Quantification of the retinal nerve fibre layer thickness in normal Indian eyes with optical coherence tomography.

ABSTRACT

PURPOSE: To quantitatively assess the normative values for peripapillary retinal nerve fibre layer (RNFL) thickness with Optical Coherence Tomography (OCT 3) in Indian subjects. METHODS: The peripapillary retinal nerve fibre layer of 146 normal subjects was imaged on OCT 3 in this cross-sectional study. Thickness of the RNFL around the disc was determined with three 3.4 mm diameter circle OCT scan. The RNFL thickness was measured in four quadrants; superior, nasal, inferior and temporal. The data was analysed using SAS commercial statistical software. Influence of age and gender was evaluated on various measured parameters using unpaired t test, one-way analysis variance (ANOVA) and Pearson's correlation coefficient. RESULTS: One hundred and forty six eyes of 146 patients, 84 males and 62 females were studied. The average RNFL thickness in the sample population under study was 104.27 +/- 8.51 (95% CI 87.25-121). The RNFL was thickest in the inferior quadrant, followed by the superior quadrant, and progressively less in nasal and temporal quadrant. The difference between inferior and superior quadrants was not statistically significant. Age had a significant negative correlation with average RNFL thickness (r = -0.321, P = 0.000) and with average superior (r = -0.233, P = 0.005) and average inferior RNFL thickness (r = -0.234, P = 0.004). There was no effect of gender on various RNFL thickness parameters. CONCLUSIONS: RNFL thickness is significantly correlated with age, but not with gender. This normative database of RNFL thickness with OCT in Indian eyes is similar to previously reported values in normal Asian eyes.