Preclinical microvascular changes and functional deficits, detected by OCT angiography and central visual analyzer, may be early signs of developing diabetic retinopathy in patients with diabetes mellitus, according to a study.
Sixty eyes from 35 diabetic patients without diabetic retinopathy and 45 eyes from 31 nondiabetic controls were tested with OCTA for microcirculatory changes in the superficial capillary plexus and deep capillary plexus (DCP) and with central visual analyzer (CVA) for logMAR acuity and contrast sensitivity.
While the mean superficial capillary density was comparable in both groups, the mean deep capillary density was significantly lower in diabetic eyes. In the same group, the mean logMAR visual acuity was worse, with significant decrease of contrast sensitivity in the conditions simulating driving at dusk and dim-light reading.
“These results suggest that diabetic patients may develop an early capillary dropout at the DCP level and experience a decline in contrast sensitivity and visual acuity under glare conditions before the clinical expression of retinopathy compared with patients without diabetes,” the authors wrote.
The high resolution and segmentation abilities of OCTA and the high sensitivity of CVA effectively demonstrated that vascular and functional impairment coexist in diabetic patients and start developing before any manifest sign of diabetic retinopathy. This anatomical-functional coupling suggests that retinal neurons, glial cells and blood vessels should be considered as an integrated vascular unit, the authors noted.
They also observed that functional changes were more significant than the retinal capillary damage.
“This may imply that visual functional impairment is an earlier manifestation and a more sensitive indicator for neovascular damage in diabetes mellitus,” they concluded. – by Michela Cimberle
Disclosure: The authors reported no relevant financial disclosures.