Abstract
Purpose :
To evaluate changes in retinal deep capillary plexus (DCP) in diabetics with and without retinopathy, using OCT Angiography (OCT A) and compare with changes in the retinal inner nuclear layer (INL), where most of Müller cells are located.
Methods :
A retrospective detailed evaluation of OCT A and linear B scan images of 38 eyes/subjects (19 diabetics without diabetic retinopathy and 19 with non proliferative diabetic retinopathy) was performed. A population of 19 normal subjects/eyes served as control. On B scan Spectral Domain OCT, retinal layering was performed and the thickness (and morphology) of the inner nuclear layer (plus outer plexiform layer) was quantified. On OCT A images, the deep capillary plexus was identified and a qualitative analysis was performed. All gradings were performed twice, by two graders, in a masked fashion.
Results :
On OCT B scan the thickness of the inner nuclear layer increases with diabetes and progression of retinopathy (88.25.5μm vs 86.49.0μm vs 82.17.6μm, p<0.005). DCP shows progressing changes (vessel tortuosity, beadings and microaneurisms) when diabetes is present, which strictly correlates with INL thickness (p < 0.002). Normal controls have no signs of DCP microangiopathy. Intra-grader and inter-grader repeatability were excellent for all evaluations, for both INL thickness and OCT A.
Conclusions :
The development of diabetic retinopathy is related to some early changes in retinal inner nuclear layer and the deep retinal capillary plexus, as shown by OCT and OCT A images. Because inner nuclear layer is the site of the largest part of Müller cells, a still unknown strict relationship between Müller cells and retinal capillaries may be hypothesized in the pathophysiology of diabetic retinopathy, and it deserves further investigation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.