Analysis of retinal nerve fiber layer thickness using optical coherence tomography in normal South Indian population

Abstract

Introduction: The high resolution optical coherence tomography (OCT) is a new technique, which allows precise measurement of retinal thickness as well visualization of intraretinal layers, particularly the retinal nerve fiber layer (RNFL). RNFL is a very sensitive structure, which gets damaged in various disease processes. Spectral domain OCT has been recently introduced in India and the normative profile of various measurements has not been established for the Indian population. Purpose of this study is to use OCT to evaluate the peripapillary variation in RNFL thickness in normal South Indian population. Materials and Methods: The study groups included 60 eyes of 30 normal individuals who underwent RNFL analysis using Topcon three-dimensional-OCT 2000. Descriptive statistical analysis has been carried out in the present study and significance was assessed at 5% level of significance. Paired t-test was used to obtain the P value. Results: In this study, average nerve fiber layer thickness along the 3.4-mm-diameter circle around the optic nerve head was 111.75 ± 4.83 μm. RNFL thickness was found to be more in the inferior quadrant followed by superior, nasal and temporal quadrant, suggesting that ISNT rule does apply to this subgroup of Indian population. Conclusion: This study concludes that RNFL thickness can be measured effectively using spectral domain OCT and should be considered while evaluating patients for diagnosis and follow-up of glaucoma. The normative data provided by this study may assist in identifying changes in RNFL thickness in glaucoma and other optic nerve diseases in South Indian population.

Keywords

• Optic nerve diseases
• optical coherence tomography
• retinal nerve fiber layer
• South Indian population