Gender and age-related differences of ccular biometric parameters in patients undergoing cataract surgery in Bosnia and Herzegovina

Purpose: 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±1.18mm, 3.17±0.40mm, 4.54±0.48mm, 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.

Methods
This was a retrospective cross-sectional study of the eyes of 1278 consecutive patients who underwent cataract surgery in a private tertiary care clinic in Bosnia and Herzegovina, between January 1, 2017, and December 31, 2021. All included patients were citizens of Bosnia and Herzegovina and belong to different ethnic groups. However, there is no major genetic difference between three major ethnic groups in Bosnia and Herzegovina, (Bosniaks, Bosnian Serbs, and Bosnian Croats), indicating that they present the same gene pool. Furthermore, the human population of Bosnia and Herzegovina is closely related to other populations in the Balkans. In patients who underwent surgery on both eyes, we used data for the right eye only. The current study was approved by the institution’s Ethics Committee (Approval number: 01-1-2022). Informed consent was obtained from all patients included in the study at the time of cataract surgery, and the study was conducted according to the Declarations of Helsinki.

All biometric measurements were performed using the optical biometer OA-2000 (Tomey, Nagoya, Japan). For measurements of axial length (AL), anterior chamber depth (ACD) and lens thickness (LT), it uses swept-source optical coherence tomography (SS-OCT) with a laser wavelength of 1060 nm. It is capable of simultaneously measuring corneal curvature by Placido-disc–based topography techniques with 9 rings each 256 points in a 5.5 mm zone projected onto the cornea. For measurement, all subjects were asked to sit in front of the instrument, place their chin in the chinrest, focus on a target, blink completely and keep their eyes wide open without blinking during scanning. The device performs the measurements automatically without the need for realignment.

Corneal astigmatism was designated as against-the-rule (ATR) when the axis of correcting minus cylinder was within 30° of the vertical 90° meridian, with-the-rule (WTR) when the correcting minus cylinder axis was within 30° of the horizontal 180° meridian, and oblique (OBQ) if it was neither ATR nor WTR orientation. Based on AL all eyes were stratified into 3 groups: shorter than 22.0mm, 22–24.5mm, and longer than 24.5mm. Age was stratified into 5 groups: 40–49, 50–59, 60–69, 70–79, and ≥ 80 years of age.

After biometry, all patients underwent a complete ophthalmic examination, including visual acuity testing with Snellen charts, tonometry, detailed slit lamp biomicroscopy, pupillary reaction, and fundoscopy. The inclusion criteria for the current study were the presence of cataract and the age of 40 years or older. The exclusion criteria were dense cataracts that interfered with biometric measurement, ocular surface disorders, previous corneal or intraocular surgery, and a history of intraocular inflammation and penetrating eye trauma.

Continuous variables were tested for normality using the Shapiro-Wilk test and presented as mean and standard deviation (SD) or, if strongly skewed, additionally as medians and interquartile range (IQR). Differences between continuous variables among different groups were tested using the t-test if normally distributed, while the non-parametric Wilcoxon Mann-Whitney test was used for non-normally distributed variables. Binary and categorical variables are reported as absolute numbers and percentages and are tested for differences using the chi-square test. A rank-based nonparametric Kruskal-Wallis test was applied to determine differences between more than two groups of an independent variable in continuous dependent variables. The correlation was estimated using the pairwise Pearson correlation coefficient. All analyses were performed with Stata version 15.1 (StataCorp, College Station, Texas, USA). The significance level for hypothesis testing was set at 0.05.