ASSESSMENT OF MACULAR VOLUME AND RETINAL NERVE FIBER LAYER THICKNESS IN DIFFERENT DEGREES OF MYOPIA

Abstract

Background: Myopia is an increasingly prevalent refractive error and a growing global public health concern, with projections indicating that nearly half of the world’s population may be affected by 2050. Progressive myopia, particularly at higher degrees, is associated with structural retinal alterations that increase susceptibility to glaucomatous damage and myopic maculopathy. Among these changes, variations in retinal nerve fiber layer thickness and macular volume are clinically important, as they reflect retinal integrity and may serve as early indicators of disease-related complications.

Objective: To evaluate and compare macular volume and retinal nerve fiber layer thickness across different degrees of myopia.

Methods: A comparative cross-sectional study was conducted at The University of Lahore Teaching Hospital from November 2024 to February 2025. A total of 51 myopic eyes from participants aged 18–45 years were included. Based on refractive error, eyes were categorized into mild, moderate, and high myopia groups, with 17 eyes in each category. Comprehensive ophthalmic evaluation was performed, and retinal nerve fiber layer thickness and macular volume were measured using spectral-domain optical coherence tomography. Data were analyzed using SPSS version 25. One-way analysis of variance was applied to compare group means, followed by Tukey’s HSD post hoc test for pairwise comparisons, with statistical significance set at p < 0.05.

Results: Mean retinal nerve fiber layer thickness was 95.58 ± 12.19 µm in mild myopia, increased to 100.09 ± 9.61 µm in moderate myopia, and decreased markedly to 77.25 ± 2.75 µm in high myopia, with overall differences reaching statistical significance (p < 0.001). Macular volume demonstrated a similar pattern, measuring 8.36 ± 1.55 mm³ in mild myopia, 8.62 ± 1.55 mm³ in moderate myopia, and declining significantly to 6.39 ± 0.27 mm³ in high myopia (p < 0.05). The most pronounced reductions in both parameters were observed in the high myopia group.

Conclusion: High myopia was associated with significant thinning of the retinal nerve fiber layer and reduction in macular volume, highlighting the importance of early screening and regular retinal monitoring in myopic individuals to support timely detection of structural vulnerability and prevention of long-term visual impairment.