Comparison of Retinal Nerve Fiber Layer Thickness in Glaucomatous and Nonglaucomatous Patients in Tertiary Care Hospital

BACKGROUND: Glaucoma is a chronic, progressive optic neuropathy and a leading cause of irreversible blindness worldwide. Structural damage to the retinal nerve fiber layer (RNFL) precedes visual field loss, making RNFL assessment a crucial parameter for early diagnosis. Spectral-domain optical coherence tomography (SD-OCT) enables objective and quantitative evaluation of RNFL thickness, facilitating early detection and monitoring of glaucomatous damage. AIM: The aim is to compare retinal nerve fiber layer thickness between glaucomatous and nonglaucomatous patients. MATERIALS AND METHODS: This cross-sectional comparative study was conducted in the Department of Ophthalmology at Aarupadai Veedu Medical College and Hospital, Puducherry, from July 2024 to December 2025. A total of 140 participants aged ≥ 40 years were enrolled using consecutive sampling and divided equally into glaucoma (Group A, n = 70) and control groups (Group B, n = 70). Comprehensive ophthalmic evaluation was performed, including intraocular pressure (IOP), gonioscopy, central corneal thickness (CCT), visual fields, and optic disc assessment. RNFL thickness (average and quadrant-wise) was measured using SD-OCT. Independent sample t-test was used to analyze between the two groups using SPSS version 26.0, with significance set at P < 0.05. RESULTS: The mean age was comparable between groups (P = 0.259). Glaucoma patients had significantly higher IOP and cup-to-disc ratio and significantly thinner CCT compared to controls (P < 0.05). RNFL thickness in the superior, inferior, nasal, and temporal quadrants, and average RNFL, was significantly reduced in the glaucoma group compared to controls (P < 0.01). CONCLUSION: Significant RNFL thinning was observed in glaucomatous patients compared to nonglaucomatous individuals. RNFL measurement using SD-OCT is a reliable and sensitive tool for early detection and evaluation of glaucomatous optic neuropathy.