Optic disc topography in normal Indian eyes using spectral domain optical coherence tomography

PURPOSE: The aim was to study optic nerve head (ONH) parameters in normal Indian eyes using spectral domain optical coherence tomography (OCT)/scanning laser ophthamoscope (SLO). MATERIALS AND METHODS: One hundred and fifty-seven eyes of 157 normal subjects of various age groups underwent ONH imaging with spectral OCT/SLO and the parameters obtained were correlated with disc size. The effect of age, gender, and refractive error on various ONH parameters were also studied. RESULTS: The mean optic disc area was 3.36 ± 0.64 mm(2) (range, 2.13–5.08 mm(2)), mean rim area was 2.49 ± 0.58 mm(2) (range, 1.20–3.62 mm(2)), and mean cup area was 1.10 ± 0.75 mm(2) (range, 0–3.07 mm(2)). The disc area showed significant positive correlation with the rim area, cup area, horizontal cup disc ratio, vertical cup disc ratio, cup disc area ratio, mean cup depth, and maximum cup depth (P < 0.001). Neither gender nor refractive error showed any significant difference in various ONH parameters. ONH parameters did not show significant change with age except for rim area which declined with the advancing age (r = –0.25, P < 0.001). CONCLUSIONS: The quantitative measurement of ONH topography obtained with this study provides a normative database for an Indian population with spectral OCT/SLO. As optic disc area influences ONH topography, disc size should to be considered when evaluating optic disc for progressive optic neuropathies such as glaucoma.