Ocular biometric characteristics of cataract patients in western China

Ocular biometric characteristics of Han ethnicity in Tianjin and Uyghur ethnicity in Xinjiang undergoing cataract surgery

AIM

To analyze and compare the differences among ocular biometric parameters in Han and Uyghur populations undergoing cataract surgery.

METHODS

In this hospital-based prospective study, 410 patients undergoing cataract surgery (226 Han patients in Tianjin and 184 Uyghur patients in Xinjiang) were enrolled. The differences in axial length (AL), anterior chamber depth (ACD), keratometry [steep K (Ks) and flat K (Kf)], and corneal astigmatism (CA) measured using IOL Master 700 were compared between Han and Uyghur patients.

RESULTS

The average age of Han patients was higher than that of Uyghur patients (70.22±8.54 vs 63.04±9.56y, P<0.001). After adjusting for age factors, Han patients had longer AL (23.51±1.05 vs 22.86±0.92 mm, P<0.001), deeper ACD (3.06±0.44 vs 2.97±0.37 mm, P=0.001), greater Kf (43.95±1.40 vs 43.42±1.69 D, P=0.001), steeper Ks (45.00±1.47 vs 44.26±1.71 D, P=0.001), and higher CA (1.04±0.68 vs 0.79±0.65, P=0.025) than Uyghur patients. Intra-ethnic male patients had longer AL, deeper ACD, and lower keratometry than female patients; however, CA between the sexes was almost similar. In the correlation analysis, we observed a positive correlation between AL and ACD in patients of both ethnicities (rHan =0.48, rUyghur =0.44, P<0.001), while AL was negatively correlated with Kf (rHan =-0.42, rUyghur =-0.64, P<0.001) and Ks (rHan =-0.38, rUyghur =-0.66, P<0.001). Additionally, Kf was positively correlated with Ks (rHan =0.89, rUyghur =0.93, P<0.001).

CONCLUSION

There are differences in ocular biometric parameters between individuals of Han ethnicity in Tianjin and those of Uyghur ethnicity in Xinjiang undergoing cataract surgery. These ethnic variances can enhance our understanding of ocular diseases related to these parameters and provide guidance for surgical procedures.

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.

Imaging analysis of the biological parameters of the lens in patients with cortical age-related cataracts using ultrasound biomicroscopy

BACKGROUND

The spatial position of the lens in patients with cortical age-related cataract (CARC) is unclear. We investigated a basis for the assessment of visual quality after cataract surgery by analysing the ultrasound biomicroscopic characteristics of the biological parameters of the lens in patients with CARC.

METHODS

In this retrospective study, 119 patients (50 males and 69 females, totalling 238 eyes) with CARC who underwent simple cataract surgery were selected. The lens thickness (LT), axial length (AL), anterior chamber depth (ACD), lens vault (LV), trabecular-iris angle (TIA), iris-lens angle (ILA), iris-lens contact distance (ILCD) were measured by A-scan ultrasound and ultrasound biomicroscopy. The corresponding lens position (LP) and relative lens position (RLP) were calculated.

RESULTS

LP was greater in men than in women (P < 0.05), LV was smaller in men than in women (P = 0.002), ILA and ILCD were not statistically significant (P = 0.072 and P = 0.854, respectively). There were significant differences in TIA, ILA, and ILCD in the four quadrants (all P < 0.05), with a trend in the distribution of TIA: superior < inferior < nasal < temporal, ILA: nasal < inferior < temporal < superior, and ILCD: superior < temporal < inferior < nasal.

CONCLUSIONS

The lens protrudes more obviously in females than in males and the lens tilts to a certain extent with the increase of age and tends to be more upward and temporal in the supine position. Therefore, trends in lens-related parameters in patients with CARC should be taken seriously.

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.

Axial length and anterior chamber indices in elderly population: Tehran Geriatric Eye Study

AIM

To determine the normative distribution of axial length (AL), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and some of their associated factors in subjects aged 60 and over.

METHODS

In this cross-sectional study, 160 clusters were sampled using multi-stage cluster sampling in Tehran, Iran. After a preliminary interview, the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy. Finally, ocular imaging was done using the Pentacam AXL to measure AL, ACD, ACV, and ACA.

RESULTS

A total of 4519 eyes of 2436 participants were evaluated, of whom 58.0% (n=1412) were female. The mean age of the subjects was 67.32±6.05y (range: 60-95y). The mean AL, ACD, ACV, and ACA was 23.22 mm (23.18-23.27 mm), 2.61 mm (2.59-2.62 mm), 126.56 mm3 (125.08-128.04 mm3), and 30.61° (30.3°-30.92°), respectively. In the multivariable model, after adjusting for the effect of both eyes, the longest and shortest AL was seen in myopic and hyperopic subjects, respectively. AL, ACD, ACV and ACA were significantly larger in men compared to women (P<0.001). Except ACA, other evaluated parameters showed an inverse correlation with age (P<0.001), however, this correlation was insignificant for AL (P=0.623).

CONCLUSION

Normative value of AL, and other biometric parameters are specific for each ethnicity, age and sex group. Any alteration in these parameters and their effect on refraction should be considered in this age group, especially in case of cataract surgery.

Binocular Visual Outcomes Comparison of Two Trifocal Intraocular Lenses in High-Myopic Cataract Patients: A 1-Year Multicenter Study

PURPOSE

To compare the postoperative visual outcomes and quality of vision obtained with 2 types of diffractive trifocal intraocular lenses (IOLs) in patients with highly myopic cataracts.

DESIGN

Prospective, multicenter, randomized controlled trial.

METHODS

Patients with high-myopic cataracts were randomized to binocular implantation of either the TFNT00 (n = 27) or the 839 MP (n = 28) trifocal IOLs at 3 surgery centers in China and were followed up for 1 year. Postoperative uncorrected distance, uncorrected intermediate, and uncorrected near visual acuity, and best-corrected distance visual acuity were measured. The defocus curve, high-order aberrations, modulation transfer function curve, Strehl ratio, and reading ability were compared between both groups. The functional vision and incidence of photic phenomena were surveyed using questionnaires.

RESULTS

Visual acuity at all ranges of vision was significantly improved in both groups. The TFNT00 group showed superior uncorrected intermediate visual acuity to that in the 839 MP group (P = .013). Reading ability at 40 and 60 cm was similar in both groups (P ≥ .05), whereas the preferred reading distances for near and intermediate were significantly different. The TFNT00 group had a significantly higher mean Visual Function Index 14 score, lower incidence of photic phenomena, and less posterior capsular opacity than the 839 MP group.

CONCLUSION

Bilateral implantation of both types of trifocal IOLs in patients with high-myopic cataracts provided good whole-course visual restoration, although recognition of fine Chinese characters remained impeded. As compared with 839 MP IOL, TFNT00 IOL resulted in greater patient satisfaction in intermediate activities, with a lower photic phenomena incidence.

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.

[Reasonability of accounting for gender in intraocular lens power calculation]

PURPOSE

The study assesses the influence of gender on the accuracy of intraocular lens (IOL) power calculation by formulas SRK/T, Barrett Universal II (BUII), Ladas super formula (LSF), Hill RBF (RBF) and Kane.

MATERIAL AND METHODS

The study enrolled 214 patients (106 men and 108 women) who underwent cataract phacoemulsification (PE). Optical biometry was performed on IOL-Master 500. IOL power calculation was performed either adjusting for gender (formulas SRK/T, BUII, LSF) or without such adjustment (formulas RBF, Kane). Calculation error (CE) was assessed one month after PE by comparing the achieved (autorefractometer Topcon-8800) and target spherical equivalent of refraction.

RESULTS

Significant differences were found in mean IOL CE with gender-unspecific formulas (SRK/T, BUII, LSF) and no differences in gender-specific calculators (RBF, Kane). The Kane formula demonstrated the lowest CE between men and women (-0.01±0.43 versus -0.09±0.41 D; p=0.158), while the SRK/T formula had the highest CE (0.02±0.46 versus -0.21±0.44 D, respectively; p<0.001). Presence of a significant correlation between CE and gender was found for all formulas except Kane (R2=0.005, p=0.158).

CONCLUSION

Patient's gender has a significant impact on IOL calculation accuracy. Using gender-responsive formulas could help achieve better refractive results with PE. The present study showed Kane formula to have the least CE dependence from gender. However, the CE difference (less than 0.25 D) was lower than the value of division (0.5D) in modern IOL models.

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.

Measured Corneal Astigmatism Versus Pseudophakic Predicted Refractive Astigmatism in Cataract Surgery Candidates

PURPOSE

To compare standard and total corneal astigmatism measurements to the predicted pseudophakic (nontoric) refractive astigmatism in candidates for cataract surgery.

DESIGN

A retrospective, cross-sectional study.

METHODS

A single-center analysis of consecutive eyes measured with a swept-source optical coherence tomography biometer at a large tertiary medical center between February 2018 and June 2020. Corneal astigmatism was calculated based on standard keratometry astigmatism (KA), total corneal astigmatism (TCA), and predicted refractive astigmatism (PRA) for a monofocal nontoric intraocular lens (IOL) implantation calculated by the Barrett toric calculator using the predicted posterior corneal astigmatism (PRA_{(Predicted-PCA)}) and the measured posterior corneal astigmatism (PRA_{(Measured-PCA)}) options. Separate analyses were performed for each eye.

SETTING

Ophthalmology Department, Shaare Zedek Medical Center, Jerusalem, Israel.

RESULTS

In total, 8152 eyes of 5320 patients (4221 right eyes [OD] and 3931 left eyes [OS], mean age 70.6±12.2 years, 54.2% females) were included in the study. The mean vector values (centroid) for KA, TCA, PRA_{(Predicted-PCA)}, and PRA_{(Measured-PCA)} were 0.07 diopters [D] at 19.5°, 0.27 D at 7.5°, 0.44 D at 2.9°, and 0.43 D at 179.3°, respectively (P < .01), for OD and 0.02 D at 150.3°, 0.23 D at 169.7°, 0.40 D at 179.4°, and 0.42 D at 169.5°, respectively (P < .01), for OS. More than 73% of eyes had a PRA >0.5 D.

CONCLUSIONS

Standard and total corneal astigmatism measurements differ significantly from the PRA by the Barrett toric calculator. The PRA, rather than the KA or TCA, should be used as the reference guide for astigmatism correction with toric IOL implantation.

Ocular Biometric Characteristics Measured by Swept-Source Optical Coherence Tomography in Individuals Undergoing Cataract Surgery

PURPOSE

To study the distribution of ocular biometric parameters using a swept-source optical coherence tomography (SS-OCT) biometer in adult candidates for cataract surgery.

DESIGN

A retrospective cross-sectional study.

METHODS

This is a single-center analysis of consecutive eyes measured with the IOLMaster 700 SS-OCT biometer at a large tertiary medical center between February 2018 and June 2020.

RESULTS

Three thousand eight hundred thirty-six eyes of 3836 patients were included in the study. The mean ± SD age was 72.3 ± 12.8 years and 53% were female. The mean biometric values were as follows: total corneal power (44.17 ± 1.70 diopters [D]), total corneal astigmatism (TCA; 1.11 ± 0.87 D), mean posterior keratometry (-5.87 ± 0.26 D), posterior corneal astigmatism (-0.26 ± 0.15 D), axial length (AL; 23.95 ± 1.66 mm), anterior chamber depth (ACD; 3.18 ± 0.42 mm), lens thickness (LT; 4.49 ± 0.47 mm), white-to-white distance (WTW; 11.92 ± 0.44 mm), central corneal thickness (CCT; 0.54 ± 0.04 mm), angle alpha (0.49 ± 0.17 mm), and angle kappa (0.34 ± 0.17 mm). There were sex-related differences in all biometric parameters save for LT (P = .440), angle kappa (P = .216), and corneal astigmatism (P = .103). Biometric parameters demonstrated correlations between AL, WTW distance, ACD, and LT (P < .001). Age correlated with all parameters (P < .001) except CCT and posterior keratometry. Angle alpha and angle kappa magnitudes also correlated (P < .001). The prevalence of patients with TCA ≥0.75 D, 1.0 D, and 1.5 D were 59.1%, 43.4%, and 22.6%, respectively.

CONCLUSIONS

Age significantly correlated with most of the biometric parameters and significant differences between sexes were noted. In addition, the high prevalence of TCA and relatively large angle alpha and angle kappa magnitudes were noted among subjects. These data can be relevant in planning local and national health economics.

Birth Year-Dependent Increase in Axial Length of Japanese Adult

PURPOSE

To determine whether the correlations between the axial length and the aging-dependent and birth year-dependent age are significant.

DESIGN

Retrospective cross-sectional study.

METHODS

This study included Japanese patients ≥50 years who had undergone cataract surgery at numerous clinics from 2002 to 2020. Only 1 eye/patient was analyzed. The axial length was measured with the IOL Master. The age-dependent changes were determined by the significance of the correlation between the axial length and age by the birth year. The birth year-dependent changes were determined by the significance of the correlation between the axial length and birth year in the different age groups. The age refers to the age at the time of the cataract surgery. Spearman correlations were calculated. The turning points were identified by the LOESS, NLIN, and HPMIXED procedures.

RESULTS

A total of 62,362 eyes (35,508 women, 26,854 men) were studied. The mean age was 72.9 ± 8.4 (standard deviation) years (range, 50-101 years), and the mean axial length was 23.90 ± 1.66 mm (standard deviation) (range, 19.20-37.07 mm). The birth year ranged from 1908 to 1970. Analyses of the birth year-dependent changes showed significant positive correlations in 48 of 81 (59.3%) groups for women and men. The increase in the axial length was birth year-dependent, and the turning point was 1939.4 for women and 1936.7 for men.

CONCLUSIONS

The negative and significant correlation between the axial length and age is due to birth year-dependent changes. A birth year-dependent increase in axial length might have continued for several decades from the birth year of the late 1930s.

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.

Changes in ocular morphology after cataract surgery in open angle glaucoma patients

The purpose of this study was to evaluate intraocular pressure (IOP) pre- and postoperatively, together with anterior chamber angle (ACA) parameters and biometrical results in cataract patients with or without open angle glaucoma (OAG). The prospective observational case-control study included 15 eyes with cataract and OAG in the glaucoma group and 25 eyes with only cataract in control group. Examination included full ophthalmic evaluation, IOP, ocular biometry and anterior segment optical coherence tomography measuring ACA pre- and 6 months postoperatively. OAG patients had a larger absolute IOP reduction compared to control group. Anterior chamber depth (ACD) and ACA width significantly increased in both groups. The OAG group had a tendency of narrower ACA preoperatively, but overall ACA parameters did not differ in either group pre- and postoperatively. The ACD change after surgery correlated with ACA parameters in the control group, but not in OAG group. Axial length was shorter postoperatively in the control group, but remained similar in the OAG group. Absolute IOP reduction was more pronounced in cataract patients with OAG than in cataract patients without glaucoma. ACD and ACA postoperatively increased in both groups and AL shortening was observed in non-OAG in cataract group.

Ocular biometry characteristics in cataract surgery candidates: a cross-sectional study

Background

This study was conducted to investigate ocular biometry parameters in cataract surgery candidates in northern Tehran, Iran using OA-2000 biometry device.

Methods

In this cross-sectional study, values of ocular biometry parameters, including axial length (AL), anterior chamber depth (ACD), mean corneal curvature (mean K), lens thickness (LT), corneal astigmatism (CA), and white-to-white (WTW) of 818 eyes with cataracts, were measured using the OA-2000 biometry device (Tomey, Nagoya, Japan). The participants were divided into si age subgroups, in 10-year intervals. Finally, the values of the biometry parameters were calculated, and the trend of changes was examined for both age and sex subgroups.

Results

The mean (standard deviation [SD]) of age of the participants was 63.82 (13.25) years. Mean (SD) of biometry parameters were as follows: AL, 23.36 (1.55) mm; ACD, 3.09 (0.40) mm; LT, 4.45 (0.55) mm; mean K, 44.51 (1.72) D; CA, 1.06 (0.94) D; and WTW, 11.81 (0.45) mm. Most of the parameters showed significant age-related changes in the total population. There was an increase in LT (P < 0.001) and mean K (P = 0.001), as well as a decrease in AL (P < 0.001) and ACD (P < 0.001) with age. Moreover, AL had a negative negligible correlation with LT (r = - 0.24; P < 0.001) and mean K (r = - 026; P < 0.001), as well as a weak positive correlation with ACD (r = + 0.44; P < 0.001).

Conclusions

Our study revealed that the mean values of most biometric parameters varied across age and sex subgroups. Moreover, most of the parameters showed significant age-related changes in the total population.

Biometry, Refractive Errors, and the Results of Cataract Surgery: A Large Sample Study

The statistical characteristics of biometry and refractive error in a large sample of cataractous Cuban patients are presented, comparing between sexes and age groups. All patients were studied at the Cuban Institute of Ophthalmology “Ramón Pando Ferrer,” La Habana. The sample consists of 28252 eyes of 25068 patients, subjected to cataract surgery during the time period between 2006 and 2019. Their biometry was obtained using IOL Master devices; also, visual acuity, refraction, and corneal power were registered. After surgery, the visual acuity and refraction were measured. The refractive prediction error was determined. For patients with both eyes registered, anisometropia was also calculated. Age and sex were used to segment the data. The preoperative biometric parameters show highly significant differences between sexes, with male eyes being longer and with a deeper anterior chamber but with a thinner lens. Also, keratometry shows highly significant differences, with female eyes being steeper than male. Before surgery, both sexes have myopic eyes as average, with males being more myopic than females (p < 0.001). After surgery, the average spherical equivalent is −0.36 D and female eyes are more myopic than males (p < 0.001). Visual acuity with and without distance correction has a significant increase after surgery. These results are of importance not only for Cuba but also for other countries with a large Cuban population and/or similar ethnic composition, such as the USA (particularly the south of Florida), Spain, and many countries in Latin America.

Gender differences in refraction prediction error of five formulas for cataract surgery

Objectives

To evaluate gender differences in optical biometry measurements and lens power calculations.

Methods

Eight thousand four hundred thirty-one eyes of five thousand five hundred nineteen patients who underwent cataract surgery at University of Michigan’s Kellogg Eye Center were included in this retrospective study. Data including age, gender, optical biometry, postoperative refraction, implanted intraocular lens (IOL) power, and IOL formula refraction predictions were gathered and/or calculated utilizing the Sight Outcomes Research Collaborative (SOURCE) database and analyzed.

Results

There was a statistical difference between every optical biometry measure between genders. Despite lens constant optimization, mean signed prediction errors (SPEs) of modern IOL formulas differed significantly between genders, with predictions skewed more hyperopic for males and myopic for females for all 5 of the modern IOL formulas tested. Optimization of lens constants by gender significantly decreased prediction error for 2 of the 5 modern IOL formulas tested.

Conclusions

Gender was found to be an independent predictor of refraction prediction error for all 5 formulas studied. Optimization of lens constants by gender can decrease refraction prediction error for certain modern IOL formulas.

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.

Visual quality after implantation of trifocal intraocular lenses in highly myopic eyes with different axial lengths

AIM

To analyze postoperative clinical results after implantation of trifocal intraocular lenses (IOLs) in highly myopic eyes with different axial lengths (ALs).

METHODS

This retrospective study describes 61 eyes of 44 patients that were implanted with trifocal diffractive IOLs (AT LISA tri 839MP). Twenty-one eyes (15 patients) were included in the AL<26 mm group, 19 eyes (13 patients) in the AL≥26 mm and <28 mm group, and 21 eyes (16 patients) in the AL≥28 mm group. Postoperative outcomes, including corrected and uncorrected distance visual acuity (UDVA), intermediate and near visual acuity at 167 cd/m² luminance, depth of focus at 85 cd/m² luminance, and objective optical quality parameters assessed using the Optical Quality Analysis System (OQAS), were compared among the groups at 3mo.

RESULTS

There were no significant differences in the mean UDVA, uncorrected intermediate visual acuity, uncorrected near visual acuity, corrected distance visual acuity, distance-corrected intermediate visual acuity, and distance-corrected near visual acuity (DCNVA) among the three groups (P>0.05). Better near and intermediate visual acuity (from -1.5 D to -3.0 D) were noted on the defocus curve of the AL<26 mm group (P<0.01 vs AL≥28 mm group). Significantly higher objective scatter index (OSI) values and lower modulation transfer function (MTF) cut-off values, Strehl ratio (SR), and OQAS values (OVs) were observed in the AL≥28 mm group (P<0.01 vs AL<26 mm group). All OQAS parameters had statistically significant correlations with DCNVA and visual acuity at the vergence of -2.5 D (P<0.05 to P<0.01).

CONCLUSION

Implantation of trifocal IOLs provides good short-term visual and refractive outcomes in highly myopic eyes with different ALs. However, the near vision decreases in the extremely myopic eyes at lower luminance, which is associated with the lower objective optical quality in these 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.

[Intraocular lens power in Russian population: distribution analysis]

Approximately 470 thousand cases of cataract surgery with implantation of intraocular lens (IOL) are performed annually in Russia. The distribution of IOL power in the Russian population has not been studied sufficiently, which makes the IOL procurement planning imperfect.

PURPOSE

To analyze the distribution of implanted IOL power and optimize the IOL procurement system.

MATERIAL AND METHODS

Retrospective analysis of cataract surgeries performed from 2014 to 2015 in the ophthalmic department of Volga District Medical Centre of the FMBA was conducted. Inclusion criteria: age from 20 to 99 years, no refractive surgery in patient's medical history, primary IOL implantation with an A-constant of 118.4, achievement of planned refraction. The studied parameters were IOL power, gender and age of patients. To assess the effectiveness of the procurement system, we analyzed the number of additional «unplanned» purchases and exchanges of IOLs over the course of 5 years (2014-2018).

RESULTS

According to the inclusion criteria, 1009 medical records were selected, the age of the patients was 68.7±10.9 years. The distribution of IOL power was similar, but different from the normal, characterized by the mismatch of the median and the mean, left-sided asymmetry and peaked shape. Comparison of 2014 and 2015 samples showed no significant differences and low variability of IOL power. Regression analysis revealed a weak correlation between the IOL power and age and no correlation with gender, a trend was observed for IOL power to increase in patients after 50 years. The use of a procurement planning system based on a mathematical model of the IOL power distribution allows reduction of the additional purchases and exchanges of IOLs with the supplier from 5-7% to 1-2% of the total purchases.

CONCLUSION

The specific features of the IOL power distribution are related to the distribution of biometry parameters in the population. The use of a scientifically based procurement system reduces staff time and laboring costs, releasing economical and time resources.

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.