Retinal nerve fibre layer analysis in primary open angle glaucoma

Background: POAG occurs in elderly, rarely seen earlier than 40 years of age and tends to run in families. Glaucoma is a neurodegenerative disease characterized by the slow, progressive degeneration of retinal ganglion cells. Aim: To study the changes, in retinal nerve fibre layer thickness in primary open angle glaucoma (POAG). Materials and methods: The present cross sectional study was carried out at a tertiary care hospital in North India. 100 patients of primary open angle glaucoma were matched with 100 controls and evaluated with the aim to assess their RNFL thickness and compare with each other. Results: The data distribution analysis of retinal nerve fibre layer thickness in different optic nerve head quadrants in POAG group in relation to overall severity of glaucoma shows that in superior quadrant maximum number of patients in preperimetric group 6 (50%) cases, in mild 9 (45%) cases and in moderate group 25 (44.6%) were in the range 100±10μm. But in severe glaucoma cases majority 7 (58.3%) cases had the RNFL thickness in the range of 60±10 μm. The temporal quadrant RNFL thickness was least in all grades of severity of glaucoma i.e. preperimetric 6 (50%), in mild cases 9 (45%), in moderate 25 (44.6%) cases and in severe 8 (66.7%) cases. Conclusion: Overall RNFL thickness variation, regardless of severity of glaucoma, follow the normal pattern of thickness being thicker in superior and inferior quadrant compared to nasal and temporal quadrant. It was interesting to note that the RNFL thickness in all the quadrants of optic nerve head area continues to become thinner as the severity of glaucoma increases.