Abstract
Purpose :
Diabetic retinopathy (DR) is a microvascular, neurodegenerative and inflammatory disease, where microglia, the resident monocytes of the retina, are activated. In this study, we investigate the capability of adaptive optics optical coherence tomography (AO-OCT) to visualize the inflammatory component of the disease.
Methods :
Ten eyes of 7 diabetic patients with mild NPDR (n=3), moderate NPDR (n=4), severe NPDR (n=3) and 7 eyes of 7 healthy controls were investigated with a prototype pyramid wavefront sensor (P-WFS) AO-OCT at the Medical University of Vienna. AO-OCT volumes were recorded at an extended field of view (FoV) of 4°x4° with a recording time of 2.4 seconds for one volume. Several different locations along the superior vessel arc are investigated.
Results :
We report in vivo imaging of microglia at different retinal layers in healthy (female n=2) and diabetic subjects (female n=2). Microglia present with an hyperreflective round cellular body and a variable number of long branching processes. Microglia were identifiable in all healthy and diabetic subjects on the inner surface of the ILM. In the ONL microglia were exclusively present in diabetic eyes of all stages of NPDR. The diameter of the microglial nucleus ranges between 14.28 - 14.4 µm in healthy and 12.62 - 14.13 µm in diabetic eyes. The length of the microglial processes measure between 31.39 – 66.12 µm in healthy and 53.23 – 63.13 µm in diabetic eyes.
Conclusions :
AO-OCT enables the quantitative assessment of microglial ultrastructures in healthy and diabetic eyes. While anterior to the ILM microglia were found in both study populations, a presence of microglia in the ONL was only found in eyes with DR and may potentially indicate a biomarker for inflammatory processes in these patients, subject to further investigation in future studies.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.