Significant univariate risk factors for pterygium
| Risk factor | Pterygium cases (n=142) | Controls (n=4902) | Test statistic | p Value |
| Mean age (SD) | 64.3 (12.6) | 60.3 (13.0) | 3.720 | 0.0003 |
| Log lifetime ocular sun (SD) | −0.08 (0.80) | −0.50 (0.63) | 5.82 | 0.0001 |
| Male (%) | 66.2 | 44.1 | 27.3 | 0.001 |
| Rural (%) | 68.3 | 27.7 | 110.7 | 0.001 |
| Smokers (%) | 14.7 | 17.5 | 32.8 | 0.001 |
| Percentage who take vitamin E | 3.6 | 9.0 | 5.0 | 0.03 |
| Percentage who take vitamin C | 3.6 | 11.2 | 8.20 | 0.004 |
| Percentage with cortical opacity >4/16 | 22.3 | 13.1 | 10.0 | 0.002 |
| Percentage with any PSC opacity | 12.4 | 5.7 | 10.8 | 0.001 |
| Percentage with nuclear opacity >2 | 25.6 | 16.0 | 9.0 | 0.003 |
| Percentage born in Australia | 83.8 | 64.6 | 21.6 | 0.001 |