Demographics
| Pterygium cases | Controls | p | |
| Sex (n (%)) | |||
| Female | 8440 (36) | 8440 (36) | |
| Male | 15 185 (64) | 15 185 (64) | |
| Total | 23 625 (100) | 23 625 (100) | |
| Age at the Index date (n (%)) | |||
| <50 years | 11 603 (49) | 11 574 (49) | |
| ≥50 years | 12 022 (51) | 12 051 (51) | |
| Mean (SD) | 50 (±16) | 50 (±16) | |
| Residence (n (%)) | |||
| Urban | 16 384 (69) | 16 213 (68) | |
| Rural or remote | 6316 (27) | 6530 (28) | |
| Tropical | 925 (4) | 882 (4) | |
| Deaths (n (%)) | 3653 (15) | 4269 (18) | <0.001 |
| Cutaneous melanoma (n (%)) | |||
| Malignant | 646 (2.7) | 530 (2.2) | <0.001 |
| In situ | 437 (1.8) | 344 (1.5) | <0.001 |
| Total | 1083 (4.6) | 874 (3.7) | <0.001 |