Previous research has established the substantial impact of diabetic retinopathy (DR) and vision impairment in Black patients, but a new study that looked at the pathophysiology of DR found those with diabetes may have alterations in both their retinal vascular structure and oxygen saturation (SO2) , a finding that could potentially pave the way for future investigations into race-specific biomarkers in the assessment of DR.

The investigation, published online in BMC Ophthalmology, included 56 Black subjects. The researchers considered SO2, vessel diameter and tortuosity in DR severity stages. Right eyes were grouped as non-diabetic, no clinical DR, or moderate/severe non-proliferative DR (NPDR). The researchers conducted imaging with a scanning laser ophthalmoscope to determine retinal arterial and venous SO2, diameter and vessel tortuosity.

The study reported venous diameter and SO2 levels were higher in the moderate/severe non-proliferative DR group compared with the non-diabetic and no clinical DR groups. No significant differences were noted in the arterial diameter and SO2 and between the three groups.

The researchers found the  maximum arterial vessel tortuosity was higher in diabetic patients (no clinical DR and NPDR) compared with unaffected subjects. Additionally, they noted no significant difference in maximum venous vessel tortuosity among the three groups.

This is the first report to assess retinal vascular oxygenation and vessel morphology at stages of DR and specifically in Black subjects, the researchers noted. The findings have the potential to stimulate future studies aimed at identification of race-specific biomarkers that may help reduce the risk of vision loss due to DR in the Black population, they added.

Garvey SL, Khansari MM, Jiang X, et al. Assessment of retinal vascular oxygenation and morphology at stages of diabetic retinopathy in African Americans. BMC Ophthalmology. July 18, 2020. [Epub ahead of print].