ASSESSMENT OF RNFL CHANGES IN GLAUCOMA AND OCULAR HYPERTENSION USING OPTICAL COHERENCE TOMOGRAPHY: A COMPARATIVE STUDY

Abstract

Introduction: This study evaluates and compares retinal nerve fiber layer (RNFL) thickness among glaucomatous, ocular hypertensive (OHT), and normal eyes using spectral-domain optical coherence tomography (SD-OCT), focusing on early RNFL changes and correlations with intraocular pressure (IOP) and visual field loss.

Material and Methods: A prospective study at Saveetha University, Chennai, included 60 participants divided into glaucoma (n=20), OHT (n=20), and normal (n=20) groups. Peripapillary RNFL thickness was measured globally and in four quadrants. The best-quality SD-OCT scan was analyzed, with a signal strength ≥7 considered acceptable. Statistical analysis included ANOVA and Pearson correlation.

Results: Glaucoma patients exhibited a 17.5% reduction in global RNFL thickness compared to normal eyes, with superior (24.9%) and inferior (33.8%) quadrants most affected. OHT patients showed an 8.25% reduction, indicating early structural changes. A negative correlation was observed between RNFL thickness and visual field loss (r = -0.36, p = 0.1232), supporting structural changes preceding functional deficits.

Conclusion: RNFL thinning is significant in glaucoma, with early changes detected in OHT patients, emphasizing OCT’s role in early detection and monitoring. Routine SD-OCT assessments can aid in pre-glaucomatous diagnosis and risk stratification for timely intervention. Further longitudinal studies are needed to establish RNFL thresholds for OHT-to-glaucoma conversion.