Demographic and clinical data of the control group and NDR group
| Characteristics | Control group (n=62) | NDR group (n=66) | P value |
| Age (years) | 55.16±12.50 | 58.77±12.13 | 0.100 |
| Gender (male/female) | 31/31 | 38/28 | 0.390 |
| Eye (right /left) | 30/32 | 35/31 | 0.599 |
| Duration of diabetes (years) | NA | 8.65±6.50 | NA |
| HbA1c (%) | NA | 9.21±2.54 | NA |
HbA1c, glycated haemoglobulin; NA, not applicable; NDR, patients with diabetes without clinically detectable retinopathy.