DR patients were observed in this study to have thinner choroids before the disease progressed to PDR. Photo: Jay M. Haynie, OD. Click image to enlarge.

A recent study evaluating choroidal thickness in eyes with diabetic retinopathy (DR) reported that patients have significantly thinner choroids compared with controls and that thinning progresses proportionally to disease severity up to nonproliferative DR (NPDR), after which thickening occurs with progression to proliferative DR (PDR) without approaching a normal level.

The cross-sectional study grouped 176 eyes of 93 patients as no DR, NPDR, PDR or control. Each participant underwent choroidal thickness and volume measurements on OCT and enhanced-depth imaging OCT.

The researchers also noted in their study that fasting blood sugar and diabetes duration had no observed effect on choroidal thickness. Additionally, they found that BCVA, diabetic macular edema and foveal avascular zone weren’t affected by choroidal thickness or volume.

They pointed out that persistent choroidal thinning up to NPDR may “herald progressive vasculopathy.” They also suggested the increase in thickness in PDR may be VEGF-related. They believe that if future studies also demonstrate a lack of relationship between choroidal thickness and diabetic macular edema, this may mean there’s no association between the choroid and retina in terms of VEGF production.