Early Choroidal Microvascular Alterations Detected by Optical Coherence Tomography Angiography in Diabetic Eyes without Retinopathy.

PURPOSE: To evaluate early choroidal microvascular alterations in diabetic eyes without clinically detectable retinopathy using optical coherence tomography angiography (OCTA), with quantitative analysis of choriocapillaris (CC) flow voids and en face Haller layer metrics.

METHODS

This study included 102 eyes divided into three groups: healthy controls, diabetic patients without diabetic retinopathy (DR) (no DR group), and those with nonproliferative DR (NPDR group). Spectral-domain optical coherence tomography (OCT) and swept-source OCT were used to assess CC voids, Haller layer vessels, and subfoveal choroidal thickness (SFCT).

RESULTS

The average size and total area of CC voids significantly increased with DR severity, indicating early microvascular impairment. In contrast, there were no significant differences in the thickness or area of Haller layer vessels among the groups. CC void changes were independent of SFCT.

CONCLUSIONS

CC void parameters may serve as early imaging biomarkers of diabetic choroidopathy, even before the development of DR. These findings support the use of noninvasive OCTA as a tool for early detection and monitoring of choroidal changes in diabetic eyes.