Axial Length to Corneal Radius of Curvature Ratio (AL/CR) and Refractive Errors in a Single Center Romanian Population

TL;DR

This study explores how the ratio of eye length to corneal curvature relates to refractive errors like myopia in a Romanian population.

Contribution

The study identifies the AL/CR ratio as a potential biomarker for refractive errors and their complications.

Findings

Myopic eyes had higher AL/CR ratios and lower corneal resistance compared to emmetropic and hyperopic eyes.

The AL/CR ratio correlated with axial length and anterior chamber depth in myopes and hyperopes.

Biomechanical and morphological differences were observed across refractive error groups.

Abstract

Background: Refractive errors are a common ophthalmological complaint, with a significant potential on the quality of life of our patients—myopia in particular has a growing incidence worldwide. Recent research focused on the ratio between the axial length of the eye (AL) and the corneal radius of curvature (CR), as it had proven valuable in refractive error diagnosis, and risk of progression and of complications. The objective of the study is to compare young emmetropic, hyperopic, and myopic eyes in terms of corneal biomechanics and ocular biometry, focusing on the AL/CR ratio. Methods: This cross-sectional study included 144 myopic eyes, 92 emmetropic eyes, and 47 hyperopic eyes. Measurements included cycloplegic autorefractometry (SE—spherical equivalent), Ocular Response Analyzer (CH—corneal hysteresis, CRF—corneal resistance factor), Aladdin biometry (AL, CR, ACD—anterior chamber depth, CCT—central corneal thickness, AL/CR ratio). Results: ACD, AL, and AL/CR were significantly higher and CCT, SE, CH, and CRF were lower in myopia. The AL/CR ratio correlated positively with AL and ACD and negatively with SE and CR in myopes and hyperopes, and correlated positively with AL and negatively with SE, CH, CRF, and CCT in emmetropes. Conclusions: The AL/CR ratio is significantly higher in myopes and significantly lower in hyperopes, compared to emmetropes, with differences also being in biomechanical properties (CH, CRF) and morphological ones (AL, CCT, ACD). This suggests the AL/CR ratio as a future potential biomarker for refractive errors, particularly for their risk of progression and complications.

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