Assessment of Detailed Photoreceptor Structure and Retinal Sensitivity in Diabetic Macular Ischemia Using Adaptive Optics-OCT and Microperimetry

Abstract

Purpose The purpose of this study was to assess density and morphology of cone photoreceptors (PRs) and corresponding retinal sensitivity in ischemic compared to nonischemic retinal capillary areas of diabetic eyes using adaptive optics optical coherence tomography (AO-OCT) and microperimetry (MP). Methods In this cross-sectional, observational study five eyes of four patients (2 eyes with proliferative diabetic retinopathy (DR) and 3 eyes moderate nonproliferative DR) were included. PR morphology and density was manually assessed in AO-OCT en face images both at the axial position of the inner-segment outer segment (IS/OS) and cone outer segment tips (COSTs). Retinal sensitivity was determined by fundus-controlled microperimetry in corresponding areas (MP-3, Nidek). Results In AO-OCT, areas affected by capillary nonperfusion showed severe alterations of cone PR morphology at IS/OS and COST compared to areas with intact capillary perfusion (84% and 87% vs. 9% and 8% of area affected for IS/OS and COST, respectively). Mean reduction of PR signal density in affected areas compared to those with intact superficial capillary plexus (SCP) and deep capillary plexus (DCP) perfusion of similar eccentricity was –38% at the level of IS/OS ( P = 0.01) and –39% at the level of COST ( P = 0.01). Mean retinal sensitivity was 10.8 ± 5.4 in areas affected by DCP nonperfusion and 28.2 ± 1.5 outside these areas ( P < 0.001). Conclusions Cone PR morphology and signal density are severely altered in areas of capillary nonperfusion. These structural changes are accompanied by a severe reduction of retinal sensitivity, indicating the importance of preventing impaired capillary circulation in patients with DR.

Association of macular structure with microperimetry sensitivity following vitrectomy for proliferate diabetic retinopathy

“…In previous study, it was also found that in patients with DR, the macular mean sensitivity decreased along with a decrease in DCP vessel perfusion. 21 Using adaptive optics scanning laser ophthalmoscopy, it was also found that PR heterogeneity packing index had a significant correlation with DCP vessel density in patients with DR. 22 This study had several limitations. This study only followed up patients with PDR after vitrectomy, and there was a lack of studies on non-proliferative diabetic retinopathy and non-DR patients.…”

“…In previous study, it was also found that in patients with DR, the macular mean sensitivity decreased along with a decrease in DCP vessel perfusion. 21 Using adaptive optics scanning laser ophthalmoscopy, it was also found that PR heterogeneity packing index had a significant correlation with DCP vessel density in patients with DR. 22…”

Point-to-point associations of drusen and hyperreflective foci volumes with retinal sensitivity in non-exudative age-related macular degeneration

“…Photoreceptor integrity and retinal sensitivity assessed by microperimetry are closely linked and can be assessed using the combination of adaptive optics OCT and microperimetry [ 27 , 28 ]. Since the RPE is strongly involved in the nourishment of photoreceptors, it becomes apparent that increased degeneration of the RPE might ultimately result in reduced photoreceptor function [ 29 ].…”

Peripheral and central capillary non-perfusion in diabetic retinopathy: An updated overview

“…Moreover, non-perfusion in the DCP correlates with microstructural changes indicating photoreceptor damage, such as ellipsoid zone and external limiting membrane disruption and outer nuclear layer focal thinning ( 47 ). Recent studies involving adaptive optics-OCT unveiled severely altered morphology and density of cone photoreceptors in areas of CNP, together with a strong reduction of retinal sensitivity ( 48 ).…”