Purchase this article with an account.
Johnny Tam, Kavita P. Dhamdhere, Pavan Tiruveedhula, Silvestre Manzanera, Shirin Barez, Marcus A. Bearse, Jr., Anthony J. Adams, Austin Roorda; Noninvasive Assessment Of Parafoveal Capillaries In Type 2 Diabetes Prior To Onset Of Diabetic Retinopathy. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4416.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the appearance of the parafoveal capillary network in adult subjects with Type 2 diabetes prior to the onset of diabetic retinopathy, using adaptive optics scanning laser ophthalmoscopy (AOSLO).
12 adult subjects with Type 2 diabetes and no diabetic retinopathy (age 55.5 +/- 7.8) were compared to 11 control subjects with no diabetes (age 52.2 +/- 10.6). AOSLO videos were acquired in the parafoveal region of one eye from each subject; for the subjects with diabetes, the absence of retinopathy was confirmed by grading of color fundus photographs by a retina specialist. Images of the parafoveal capillary network were generated using offline motion contrast analysis. These images were used to compare the two groups. The comparison included qualitative assessment of vascular features (loops and microaneurysms) as well as quantitative assessment of foveal avascular zone (FAZ) size and shape, capillary density (CD), and tortuosity of arterio-venous (AV) channels. AV channels were identified as the least tortuous capillary paths connecting arteries to veins.
Loops and microaneurysm-like features were observed in both groups. In general, diabetic retinas (D) had more total features than control retinas (C). Comparing D to C, FAZ size was increased, but not significantly (p=0.42; n=12D,11C); FAZ shape was altered, but not significantly (p=0.48; n=9D,11C); and capillary density within 0.15 degrees of the edge of the FAZ was decreased, but not significantly (p=0.48; n=9D,8C). The tortuosity of AV channels was significantly increased (p<0.05; n=11D,8C).
It is often difficult to find consistent changes in the microvasculature due to large intersubject variability. However, AOSLO imaging can be used to noninvasively visualize parafoveal capillaries and identify AV channels, which appear to be altered in Type 2 diabetes even before onset of diabetic retinopathy.
This PDF is available to Subscribers Only