Corneal Curvature, Anterior Chamber Depth, Lens Thickness, And Vitreous Chamber Depth: Their Intercorrelations With Refractive Error In Saudi Adults

Ocular biometrics, such as corneal curvature, axial length, anterior chamber depth, and lens thickness, play a significant role in the development of refractive error and are essential in many clinical and research applications.

To determine means and ranges for corneal curvature, axial length, anterior chamber depth, lens thickness, vitreous chamber depth, and their intercorrelations with refractive error in Saudi adults.

A total of 120 eyes of 60 hyperopic and 60 myopic subjects aged 19-26 years old were enrolled in this comparative cross-sectional study. Axial Length (AL), Anterior Chamber Depth (ACD), Lens Thickness (LT), and Vitreous Chamber Depth (VCD) were measured by the SONOMED ultrasound E-Z SCAN AB5500+, A-scan, with a contact technique. An ophthalmometer measured the refractive status objectively by auto-refraction and the corneal radius of curvature.

The findings showed that the myopic eyes had a deeper ACD(3.70±0.27mm) than hyperopic eyes (3.28±0.32mm), P=0.0001. However, the hyperopic eyes had a thicker LT (3.84±0.24mm) than the myopic eyes (3.81±0.19mm), P=0.640. The mean of the corneal radius of curvature for the myopic eyes was slightly more curved (7.87±0.23mm) than for the hyperopic eyes (7.95±0.27mm), P=0.602. The myopic eyes had a higher axial length/corneal radius AL/CR ratio (3.12±0.11) than hyperopic eyes (2.89±0.06), with P=0.0001. Myopic spherical equivalent (SPH) positively correlated with VCD and AL/CR ratio, P=0.0001. Vitreous chamber depth/Axial length ratio (VCD/AL) in the myopic eyes was higher (0.693±0.041) than in the hyperopic eyes (0.677±0.018), P=0.000. Hyperopic SPH was positively associated with the VCD/AL ratio, P=0.0001.

Myopic eyes had a deeper VCD than hyperopic eyes; there was a strong positive correlation between VCD and myopic SPH. There was a strong positive correlation between the AL/CR ratio and myopic SPH and a VCD/AL ratio and the hyperopic SPH. Thus, the study suggests the possible utility of the AL/CR ratio while assessing the development of myopic refractive error and the VCD/AL ratio when evaluating hyperopic eyes and their associated complications.