Correlating microvascular changes on optical coherence tomography angiography with retinal sensitivity in diabetic retinopathy

Abstract

Purpose : Recent advances in optical coherence tomography angiography (OCTA) imaging allow high resolution visualization of vascular changes in both preclinical and established diabetic retinopathy (DR). However, it remains unclear whether these early vascular changes correspond to subclinical alterations in retinal sensitivity. This study aims to correlate the vascular changes observed on OCTA in diabetic patients with and without DR to retinal function as measured by microperimetry testing.

Methods : Diabetic patients with and without retinopathy, as well as age matched controls, were recruited from the New England Eye Center and underwent both OCTA imaging and microperimetry testing. The microperimetry stimulus-response exam was designed to standardize stimulus points in the central and inner sectors of the ETDRS grid based on degrees from the foveal center (Figure 1B). The points in each sector were summed, then divided by the sum of a perfect score to generate a grade per sector. An average sensitivity per sector was also calculated. En face OCTA images of the superficial and deep capillary plexuses were binarized and intercapillary space was calculated in the central and inner sectors of the ETDRS grid (Figure 1A), and these results were compared to the microperimetry calculations in the same regions.

Results : OCTA imaging and microperimetry were performed on 25 patients with diabetes and varying severities of retinopathy, as well as 5 healthy volunteers. Reduced sensitivity on microperimetry correlated with areas of higher intercapillary space.

Conclusions : The ability to visualize vascular changes and perhaps predict which of these changes will correlate with vision loss may be invaluable in testing earlier and more effective intervention for diabetic retinopathy.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1. Example of registration between a processed OCTA image and microperimetry exam results using the central and inner sectors of the ETDRS grid from a patient with proliferative diabetic retinopathy. (A) 3mm x 3mm binarized OCTA image of the superficial capillary plexus divided into 5 regions for analysis. (B) Microperimetry stimulus-response results from the same patient depicting the distribution of stimulus points per region.