Table 1.
Optic disc measurements in a randomly selected sample of 70 subjects from Vellore, Tamil Nadu
| Mean (SD) | SE | Median | Range | |
| Optic disc | ||||
| Area (mm2) | 2.58 (0.65) | 0.08 | 2.44 | 1.43–5.15 |
| Disc area in women | 2.51 (0.53) | 0.08 | 2.42 | 1.43–3.60 |
| Disc area in men | 2.68 (0.81) | 0.15 | 2.56 | 1.44–5.15 |
| Disc diameter (mm) | ||||
| Horizontal | 1.77 (0.22) | 0.03 | 1.73 | 1.31–2.40 |
| Vertical | 1.87 (0.24) | 0.03 | 1.85 | 1.42–2.74 |
| Horizontal/vertical disc diameter | 1.06 (0.06) | 0.01 | 1.06 | 0.91–1.21 |
| Neuroretinal rim | ||||
| Area (mm2), total | 1.60 (0.37) | 0.04 | 1.50 | 1.08–2.85 |
| Temporal horizontal | 0.18 (0.07) | 0.01 | 0.16 | 0.07–0.37 |
| Temporal inferior | 0.42 (0.13) | 0.02 | 0.40 | 0.22–0.87 |
| Temporal superior | 0.43 (0.11) | 0.01 | 0.41 | 0.24–0.80 |
| Nasal | 0.58 (0.14) | 0.02 | 0.55 | 0.36–1.01 |
| Width (mm) | ||||
| Temporal horizontal | 0.19 (0.05) | 0.006 | 0.18 | 0.09–0.37 |
| Temporal inferior | 0.29 (0.06) | 0.007 | 0.28 | 0.20–0.44 |
| Temporal superior | 0.30 (0.06) | 0.007 | 0.30 | 0.18–0.53 |
| Nasal | 0.31 (0.05) | 0.006 | 0.30 | 0.20–0.50 |
| Inferior to temporal rim width ratio | 1.67 (0.54) | 0.06 | 1.58 | 1.02–3.83 |
| Superior to temporal rim width ratio | 1.71 (0.40) | 0.05 | 1.61 | 1.02–2.70 |
| Optic cup | ||||
| Area (mm2), total | 0.98 (0.40) | 0.05 | 0.88 | 0.22–2.30 |
| Diameter (mm) | ||||
| Horizontal | 1.16 (0.23) | 0.03 | 1.12 | 0.64–1.82 |
| Vertical | 1.06 (0.23) | 0.03 | 1.04 | 0.45–1.70 |
| Horizontal/vertical cup diameter ratio | 1.11 (0.12 | 0.01 | 1.07 | 0.84–1.43 |
| Cup/disc diameter ratios | ||||
| Horizontal | 0.66 (0.07) | 0.008 | 0.66 | 0.43–0.80 |
| Vertical | 0.56 (0.08) | 0.01 | 0.57 | 0.31–0.70 |
| Horizontal/vertical cup/disc diameter ratio | 1.18 (0.13) | 0.02 | 1.18 | 0.91–1.56 |
| Cup/disc area ratio | 0.37 (0.08) | 0.01 | 0.37 | 0.15–0.55 |
SD = standard deviation; SE = standard error.