule (ATR) astigmatism. Posterior corneal astigmatism was ATR regardless of age; however, the magnitude decreased with age.

CONCLUSIONS

Age showed a significant correlation in the order of LT, ACD, and AL. With age, angle α and κ increased, and total corneal astigmatism changes from WTR to ATR, which is mainly affected by changes in anterior corneal astigmatism. AL showed a significant correlation in the order of ACD, AK, PK, and TK. These data are pertinent for improving the result after cataract surgery, especially when using premium intraocular lenses.

Epidemiology and Burden of Astigmatism: A Systematic Literature Review

SIGNIFICANCE

This is the first literature review to report the epidemiology, patient burden, and economic burden of astigmatism in the general adult population. The unmet needs of astigmatism patients with coexisting ocular conditions (cataract, glaucoma, dry eye, presbyopia, or macular degeneration) and risks associated with untreated astigmatism are also reviewed and reported.

PURPOSE

This study aimed to identify, report, and summarize the published literature on epidemiology, patient burden, and economic burden of astigmatism using a systematic literature review.

METHODS

MEDLINE, EMBASE, and Cochrane Library databases were searched (January 1996 to May 2021). Search results were limited to the English language. Proceedings (2018 to 2021) from ophthalmology congresses were searched along with gray literature using the Google Scholar platform.

RESULTS

The literature search yielded 6804 citations, of which 125 met the inclusion criteria (epidemiology, 68; patient burden, 60; economic burden, 6). Astigmatism prevalence in the general population varied from 8 to 62%, with higher rates in individuals 70 years or older. The prevalence of with-the-rule astigmatism was higher in individuals 40 years or younger, whereas rates of against-the-rule and oblique astigmatism increased with age. Astigmatic patients experienced decreased vision quality, increased glare (53 to 77%), haloes (28 to 80%), night-time driving difficulties (66%), falls, and spectacle dependence (45 to 85%). Astigmatic patients performed vision-related tasks slower (1 D, 9% slower; 2 D, 29% slower) and made more errors (1 D, 38% more errors; 2 D, 370% more errors) compared with fully corrected individuals. In cataract patients with astigmatism, the annual mean per-patient productivity loss costs ranged from €55 ($71) to €84 ($108), and mean informal care costs ranged from €30 ($39) to €55 ($71) with a mean of 2.3 to 4.1 hours spent on informal care.

CONCLUSIONS

Uncorrected astigmatism decreases patients' vision-related quality of life, decreases productivity among working-age adults, and poses an economic burden on patients and their families.

Correction of Asymmetric Bowtie Corneal Astigmatism with a Toric Intraocular Lens: Outcomes and Accuracy of Measurement Modes

The outcomes of toric intraocular lens (IOL) implantation in correcting asymmetric bowtie corneal astigmatism remain uncertain. The accurate measurement of corneal astigmatism is essential for surgical planning. In this prospective cohort study, patients with asymmetric or symmetric bowtie corneal astigmatism who underwent toric IOL implantation were recruited. Preoperative corneal astigmatism was measured with an IOLMaster and Pentacam (including the simulated keratometry (SimK), total corneal refractive power (TCRP), and wavefront aberration (WFA) modes). At 3 months after surgery, the refractive outcomes and residual astigmatic refractive errors were compared with patients with symmetric bowtie astigmatism. The prediction errors (the differences between the calculated actual corneal astigmatism and the measured corneal astigmatism) were compared among the different measurement modes in the asymmetric group. There were no differences in residual astigmatism between the asymmetric and symmetric groups. However, the mean absolute residual astigmatic refractive error was greater in the asymmetric group than in the symmetric group (0.72 ± 0.42 D vs. 0.53 ± 0.24 D, p = 0.043). In the asymmetric group, the mean absolute prediction errors for the IOLMaster, SimK, TCRP and WFA modes were 0.53 ± 0.40, 0.56 ± 0.47, 0.68 ± 0.52, and 0.43 ± 0.40 D, respectively. The Pentacam WFA mode was the most accurate mode (p < 0.05). The absolute prediction error of the WFA mode was positively correlated with the total corneal irregular astigmatism higher-order aberrations and coma (r = 0.416 and r = 0.473, respectively; both p < 0.05). Our study suggests toric IOL implantation effectively corrected asymmetric bowtie corneal astigmatism. The Pentacam WFA mode may be the most accurate measurement mode, although its accuracy decreased as asymmetry increased.

Anterior chamber parameters in cataract surgery candidates from middle China

To determine the distribution of the anterior chamber parameters and associated factors in cataractous adults from middle China. In this cross-sectional study, axial length, anterior chamber depth (ACD) and lens thickness (LT) were measured with IOLMaster 700. The Pentacam HR was designed to measure the anterior chamber volume (ACV) and anterior chamber angle (ACA). Patients' data were collected and analyzed between 2020 and 2022. A total of 157 eyes of 157 Chinese adults (mean age: 64.43 ± 12.16 years) with a cataract were enrolled in this study. The mean values measured were as follows: axial length, 24.10 ± 2.44mm; ACD, 2.99 ± 0.52 mm; LT, 4.51 ± 0.48 mm; ACV, 113.98 ± 45.12 mm3; ACA, 32.33 ± 7.66 degrees. The ACD and ACV were statistically significantly greater in men than in women and had a decrease trend as age and LT increased. In the simulated linear equation of age with ACD and LT the absolute slope coefficients of equations were the same; however, the directions were opposite. The mean ACV was <100 mm3 when the patients were over 60 years. In the multivariate regression analysis of ACD, ACV and ACA there was a reasonable prediction with adjusted R2 = 0.878, 0.847 and 0.564, respectively. This study may provide normative data for cataract patients. The profile of anterior chamber can help improve the knowledge of the risk of angle closure in cataract candidates.

Ocular Biometric Values and Prevalence of Corneal Astigmatism in Patients Candidate for Cataract Surgery

Purpose

To analyze the biometric values and the prevalence of corneal astigmatism in cataract surgery candidates.

Methods

This is a prospective study. Ocular biometric values and corneal keratometric astigmatism were measured by optical low-coherence reflectometry (Lenstar LS 900) before surgery in patients who were candidates for cataract extraction surgery. Descriptive measurements of biometric dimensions and keratometric cylinder data and their correlations with sex and age were evaluated.

Results

Ocular biometric and keratometric values from 2084 eyes of 2084 patients (mean age 66.43, range 19-95 years) were analyzed. The mean values were as follows: corneal astigmatism 0.89 diopter (D), mean corneal keratometry 44.29 D, central corneal thickness 534 μ, internal anterior chamber depth (ACD) 3.11 mm, lens thickness 4.50 mm, and axial length 23.35 mm. Corneal astigmatism was <1.25 D in 1660 (79.5%) of eyes. Astigmatism was with-the-rule in 976 (46.8%) of eyes, against-the-rule (ATR) in 702 (33.7%), and oblique in 406 (19.5%). Analysis of corneal astigmatism revealed a change toward "ATR" with age which was not statistically significant. The ACD was correlated with age. The amount of corneal astigmatism had no correlation with age and sex.

Conclusion

Corneal astigmatism was higher than 1.25 D in about 21% of cataract surgery candidates with slight differences between the various age ranges and had no correlation with age and sex.

Distribution of Ocular Anterior and Posterior Segment Lengths Among a Cataract Surgical Population in Shanghai

Purpose: To investigate the distributions of the ocular anterior and posterior segment lengths among a cataract surgical population in Shanghai. Design: Cross-sectional study. Methods: Ocular biometric parameters of 23,462 eyes of 23,462 cataract surgery candidates were reviewed. Axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) were obtained using IOL Master. Anterior segment length (ASL = ACD + LT), posterior segment length (PSL = AL - ASL) and the ratio of ASL to PSL (ASL/PSL) were calculated. Results: The mean ASL was 7.58 ± 0.39 mm, the mean PSL was 17.12 ± 2.64 mm. As the age grew, the ASL increased, and PSL increased firstly then decreased. Male subjects tended to have significantly longer ASL and shorter PSL than female subjects. With the increasing AL, the ASL was firstly decreased to trough at 20-22 mm AL group, then increased gradually, while the PSL increased rapidly. The ASL correlated positively with AL in normal, moderate and highly myopic eyes, negatively in short eyes. The PSL correlated positively with AL across the entire study population. The ASL/PSL was not constant in the eyes with different AL but had a relatively steep downward trend with the increasing AL in the short eyes, then decreased smoothly in normal, moderate and highly myopic eyes. Conclusions: In Chinese cataractous eyes, longer ASL and shorter PSL were associated with elder age and male gender. The change of ASL over AL was not linear, and the ASL was smallest in the eyes with AL of 20-22 mm. The elongation of the eyeball was mainly due to the extension of the posterior segment.

Comparison of intraocular lens power formulas according to axial length after myopic corneal laser refractive surgery

PURPOSE

To assess the predictive accuracy of 4 no-history intraocular lens (IOL) power formulas in eyes with prior myopic excimer laser surgery, classified in 4 groups according to their axial length (AL), and investigate the relationship between AL and predictive accuracy.

SETTING

Seoul St. Mary's Hospital, Republic of Korea.

DESIGN

Retrospective case series.

METHODS

IOL power was calculated with the Barrett True-K, Haigis-L, Shammas-PL, and Triple-S formulas in 4 groups classified according to AL. Primary outcomes were the median absolute error (MedAE) and percentage of eyes with a prediction error (PE) within ±0.50 diopter (D).

RESULTS

This study included 107 eyes of 107 patients. The Barrett True-K had the lowest MedAE when AL was <26.0 mm (0.30 D) and between 26.0 and 28.0 mm (0.54 D); in these subgroups, it had the highest percentages with a PE within ±0.50 D (71.4% and 46.2%). For AL between 28.0 and 30.0 mm, the Triple-S method showed the lowest MedAE (0.43 D) and highest percentage with a PE within ±0.50 D (58.3%). For AL ≥30.0 mm, the Shammas-PL formula produced the lowest MedAE (0.41 D) and highest percentage with a PE within ±0.50 D (58.3%). The Barrett True-K was the only formula with a correlation between AL and PE (r = -0.219/P = .023).

CONCLUSIONS

The predictive accuracy of no-history IOL formulas depends on the AL. The Barrett True-K had the highest accuracy when AL was < 28.0 mm and the Triple-S when it ranged from 28.0 mm to 30.0 mm, whereas the Shammas-PL was more accurate when AL was ≥30.0 mm.

Distribution and internal correlations of corneal astigmatism in cataract patients

The aim of the study is to explore the distribution patterns and internal correlations of the morphological parameters of the cornea in patients with age-related cataract. The Pentacam HR was used to measure anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), total corneal astigmatism (TCA) and keratometric corneal astigmatism (KCA). With age, the proportion of with-the-rule (WTR) ACA decreased from 65.31% to 23.63%, while the against-the-rule (ATR) ACA increased from 26.53% to 56.20%. PCA exceeded 0.50 D in 9.14% of eyes, while 76.35% of them were ATR. The magnitude of ACA was positively correlated with PCA in the whole sample, with a more significant correlation in WTR eyes (s_r = 0.349, P < 0.001). The vector summation effect of PCA to ACA changed from compensation to augmentation with aging. In 57.53% of WTR eyes, KCA was overestimated by an average of 0.21 ± 0.17 D, while it was underestimated by 0.38 ± 0.27 D in 87.62% of ATR eyes. In conclusion, among age-related cataract patients, ACA and TCA gradually shifted from WTR to ATR with aging, while most PCA remained as ATR. Ignoring the age-related changes and real PCA might cause overestimation of WTR astigmatism and underestimation of ATR astigmatism.

Distribution of ocular biometric parameters and optimal model of anterior chamber depth regression in 28,709 adult cataract patients in China using swept-source optical biometry

Background

The purpose of this study was to evaluate the ocular biometric parameters in adult cataract patients from China and create an anterior chamber depth (ACD) regression model.

Methods

The ocular biometric records of 28,709 right eyes of cataract surgery candidates who were treated at Aier Eye Hospitals in nine cities from 2018 to 2019 were retrospectively analyzed. All measurements were taken with IOLMaster 700. We included patients who were at least 40 years old and were diagnosed with cataract.

Results

The mean age of the patients was 68.6 ± 11.0 years. The mean values recorded were as follows: axial length (AL), 24.17 ± 2.47 mm; mean keratometry (Km) value, 44.26 ± 1.70 D; corneal astigmatism (CA), 1.06 ± 0.96 D; ACD, 3.02 ± 0.45 mm; lens thickness (LT), 4.52 ± 0.45 mm; central corneal thickness (CCT), 0.534 ± 0.04 mm; and white to white (WTW) corneal diameter, 11.64 ± 0.46 mm. ACD correlated positively with AL (Spearman coefficient, 0.544) and WTW (0.300), but negatively with LT (-0.660) and age (-0.285) (all P < 0.01). In the multivariate regression analysis of ACD, which included LT, AL, WTW, sex, Km, CCT, and age, there was a reasonable prediction with adjusted R² = 0.641.

Conclusions

Cataract patients with longer AL and wider WTW have deeper ACD. With increasing age and lens thickening ACD becomes shallower. Based on the standardized coefficients of ACD multivariate regression analysis from the study, LT is the main factor that affects ACD, and is followed by AL.

To compare on-axis measurements of the axial length with off-axis measurements in the paracentral horizontal and vertical positions

Purpose: To compare on-axis measurements of the axial length (AL) with off-axis measurements in the paracentral horizontal and vertical positions using the Lenstar LS 900 biometer.Methods: In this, the samples were selected from patients scheduled for cataract surgery using a systematic randomization method. After applying the exclusion criteria, all subjects underwent optometric examinations and AL measurement using the Lenstar. Five consecutive, non-cycloplegic measurements were done on the right eye centrally, 10° temporally, 10° nasally, 10° superiorly and 10° inferiorly on the retina by the same examiner.Results: Two hundred and seven eyes were examined in this study, of which 126 (60%) were for female patients. The mean age of the participants was 64.32 ± 10.77 years (range: 34-91 years). The mean central, superior, inferior, temporal, and nasal axial AL was 23.22 ± 1.02, 23.21 ± 1.02, 23.21 ± 1.02, 23.21 ± 1.02, 23.20 ± 1.03, respectively. Comparison of these readings using repeated measures ANOVA showed a statistically significant difference in the AL value among these positions. According to the post-hoc results, superior and nasal AL was statistically significantly lower compared to the central AL.Conclusion: If on-axis biometry is not available, AL can be measured in an off-axis manner in the paracentral temporal, superior and inferior positions. Considering the marked difference in AL measurement between central and nasal positions, off-axis measurement is not recommended in the nasal part because it may be associated with a marked hyperopic shift after cataract surgery.

Evaluation of preoperative corneal astigmatism using swept-source optical biometry in Chinese cataract surgery candidates with high myopia: a prospective, comparative observational study

Background

High myopia and cataracts are major causes of blindness in East and Southeast Asia. Corneal astigmatism is a major contributor to uncorrected poor vision after cataract surgery in patients with high myopia. The purpose of the present study was to evaluate the demographic characteristics and distribution of preoperative corneal astigmatism in Chinese cataract surgery candidates with high myopia.

Methods

Swept-source optical coherence tomography-based optical biometry was performed preoperatively in consecutive cataract surgery candidates who were classified by axial length (AL) into a high myopia group (defined as AL ≥26.0 mm) and a control group (normal ALs). The demographics, ALs, and keratometry values were recorded.

Results

Among 15,063 cataract surgery candidates (15,063 eyes), 1,921 patients (12.8%, 1,921 eyes) in the high myopia group and 11,880 patients (11,880 eyes) in the control group were enrolled. In the high myopia group, the mean age was 59.8±12.6 (standard deviation) years, which was younger than that in the control group (69.1±11.0 years, P<0.001). In the high myopia group, the mean corneal astigmatism was 1.20±0.83 dioptre (D), which was greater than that in the control group (0.93±0.69 D, P<0.001). In the high myopia group, 82.2% had corneal astigmatism ≥0.50 D, 51.4% ≥1.00 D, 27.4% ≥1.50 D and 14.4% ≥2.00 D, all of which were higher than the respective proportions in the control group (P<0.001 for all). In the high myopia group, 66.8% had moderate to high corneal astigmatism, and 42.8% had “with-the-rule” astigmatism, and both of these proportions were higher than the respective proportions in the control group (P<0.001 for both). In the high myopia group, corneal astigmatism tended to increase with increasing age (r =0.134, P<0.001) after the age of 50, which was consistent with the tendency in the control group.

Conclusions

A significant burden of preoperative corneal astigmatism was observed in Chinese cataract surgery candidates with high myopia. Moderate to high corneal astigmatism was more common in highly myopic eyes than in normal AL eyes.

Comparison of Ocular Biometry Profiles in Urban and Rural Cataract Candidates in Eastern China

Purpose

To compare ocular biometric parameters between urban and rural cataract patients in Shanghai, China.

Methods

A study of ocular biometry records from urban and rural hospitals was performed for cataract patients at least 50 years of age. The ocular biometrical parameters, which were measured with partial coherence laser interferometry (IOL Master, Zeiss), were axial length (AL), anterior chamber depth (ACD), radius of corneal curvature (K, including steep/flat/average K), astigmatism, and axis. Only the right eye record of each patient was analysed.

Results

Ocular biometric data included 2839 urban patients (73.15 ± 9.54 years) and 2646 rural patients (73.64 ± 7.32 years). Mean AL, ACD, and K were 24.35 ± 2.34 mm, 3.14 ± 0.58 mm, and 44.38 ± 1.52 D, respectively, in urban patients and 23.58 ± 1.70 mm, 3.08 ± 0.57 mm, and 44.53 ± 1.50 D, respectively, in rural patients. The urban subjects had significantly longer axial lengths (in both univariate and multivariate linear regression analyses) and deeper ACDs (in univariate analysis) than rural subjects (p < 0.01). There was no significant difference in steep K, flat K, and average K between the two groups. With-the-rule (WTR) corneal astigmatism was found in 1787 eyes (32.58%), against-the-rule (ATR) corneal astigmatism was found in 2727 eyes (49.72%), and oblique corneal astigmatism was found in 971 eyes (17.70%).

Conclusions

We report biometry and astigmatism data in a large cohort of urban and rural adult subjects for the first time. In our study, a short AL, shallow ACD, and axis turned in an ATR direction had higher prevalence rates in the rural subjects. This profile of ocular biometric data and corneal astigmatism will be helpful in planning for intraocular lens (IOL) power calculations and astigmatism correction in subjects in different locations.

Prevalence and Age-Related Changes of Corneal Astigmatism in Patients Undergoing Cataract Surgery in Northern China

Purpose

To examine the magnitude, orientation, and age-related changes of corneal astigmatism of the eyes before cataract surgery. Setting. Hebei Eye Hospital, Hebei, China.

Design

A clinical-based retrospective study.

Results

The study consisted of 5662 eyes of 5662 consecutive cataract surgery patients with a mean age of 68.26 ± 10.39 (mean ± standard deviation (SD)) years (range 40 to 97 years), and 59.86% of the patients were women. Mean corneal astigmatism was 0.98 ± 0.76 diopter (D) (range 0.00-9.61 D). Corneal astigmatism of 0.50-0.99 D was the most common range of values (30.08%), followed by 1.00-1.49 D (22.15%), ≤0.50 D (21.21%), and 1.50-1.99 D (10.28%). There was a strong U-shaped relation between corneal astigmatism and age (p for nonlinearity <.01). With the increase of age, the astigmatism axis gradually changes from with-the-rule (WTR) to against-the-rule (ATR). Moreover, in young patients with age below 65 years, WTR astigmatism was negatively correlated with age, while ATR was positively correlated with age (r = -0.11, p=.001; r = 0.10, p=.010, respectively). However, in the old patients with age above and equal to 65 years, all types of astigmatism were positively correlated with age.

Conclusion

This study may provide valuable and practical information to surgeons when selecting the appropriate surgical method and toric intraocular lens (IOLs).

Comparison of Anterior Ocular Biometric Measurements Using Swept-Source and Time-Domain Optical Coherence Tomography

Purpose

To compare central corneal thickness (CCT), aqueous depth (AQD), and anterior chamber depth (ACD) measurements using the swept-source (CASIA SS-1000, Tomey, Japan) and time-domain (Visante, Carl Zeiss Meditec, USA) anterior segment optical coherence tomographers (OCT) in normal eyes.

Methods

Sixty-eight eyes of 68 subjects were included. Three consecutive scans of each subject were obtained using both devices in a random order by one experienced operator. Standard deviation (S _w), coefficient of repeatability (CoR), coefficients of variation (CoV), and intraclass correlation coefficients (ICC) were used to evaluate the intraoperator repeatability. Agreement was assessed using the Bland-Altman plots and 95% limits of agreement (LoA).

Results

All measurements of the swept-source OCT (SS-OCT) and time-domain OCT (TD-OCT) showed high repeatability with low CoR (CCT: 2.34 μm and 6.16 μm; AQD: 0.05 mm and 0.09 mm; ACD: 0.06 mm and 0.09 mm), low CoV (CCT: 0.16% and 0.42%; AQD: 0.61% and 0.97%; ACD: 0.53% and 0.83%), and high ICC (>0.98). The mean CCT with SS-OCT was slightly thicker than the results with TD-OCT (difference = 4.55 ± 2.62 μm, P < 0.001). There was no statistically significant difference in AQD or ACD measurements between the two devices (0.01 ± 0.05 mm, P=0.111; 0.02 ± 0.05 mm, P=0.022, respectively). The 95% LoA between the SS-OCT and TD-OCT were -0.59 to 9.69 μm for CCT, -0.10 to 0.12 mm for AQD, and -0.09 to 0.12 mm for ACD.

Conclusions

High levels of repeatability and agreement were found between the two devices for all three parameters, suggesting interchangeability. SS-OCT demonstrated superior repeatability compared with TD-OCT.

Pattern of corneal astigmatism induced by primary pterygium in patients with cataract in a secondary hospital in Southern China: a cross-sectional study

OBJECTIVES

To review the pattern of primary pterygium-induced corneal astigmatism in patients with cataract in a southern Chinese population.

DESIGN

Clinic-based cross-sectional retrospective study.

SETTING

A secondary hospital at southern China.

PARTICIPANTS

A group of 1689 eyes with primary pterygium (PT group) and the other group of 4062 eyes without pterygium (NPT group) were included.

MAIN OUTCOME MEASURES

Corneal power was measured by an autokeratorefractometer. Corneal astigmatism was calculated as the difference in corneal power between the steepest and flattest meridians. Distribution of corneal astigmatism was compared between eyes with pterygium and eyes without pterygium.

RESULTS

Distribution of corneal astigmatism was different between PT group (skewness=2.548, kurtosis=8.237) and NPT group (skewness=2.778, kurtosis=15.52). Mean corneal astigmatism was significantly higher in the PT group (1.62±1.49D) compared with the NPT group (1.17±0.89D, p<0.0001). The prevalence of corneal astigmatism >1D (PT 52.3%, NPT 40.9%, p<0.0001), >2D (PT 22.4%, NPT 10.6%, p<0.0001) or >3D (PT 10.5%, NPT 3.2%, p<0.0001) was significantly higher in the PT group compared with the NPT group. Eyes in the PT group had significantly higher corneal astigmatism than the NPT group in almost every age group (all p<0.05), with the exception of patients ≥90 years. Moreover, eyes in the PT group had significantly higher with-the-rule (PT 1.72±1.59D, NPT 1.19±0.88D, p<0.0001) and against-the-rule (PT 1.63±1.46D, NPT 1.18±0.88D, p<0.0001) but similar oblique astigmatism (PT 1.11±1.00D, NPT 0.99±0.89D, p=0.065) corneal astigmatism compared with the NPT group. Power vector analysis indicated that the axis of corneal astigmatism was not significantly different between the two groups (J₀, PT -0.01±0.74D, NPT 0.01±0.52D, p=0.48; J₄₅, PT -0.03±0.82D, NPT 0.00±0.52D, p=0.54).

CONCLUSIONS

Pattern of corneal astigmatism in eyes with cataract and coexisting primary pterygium was different from eyes without pterygium. Pterygium is associated with higher magnitude but not different axis of corneal astigmatism.

Ocular biometry characteristics and corneal astigmatisms in cataract surgery candidates at a tertiary care center in North-East India

Purpose:

The purpose of this study is to determine the ocular biometry characteristics and corneal astigmatisms using partial coherence laser interferometry in patients aged 40 years or above undergoing cataract surgery in a medical college in North-East India.

Methods:

In a hospital-based cross-sectional study, ocular biometry characteristics such as axial length (AL), anterior chamber depth (ACD), white-to-white (WTW) diameter, corneal power (K), and corneal astigmatisms (D) of consecutive eligible cataract patients in a medical college in North-East India between January 2015 and December 2017 were determined using the intraocular lens (IOL) master. Height and weight were also measured.

Results:

A cross-sectional study evaluated ocular biometry characteristics of 641 eyes in 641 eligible patients. The mean age was 64.04 ± 10.81 years. The mean AL, ACD, WTW, corneal power, IOL power, and body mass index (BMI) were 23.34 ± 1.12 mm, 3.12 ± 0.39 mm, 11.92 ± 0.54 mm, 44.41 ± 1.50 diopter (D), 20.53 ± 2.79 D, and 26.12 ± 4.32, respectively. Against-the-rule, with-the-rule, and oblique astigmatisms were 48.4%, 33.2%, and 18.4%, respectively. Corneal astigmatism of ≥1 D was found in 292 eyes (45.55%) and >1.5 D in 182 eyes (28.39%). AL had statistically significant correlation with ACD, WTW, K, IOL power, height and weight but not with age. By multivariate analysis, AL was found to be associated with ACD, WTW, K and IOL power (P ≤ 0.05). The mean AL was negatively correlated with the mean K (R-square 0.138).

Conclusion:

This study is likely to provide the initial normative data for ocular biometry values in Indian adults 40 years or above, because such data is lacking in Indians using the IOL master. This will also help ophthalmologists in planning and improving the quality of surgical outcomes in phacoemulsification and phacorefractive surgeries by choosing the appropriate IOL and incision location.

Preoperative biometric measurements with anterior segment optical coherence tomography and prediction of postoperative intraocular lens position

The purpose of this study is to evaluate the biometric parameters of crystalline lens components and to find effective factors for predicting postoperative intraocular lens (IOL) position. This retrospective study included 97 eyes from 97 patients with a mean age of 63.00 ± 12.38 (SD) years. The biometric measurements were performed by means of a 3-dimensional optical coherence tomography (3D-OCT) device. Specifically, anterior chamber depth (ACD), aqueous depth (AD), lens thickness (LT), lens meridian parameter (LMP), white-to-white diameters (WTW), anterior segment length (ASL), the anterior part of lens (aLT), and the posterior part of lens (pLT) were measured. Additionally, axial length (AL) and corneal radius (CR) were measured by the partial coherence interferometry. Ninety-seven eyes were divided into thin lens group (LT < 4.5 mm) and thick lens group (LT ≥ 4.5 mm). The differences between the above two groups were also analyzed. Postoperative IOL position was measured by 3D-OCT at 3 months postoperatively and regression formulas for predicting postoperative IOL position were developed by various combinations of preoperative factors. As lens thickened, ACD and AD became shallow (all P < .001). AD, ACD, ASL, aLT, and pLT showed statistically significant differences between two subgroups classified on the basis of LT (all P < .001). Meanwhile, the value obtained by subtracting aLT from pLT did not show any association with the other biometric measurements. The combination of ACD, aLT, pLT, AL, CR, and WTW showed the highest correlation with postoperative IOL position (R = 0.536, P < .001). In conclusion, pLT-aLT was an independent factor not affected by any other variables and did not show significant difference between thin lens group and thick lens group. The subdivision of the lens structure using 3D-OCT helps to predict postoperative IOL position.

Correlations between ocular biometrics and refractive error: A systematic review and meta-analysis

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.

Evaluation of biometry and corneal astigmatism in cataract surgery patients in Northern United Arab Emirates

PURPOSE

To analyze biometric parameters and patterns of corneal astigmatism in cataract surgery patients using optical low-coherence interferometry in Northern United Arab Emirates (UAE).

METHODS

Axial length (AL), anterior chamber depth (ACD), horizontal corneal diameter (white to white, WTW) and flat and steep keratometry (K1 and K2, respectively) were optically measured using optical low-coherence interferometry (Aladdin). Ocular datasets acquired between 2015 and 2018 were collected and analyzed.

RESULTS

This study evaluated 238 eyes of 123 cataract patients with a mean age of 67.1 ± 9.4 years. Mean AL, ACD, WTW, K1, and K2 were 23.22 ± 0.99 mm, 3.05 ± 0.36 mm, 11.19 ± 0.46 mm, 43.72 ± 1.80 diopter (D), and 45.04 ± 1.71 D, respectively. Mean corneal astigmatism was 1.32 ± 0.97 D. Corneal astigmatism of 1.5 D or greater was found in 32.4%. With the rule, against the rule, and oblique astigmatism were found in 29.8%, 57.1%, and 13.0% of eyes, respectively.

CONCLUSIONS

Results of this study provide normative data for cataract surgery as an informative reference in Northern UAE, the Middle East. This study showed higher corneal astigmatism in Northern UAE than those in other countries.

Influence of corneal diameter on surgically induced astigmatism in small-incision cataract surgery

OBJECTIVE

Clear corneal incisions (CCI) in cataract surgery create a variable amount of surgically induced astigmatism (SIA). As refractive outcomes become increasingly important, it is necessary to understand factors that impact SIA and refractive surprises. In this study, we evaluate the effect of horizontal corneal diameter (white-to-white, WTW) on SIA in 2.2 mm small-incision cataract surgery.

DESIGN

Prospective study at an academic-university-based outpatient clinic (Duke Eye Center).

PARTICIPANTS

We enrolled adults ≥18 years of age without prior corneal surgery or corneal pathology undergoing cataract surgery with a single surgeon (R.R.V.).

METHODS

All surgeries were uncomplicated and performed through a manually constructed, limbal, temporal, or superotemporal 2.2 mm CCI. Enrolled participants received standard-of-care evaluations and postoperative management. SIA was calculated at the first postoperative month using the Jaffe and Clayman vector analysis equation.

RESULTS

We enrolled 43 subjects (55 eyes) with a mean age of 71 years with WTW corneal diameter values ranging from 11.34 to 12.99 mm obtained from Lenstar^® (Haag-Streit Group, Koeniz, Switzerland). Postoperative SIA ranged from 0.072 to 1.6 D (mean 0.47 D, standard deviation 0.33 D). SIA was plotted against WTW and best fit to a linear regression model with a slope of -0.056 and an R² value of 0.006.

CONCLUSIONS

In this prospective study, WTW diameter had minimal effects on the SIA in uncomplicated small-incisional cataract surgery through a 2.2 mm temporal or superotemporal CCI with a single surgeon. Our findings suggest that corneal diameter does not play a clinically significant role in this population undergoing small-incisional cataract surgery.

Corneal astigmatism in cataract surgery patients from Bosnia and Herzegovina

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.

Effect of incision on visual outcomes after implantation of a trifocal diffractive IOL

Background

To evaluate visual acuity, corneal astigmatism and corneal higher-order aberrations (HOAs) after implantation of trifocal diffractive IOLs operated with either a corneal steep-axis incision or 135° incision.

Method

This prospective study enrolled patients randomly assigned to different groups. According to preoperative corneal astigmatism, 101 eyes of 77 patients were assigned into group A₁ (0 ~ 0.50 D) or A₂ (0.51 ~ 1.00 D) with a corneal steep-axis incision or group B₁ (0 ~ 0.50 D) or B₂ (0.51 ~ 1.00 D) with a 135° incision. Visual acuity, corneal astigmatism and corneal higher-order aberrations (HOAs) were followed-up for 3 months.

Results

Corneal astigmatism in group A₂ significantly decreased 3 months after surgery (P < 0.01) and was significantly lower than that in group B₂ 1 day, 2 weeks, 1 month, and 3 months postoperatively (all values of P < 0.01). The following parameters were better in group A₂ than in group B₂: uncorrected intermediate visual acuity (UIVA) at 1 day, 2 weeks, 1 month, and 3 months (P = 0.00, 0.00, 0.01, 0.01, respectively);uncorrected distance visual acuity (UDVA) at 1 day and 2 weeks (P = 0.00, 0.01); and uncorrected near visual acuity (UNVA) at 1 day, 2 weeks, and 1 month postoperatively (P = 0.00, 0.01, 0.02, respectively).

Conclusions

After a corneal steep-axis incision, patients with preoperative corneal astigmatism of 0.51 D to 1.00 D exhibited reduced corneal astigmatism and achieved better UIVA and early postoperative UDVA/UNVA.

Trial registration

Retrospectively Registered Trials ISRCTN10086721, 23/06/2018.

Assessment of Corneal Keratometric and Astigmatism Measurements Using Verion System and Other Instruments in Cataract Patient

PURPOSE

To compare keratometry and corneal astigmatism measurements obtained by the Verion Image Guided System to those obtained by automated keratometry (IOLMaster), manual keratometry (YZ38, Suzhou 66 visual Polytron Technologies Inc., China), and Scheimpflug imaging (Pentacam HR) in eyes with cataract.

METHODS

A total of 149 cataractous eyes of 149 patients were examined and categorized as low astigmatism (<1.0 D, N = 50), moderate astigmatism (1.0-2.0 D, N = 49), and high astigmatism (>2.0 D, N = 50). The flattest and the steepest keratometric values (Kf and Ks), the magnitude of astigmatism (Ast), the orientation of the steepest meridian (Axis), and power vectors J₀ and J₄₅ were compared.

RESULTS

Keratometry readings (Kf, Ks, and Km) obtained by the Verion system showed statistically significant differences as compared to the other three devices. The magnitude of astigmatism (Ast) measured by the Verion (1.50 ± 0.85 D) was similar to that measured by the YZ38 (1.45 ± 0.82 D, P = 0.110) and slightly lower than that by the IOLMaster (1.56 ± 0.87 D, P = 0.014), but much higher than that by the Pentacam (1.36 ± 0.81 D, P = 0.000) significantly. However, no statistically significant differences were observed in the J₀ and J₄₅ vectors in the whole sample, besides moderate and high astigmatism subgroups. A difference in astigmatism magnitude of 0.50 D or more was detected between the Verion system and other three devices most commonly in moderate astigmatism eyes (16.3-24.5%). The difference in the location of the steep meridian was greater than 10 degrees most frequently in the low astigmatism eyes (26.0-52.0%).

CONCLUSIONS

Keratometric and astigmatic results obtained with Verion were not completely interchangeable with those obtained with IOLMaster, manual keratometry, and Pentacam. The individual differences in power and orientation of the corneal cylinder should be considered while selecting the appropriate toric intraocular lens.

Ocular biometric characteristics of cataract patients in western China

BACKGROUND

We aimed to measure ocular biometric characteristics in older cataract patients from western China.

METHODS

Ocular biometry records were retrospectively analyzed for 6933 patients with cataracts (6933 eyes) at least 50 years old who were treated at West China Hospital of Sichuan University.

RESULTS

Partial coherence laser interferometry gave the following population averages: axial length (AL), 24.32 ± 2.42 mm; anterior chamber depth (ACD), 3.08 ± 0.47 mm; keratometric power (K), 44.23 ± 1.66 diopters; and corneal astigmatism (CA), 1.00 ± 0.92 diopters. The percentage of individuals with AL > 26.5 mm was 13.66%, while the percentage with CA > 1.0 diopters was 35.54%. Mean AL and ACD showed a trend of decrease with increasing age (P < 0.001). AL correlated positively with ACD (Spearman coefficient, 0.542) and CA (0.111), but negatively with K (- 0.411) (all P < 0.01). K also correlated negatively with ACD (- 0.078, P < 0.01).

CONCLUSIONS

These results show, for the first time, that older cataract patients from western China have similar ocular biometric characteristics as other populations. The high prevalence of severe axial myopia warrants further investigation.

Global prevalence and economic and humanistic burden of astigmatism in cataract patients: a systematic literature review

Purpose

To systematically review the published evidence on the prevalence and economic and humanistic burden of astigmatism in cataract patients.

Materials and methods

For this systematic literature review, the Medline, PubMed, Embase, and Cochrane databases were searched from 1996 to September 2015 for available scientific literature that met the inclusion criteria. Studies published in the English language reporting prevalence and humanistic and economic burden in patients diagnosed with cataract and astigmatism were included.

Results

Of 3,649 papers reviewed, 31 studies from 32 publications met the inclusion criteria of this review. Preexisting astigmatism ≥1 D was present in up to 47% of cataract eyes. The cost burden of residual uncorrected astigmatism after cataract surgery was driven by the cost of spectacles, which was estimated to range from $2,151 to $3,440 in the US and $1,786 to $4,629 in Europe over a lifetime. In cataract patients, both preexisting and postoperative residual astigmatism were associated with poor vision-related patient satisfaction and quality of life, as well as higher spectacle burden. Astigmatism correction during cataract surgery appears to improve visual outcomes and results in overall lifetime cost savings compared to astigmatism correction with postoperative vision correction.

Conclusion

There is a high prevalence of preexisting astigmatism in cataract patients. Although published data are limited, both preoperative astigmatism and postoperative residual astigmatism affect visual function and vision-related quality of life, resulting in increased humanistic burden. Suboptimal correction of astigmatism during cataract surgery drives the continuous need for vision correction with spectacles in the postoperative period. Patients must bear the out-of-pocket expenses, since payers often do not reimburse the cost of spectacles. Greater access to astigmatism correction during cataract surgery could improve visual outcomes and quality of life in patients. More research is required to gain a better understanding of the disease burden of astigmatism in cataract patients.

[Prevalence and age-related changes of corneal astigmatism in patients before cataract surgery]

BACKGROUND

The aim of this study was to determine the extent and the distribution of corneal astigmatism in patients awaiting cataract surgery in a mid-European tertiary clinic centre and hence to establish the demand for methods reducing corneal astigmatism.

PATIENTS AND METHODS

Keratometry measurements of cataract surgery candidates assigned to a university clinic between January 2013 and October 2014 were recorded and analysed retrospectively.

RESULTS

A total of 6900 eyes of 3450 patients with a mean age of 72.5 ± 12.2 were analyzed. The corneal astigmatism was more than 0.5 dioptres (D) in 5193 eyes (75.3 %), >1.0 D in 2641 eyes (38.3 %), >1.5 D in 1304 eyes (18.9 %), >2.0 D in 644 eyes (9.3 %), >2.5 D in 363 eyes (5.3 %), >3.0 D in 236 eyes (3.4 %) and >3.5 D in 149 eyes (2.2 %). With increasing age a shift from with-the-rule astigmatism towards against-the-rule astigmatism was observed.

CONCLUSION

Of the patients admitted for routine cataract surgery at our clinic, 2641 eyes (38.3 %) had an astigmatism greater than 1.0 D. Our data could be helpful in establishing a protocol for using toric intraocular lenses and to determine the costs.

Evaluation of biometry and corneal astigmatism in cataract surgery patients from Central China

Background

To evaluate the distribution of biometric parameters and corneal astigmatism using the IOLMaster device before phacoemulsification in cataract patients in Central China.

Methods

Consecutive cataract patients were recruited at the Central Hospital of Wuhan between January 2015 and June 2016. Ocular axial length (AL), keratometry values, anterior chamber depth (ACD) and horizontal corneal diameter (white to white [WTW]) of each cataract-affected eye were measured with the IOLMaster device.

Results

The study evaluated 3209 eyes of 2821 cataract patients. The mean AL, ACD, and WTW were 24.38 ± 2.47 mm, 3.15 ± 0.48 mm, and 11.63 ± 0.43 mm, respectively. Corneal astigmatism of 0.51–1.00 diopters (D) was the most common range of values (34.96%). A total of 10.56% patients exhibited a corneal astigmatism greater than 2.0 D. The flat and steep keratometry values gradually increased with age. The mean ACD and WTW showed increasing trends as the AL increased (P < 0.001). When the AL was shorter than 26.0 mm, the keratometry decreased as AL increased. The against-the-rule (ATR) astigmatism proportion increased with age and the with-the-rule (WTR) astigmatism proportion decreased with age.

Conclusions

The profile of ocular biometric data and corneal astigmatism may help ophthalmologists improve their surgical procedures and make an appropriate IOL choice to gain a high quality of postoperative vision.

Determinants of anterior chamber depth in a large Caucasian population and agreement between intra-ocular lens Master and Pentacam measurements of this variable

PURPOSE

To establish the main determinants of anterior chamber depth (ACD) in Caucasian subjects and examine agreement between IOL Master(®) (Carl Zeiss, Meditec) and Pentacam(®) (Oculus Inc.) ACD measurements.

METHODS

In a cross-sectional study, 1006 right eyes of 1006 healthy subjects were subjected to a general ophthalmologic examination using the Pentacam(®) , IOLMaster(®) and OCT RTVue(®) (Optovue Inc.). The variables recorded were age, sex, intra-ocular pressure, spherical refractive error, axial length (AL), central corneal thickness, corneal diameter, iris thickness, and anterior chamber depth, volume and angle (ACA). The effects of these variables on ACD were analysed by multivariate linear regression.

RESULTS

Mean age was 49.1 years (range 18-84); 61% were women. In 98.3% of the eyes, ACD could be measured using the IOL Master and in 98% the Pentacam was used to give mean depths of 3.30 ± 0.42 mm and 3.35 ± 0.43 mm, respectively, for the two instruments. Agreement between these devices was high. In men, ACD was 0.13 mm on average deeper than in women (p < 0.001). ACD was correlated with ACA, AL, corneal diameter, spherical refractive error and age (p < 0.001). Five variables - age, sex, spherical error, corneal diameter and ACA - were able to explain 74.1% of the variation produced in ACD (R(2) = 0.741; p < 0.001), among which age emerged as the main determinant (partial R(2) = 0.279; p < 0.001).

CONCLUSIONS

Age, sex, spherical error, corneal diameter and ACA correlate highly with ACD and together serve to explain much of its variation. When used to measure ACD, the IOLMaster and Pentacam show excellent agreement.