Peri-papillary retinal nerve fiber layer thickness profile in subjects with myopia measured using optical coherence tomography

Abstract

Aims: To evaluate the effect of myopia on peri-papillary retinal nerve fiber layer (RNFL) thickness in various quadrants and clock hour positions. Also, to evaluate the effect of myopia on the location of superotemporal and inferotemporal peak positions of peri-papillary RNFL. Setting and Design: Observational cross-sectional study from November 2011 to March 2013. Myopic patients between age group of 20-30 years were evaluated by spectral domain optical coherence tomography (SD-OCT). Materials and Methods: Myopic eyes were classified into three groups based on refractive error - Group 1: myopia up to 3 D (Diopter, D), Group 2: myopia of 3-6 D, and Group 3: Myopia > 6 D. OCT scan was done to measure peri-papillary RNFL and to locate superotemporal and inferotemporal peak positions. Statistical Analysis Used: Data was analyzed using one way ANOVA and post hoc analysis using Tukey′s test. Results and Conclusion: A total of 118 myopic eyes were evaluated. Eyes in Group 3 show significant thinning in 360 degree average RNFL thickness and in all quadrants except temporal as compared to Group 1 and 2. Correspondingly, in eyes with myopia > 6 D (as compared to Group 1 and 2), decrease in RNFL thickness is seen in all clock hour positions except 4, 8, 9, and 10. Also, in high myopia (>6 D), there is a significant shift in inferotemporal RNFL peak to temporal side while no significant change is noticed in superotemporal RNFL peak when compared to Groups 1 and 2. No significant difference was noted between Groups 1 and 2 in RNFL thickness profile and RNFL peak positions. While analyzing RNFL thickness in subjects with highly myopic eyes, this difference in topographic profile of RNFL thickness should be taken into consideration.

Keywords

• Myopia
• optical coherence tomography in myopic eyes
• peri-papillary retinal nerve fiber layer thickness