Details of a survey of patients with diabetes mellitus and retinitis pigmentosa
| Classification of diabetes | IDDM | NIDDM |
| Number of replies validated by doctor | 25 | 30 |
| Mean age (years (SD)) | 60.8 (16.8) | 65.5 (15.3) |
| Maximum, median, and minimum ages | 81, 61, 23 | 88, 67, 27 |
| Number of cases of diabetic retinopathy | 0 | 0 |
| Mean age at diagnosis of diabetes (years) | 35 | 48 |
| Mean duration of diabetes (years) | 19 | 14.5 |
| Interval between night blindness onset and diabetes onset (years) | 7.2 (n =10) | 19.5 (n =24) |
| Patients with other non-ocular complications of diabetes | 5 (n=11) | 8 (n =18) |