Ocular Biometry Among Cataract Surgery Candidate Patients In Southwestern Ethiopia

Abstract

Abstract Background: Cataract surgery is the most commonly performed surgical procedure in the world. The precision of biometry is crucial for meeting the expectations of patients undergoing cataract surgery. To meet these expectations, attention to accurate biometry measurements is critical. Ocular biometric parameters such as axial length (AL), corneal power (K), and anterior chamber depth (ACD) vary with gender, age, and ethnicity, and hence are different among different populations. This study aimed to determine the means and ranges for axial length, anterior chamber depth, corneal power values, and pattern of astigmatism and cataract surgery candidate patients of Southwestern Ethiopia. Methods: A hospital-based, prospective cross-sectional study was conducted on all adult patient candidates for cataract surgery in Jimma Medical Centre Ophthalmology clinic. Each participant underwent non-cycloplegic autorefraction and a full ophthalmic examination including slit-lamp biomicroscopy, intraocular pressure measurement, and fundus examination (if visible). The corneal curvature (K), AL, and ACD were measured using IOLMaster (Carly Zeiss Meditech AG Jene, Germany). Results: The study evaluated 308 eyes of consecutive cataract surgery candidates with a mean age of 61.05 years ± 10.11 (SD). The mean AL and ACD were 23.20 ± 0.72 mm and 2.92 ± 0.37 mm respectively. The mean ± SD keratometry readings (K1 and K2) were 43.23 ± 1.49D and 44.29 ± 1.54D respectively.The mean K value was 43.75 ± 1.45D. The median corneal astigmatism was 1.00D. The mean ± SD and median of intra-ocular lens power were 21.60 ± 1.62D and 21.50D. Gender-based analysis of AL and K readings revealed statistically significant shorter AL in female eyes (22.92 ± 0.75mm) than in males (23.39 ± 0.64mm) (p=0.000), but more keratometric readings in females (44.06 ± 1.60D) than males (43.55 ± 1.30D) (p=0.003). The anterior chamber is deep in males as compared to females (2.93mm Vs 2.90mm). The mean ± SD IOL power was 21.30 ± 1.50D in males and 22.08 ± 1.70D in females (p=0.006). Against-the-rule astigmatism (ATR) was found in 177 eyes (57.50%). The axis of corneal astigmatism turned in the ATR direction with age. Conclusions: The mean AL was 23.20 ± 0.72mm, the mean K reading was 43.75 ± 1.45 diopter(D), and the mean ACD was 2.92 ± 0.37mm. The mean corneal astigmatism was 1.13D and the ATR axis was the predominant finding. Females had a statistically significantly shorter mean axial length as compared to males but more keratometric readings. The anterior chamber is deep in males as compared to females though not statistically significant. The mean IOL power needed to achieve emmetropia was 21.60D.