Changes in foveal density and other parameters in diabetic eyes without clinically detectable diabetic retinopathy may be important biomarkers in diagnosing early diabetes, Turkish researchers say.

Their cross-sectional prospective study, published in the American Journal of Ophthalmology, enrolled 60 patients with diabetes but without clinically detectable diabetic retinopathy and 57 age-matched children in the control group. Researchers performed optical coherence tomography angiography (OCT-A) and analyzed several parameters, including: the foveal avascular zone and non-flow areas; superficial and deep vessel densities; foveal avascular zone perimeter; acircularity index of the foveal avascular zone (the ratio of the perimeter of the foveal avascular zone and the perimeter of a circle with equal area); and foveal density (vessel density in 300μm around the foveal avascular zone). The investigators then evaluated any correlations between the OCT-A parameters with diabetes duration and glycated hemoglobin (HbA1c) levels among the diabetes patients.

The study found statistically significant differences between the groups in foveal avascular zone perimeter, acircularity index of the foveal avascular zone and foveal density. Researchers also reported statistically significant differences between the groups for vessel densities in the deep superior hemi-parafovea and deep temporal parafovea, as well as the deep superior parafoveal zones. Additionally, investigators observed no significant correlations between diabetes duration and HbA1c levels on the OCT-A parameters.

Researchers said these new parameters might be sensitive imaging biomarkers to define early diabetic retinopathy.