An assessment of variation in macular volume and RNFL thickness in myopes using OCT and their significance for early diagnosis of primary open-angle glaucoma

Abstract

Purpose: An assessment of variation in Macular Volume and RNFL Thickness in myopes using OCT, and their significance for early diagnosis of Primary Open Angle Glaucoma( POAG). Materials and Method: Total of 122 eyes of 61 Indian Myopic subjects of both sex and various age groups underwent retinal nerve fiber layer thickness, macular volume in 6mm analysis by Rtvue Avanti SD-OCT, Optovue Technology V6.1.1, after taking due consent from ethical committee. Subjects were divided into two groups based on their refractive error, Group A <6 D and Group B >6D. The results were evaluated to determine the above mentioned measurements and their variation with myopic refractive error. Results: The RNFL thickness in four Quadrants and an inner circle were taken. The mean thickness in inner circle in both groups were 101.48μm (SD±13.34 μm) and 92.38 μm (SD±11.99μm) respectively, which was statistically significant. The difference was also significant in superior, nasal and inferior quadrant. Statistically the difference was not significant in temporal quadrant. The macular volume was calculated in 6mm diameter. The mean value in Group A was 7.82mm3±0.54 mm3. The mean value in Group B was 7.44mm3±0.98mm3. The statistical analysis showed the difference between the two groups is statistically significant. Conclusion: RNFL thickness is an established way to diagnose open angle glaucoma in preperimetric stage. Macular Volume is also found to be co-related with the risk. Myopes are known to be at higher risk to develop POAG. Hence, measurement of RNFL thickness by OCT should be made a mandatory investigation in High Myopes.