Choroidal thickness in diabetic retinopathy in relation to long-term systemic treatments for diabetes mellitus.

PURPOSE

To measure central choroidal thickness (CCT) in patients with diabetic retinopathy (DR) and analyze the correlation with clinical backgrounds regarding medications for diabetes mellitus (DM).

METHODS

We retrospectively identified 86 patients with DR (172 eyes) and 43 healthy subjects (57 eyes) who underwent spectral-domain optical coherence tomography. Among the 86 patients with DM who had received no intraocular treatments, 61 were diabetic patients who had continuously received systemic treatments for DM (under treatment group). Twenty-five were patients who had discontinued the treatments or had not received any treatment for DM until this study started (no treatment group).

RESULTS

The results of CCT acquired by 2 masked raters showed a significant correlation coefficient (r = 0.98), indicating high reproducibility in this study. No correlation of CCT was noted between normal (272 ± 71 µm) and DM eyes (264 ± 77 µm), the presence of diabetic macular edema, or CCT and the severity of DR in the patients examined. Interestingly, there was a significant decrease in CCT (175 ± 42 µm) in eyes with mild/moderate nonproliferative DR (NPDR) in the no treatment group (p<0.05), whereas CCT was prominently thicker in eyes with severe NPDR (354 ± 76 µm) and proliferative DR (286 ± 74 µm) than in eyes without DR.

CONCLUSIONS

This study demonstrated that CCT was significantly decreased in the presence of mild/moderate NPDR in the no treatment group, suggesting that a continuously high blood sugar state caused by insufficient treatments for DM may facilitate vascular damage in the choroid in the early stage of DR.