Disruption of the Retinal Parafoveal Capillary Network in Type 2 Diabetes before the Onset of Diabetic Retinopathy

Abstract

It is often difficult to find consistent changes in the retinal microvasculature due to large intersubject variability. However, with a novel application of AOSLO imaging, it is possible to visualize parafoveal capillaries and identify AV channels noninvasively. AV channels are disrupted in type 2 diabetes, even before the onset of diabetic retinopathy.

In vivo adaptive optics microvascular imaging in diabetic patients without clinically severe diabetic retinopathy

“…Our results, together with the results of Tam [22,25], make a strong case that the current classifications of diabetic retinopathy that are based on lower resolution and lower contrast imaging methods provide insufficient specific information about the status of the retina. Imaging with AO opens the possibility of distinguishing among patients who are undergoing retinal changes that permanently threaten sight.…”

“…The use of adaptive optics has allowed precise measurements of many cell types in the retina, including photoreceptors [1][2][3][4][5][6][7][8][9], retinal pigment epithelial (RPE) [10][11][12][13] cells, ganglion cell axon bundles [14,15], and erythrocytes [16][17][18][19]. Correcting the wavefront aberrations has also allowed imaging of capillaries at high resolution; increasing contrast and allowing detailed imaging of the perifoveal capillary network [18,[20][21][22][23][24]. The most sensitive of these cellular techniques have usually used confocal imaging, including the use of adaptive optics with OCT. Adaptive optics retinal imaging has been used to study diabetic retinal changes at high magnification [22,[25][26][27].…”

“…Correcting the wavefront aberrations has also allowed imaging of capillaries at high resolution; increasing contrast and allowing detailed imaging of the perifoveal capillary network [18,[20][21][22][23][24]. The most sensitive of these cellular techniques have usually used confocal imaging, including the use of adaptive optics with OCT. Adaptive optics retinal imaging has been used to study diabetic retinal changes at high magnification [22,[25][26][27]. [22,25] Tam and colleagues [22,25] showed that the capillary network can be quantified using motion contrast techniques and that it was changing early in diabetes, and Lombardo and colleagues [27] showed capillary diameter changes using a flood illuminated AO system.…”

“…The most sensitive of these cellular techniques have usually used confocal imaging, including the use of adaptive optics with OCT. Adaptive optics retinal imaging has been used to study diabetic retinal changes at high magnification [22,[25][26][27]. [22,25] Tam and colleagues [22,25] showed that the capillary network can be quantified using motion contrast techniques and that it was changing early in diabetes, and Lombardo and colleagues [27] showed capillary diameter changes using a flood illuminated AO system. However confocal AO imaging while producing high contrast and allowing excellent mapping using motion contrast procedures, does not always produce the best structural images of the blood vessels [18].…”

“…These signs of diabetic retinopathy, the hard exudates, NVD and NVE, are quite evident using traditional imaging techniques. However, the earlier vascular changes such as IRMA and capillary nonperfusion [22,[35][36][37]39] are not always evident clinically. With the development of novel therapies and interventions for diabetic control, there is a growing importance for monitoring the early stages of diabetic retinopathy [33].…”