Retinal Nerve Fiber Layer Thickness(RNFL) Measurements in Nepalese Population of Eastern Region by Optical Coherence Tomography

Abstract

Introduction: Glaucoma represents a group of disease defined by consistent remodeling of the connective tissue elements of the optic nerve head and with the loss of neural tissue of the retinal nerve fiber layer associated with the eventual development of distinctive patterns of visual function.1 OCT is used commonly to evaluate thinning of peripapillary retinal nerve fiber layer (RNFL) objectively and quantitatively, which is a hallmark for the diagnosis of glaucoma.2 As the OCT, normal database is commercially not available for Nepalese eyes. These measurements will provide a reference for the comparison and further evaluation of results of glaucoma and other patients with the help of OCT in the Nepalese Population.

Methods: 384 eyes of normal population RNFL thickness measurements were done with peripapillary SD-OCT (Cirrus HD OCT Model 5000/500; Carl Zeiss Meditec, Dublin, USA). Multiple regression analyses were applied to assess the effect of age and mean refractive error on peripapillary RNFL thickness.

Results: The average Retinal nerve fiber layer thickness (RNFLT) was highest in the age group 70-79 years (102.33 ±4.61µm) followed by age groups 50-59 years (93.89 ±5.89 µm) and 60-69 years (92.95 ±7.83 µm) respectively. The mean ± SD peripapillary RNFLT (µm) at the superior, inferior, nasal and temporal quadrants in the study population were 117.95±9.41µm, 120.71 ± 10.12 µm, 71.64 ±71.64 µm and 61.65±6.65µm respectively.

Conclusion: This study may serve as a reference in comparing changes in RNFL thickness during glaucoma screening with SD-OCT in this population.