An assessment of the thickness of the retinal nerve fiber layer around the optic disc using spectral domain optical coherence tomography in myopia patients at an industrial hospital in India

Abstract

Myopia is rising as a silent epidemic across the globe with marked ocular morbidity and pathological changes. The retinal nerve fiber layer (RNFL) thinning is indicative of glaucomatous damage; it remains uncertain whether RNFL thickness would vary with the refractive status of the eye. It is therefore important to investigate whether any correlation exists between RNFL measurements and axial length/refractive error in myopia. Purpose. To assess the peripapillary RNFL thickness by spectral domain optical coherence tomography (SD-OCT) and to determine the correlation between axial length and peripapillary RNFL thickness in myopia patients. Material and methods. A total of 100 patients (200 eyes) with low, moderate and high myopia (ave -3.58 ± 2.45 D) aged 15 to 40 years were examined to assess the peripapillary RNFL thickness by SD-OCT and to determine the correlation between axial length (AL) and peripapillary RNFL thickness myopia patients. Results. Average 360-degree RNFL thickness (mean ± SD) was 92.25 ± 10.04 μm. In the low myopic group this parameter was 98.82 ± 6.67 μm, in the moderate myopic group — 89.28±5.23 μm, and in the high myopic group — 78.54 ± 7.32 μm. The average 360-degree mean RNFL thickness in patients with AL < 24 mm was 100.06 ± 5.92 μm, in patients with AL between 24–26 mm — 89.48 ± 4.59 μm, and in patients with AL > 26 mm — 78.2 ± 6.77 μm. There was significant association between thinning of the average 360-degree RNFL thickness with increasing degree of myopia and AL (p < 0.0001). Conclusion. The study shows RNFL thickness decreases with increase in refractive error and increase in axial length of myopic eyes. The degree of myopia may affect the RNFL thickness differently.