Retinal Nerve Fiber Layer Thickness Analysis using Spectral Domain OCT in Glaucomatous Eyes in Central India

AIM: To study the retinal nerve fiber layer thickness (RNFL) using spectral domain optical coherence tomography (SD-OCT) in normal and glaucomatous eyes. DESIGN: cross sectional study METHODS: 50 eyes from 50 normal controls, 44 eyes of 26 ocular hypertension (OHT) and 46 eyes of 27 patients with primary open angle glaucoma (POAG) were included. Age between 40 to 80 years was selected with BCVA 6/12 or more with normal Visual Field. We studied average RNFL thickness, RNFL in each four quadrant, frequency distribution of BCVA and IOP with RNFL defect. RESULTS: Average RNFL was 121.6612.16, 106.896.91 and 90.4111.14 m in normal, OHT and POAG eyes respectively. Quadrant wise RNFL thickness in normal controls was greatest in inferior quadrant (141.9614.59), and gradually lesser in superior (138.0413.06), nasal (104.6012.00) and temporal quadrants (100.9211.34) m. In OHT patients, RNFL were greatest in superior (125.897.13) and thinned in the inferior (119.168.87), nasal (92.987.09) and temporal quadrants (88.987.03). Similarly in POAG group, RNFL was greatest in the superior quadrant (119.0911.20 m) and followed by inferior (107.2212.74 m), then nasal (7314.07 m) and then temporal quadrant (61.9811.20 m).75 % RNFL defect was seen in inferior quadrant in OHT group and (19.23 % and 32.31 %) defect was in inferior quadrant and temporal quadrant in POAG group. The mean (SD) IOP was 13.88 (1.98), 28.59 (4.11) and 29.91 (6.10) in group I, group II and group III respectively. CONCLUSION: SD-OCT has the ability to detect early glaucomatous change in the form of thinning of RNFL especially in inferior and temporal quadrants even in patients with BCVA of 6/6 and when the IOP was not very high.