Axial length in patients with diabetes

Purpose: To investigate the relationship between axial length and retinal involvement in patients with diabetes. Methods: A total of 157 consecutive patients with diabetes underwent biometry. The patients were divided into three groups, according to retinopathy: 44 without retinopathy, 37 with background retinopathy, and 76 with proliferative retinopathy. To compare axial length in diabetic versus nondiabetic subjects, a control group of 157 healthy subjects with age and sex distribution similar to the diabetic group was selected from an orthopedic clinic. We investigated in the diabetic group whether the axial length was related to specific type of diabetes (non- insulin-dependent or insulin-dependent), duration of disease, presence of retinopathy, or laser treatment. To eliminate the confounding effect of myopia, we excluded all patients with axial length greater than 24 mm from the two groups. Comparison of diabetic patients without retinopathy versus nondiabetic subjects was also performed. Results: Diabetic patients presented shorter axial lengths compared with the controls (mean ± standard deviation, 22.4 ± 1.3 mm versus 23.4 ± 1.3 mm; P <0.001). Significantly shorter axial lengths were found in the background and proliferative retinopathy groups compared with the group without retinopathy (22.0 ± 1.2 mm and 22.1 ± 1.1 mm versus 23.2 ± 1.4 mm, respectively; P <0.05). No difference in axial length was found between the diabetic patients without retinopathy and the nondiabetic subjects (P = 0.3). Multivariate analyses showed that retinopathy was negatively correlated with axial length (P <0.01). Including only the patients with axial length under 24 mm, we obtained similar results. Conclusion: Axial length is shorter in diabetic patients than in nondiabetic subjects. Within the diabetic group, patients with retinopathy had shorter axial lengths than did patients without retinopathy.