Comparative analysis of retinal nerve fiber layer thickness between myopic and emmetropic eyes: Patterns of thinning and clinical implications

Introduction: Myopia is a significant risk factor for open-angle glaucoma, but diagnosing glaucoma in myopic patients remains challenging due to overlapping structural characteristics. Optical coherence tomography (OCT) is widely used to measure retinal nerve fiber layer (RNFL) thickness for glaucoma diagnosis; however, normative databases typically exclude individuals with high refractive errors. This study aimed to evaluate RNFL thickness in myopic patients compared to emmetropes and analyze quadrant-specific changes across varying degrees of myopia. Methods: This cross-sectional observational study included 120 subjects (60 myopes, 60 emmetropes) aged 20-35 years attending ophthalmology OPD at BGS Global Institute of Medical Sciences Hospital. Comprehensive ophthalmic examination including refractive error measurement and RNFL thickness assessment using Cirrus HD Spectral Domain OCT was performed. Myopes were categorized as low (-6D). Mean RNFL thickness was recorded globally and by quadrant. Results: Mean RNFL thickness was significantly lower in myopes (85.78±11.04 μm) compared to emmetropes (100.22±7.17 μm; p