Abstract
Purpose :
Middle macular ischemic lesions termed “retinal ischemic perivascular lesions” (“RIPLs”) have recently been described as an independent correlate of cardiac disease and are some of the smallest lesions associated with the retinal ischemic cascade. Such lesions have yet to be quantitatively characterized in the superficial (SCP), intermediate (ICP), and deep (DCP) capillary plexuses. We investigated the effects of mild retinal ischemia with a prospective, cross-sectional, observational clinical study of the vessel linear density (VLD) of the SCP, ICP, and DCP at RIPLs in a cohort of patients without retinal disease.
Methods :
Patients between 55 and 89 years of age without documented retinal disease were approached in the ophthalmology clinic of our tertiary care center to receive voluntary SS-OCTA imaging between 9/2021 and 12/2022. Exclusion criteria included prior ocular surgery other than cataract surgery. PLEX Elite 9000 SS-OCTA 6mm x 6mm macular volume scans of each dilated eye were taken. RIPLs were manually identified in b-scans by three graders with a fourth resolving inter-grader queries. The manufacturer’s standard software was used to generate en face projections of the SCP and DCP. The manufacturer’s prototype research software and MATLAB were used to generate en face projections of the SCP, ICP, and DCP using previously described segmentation boundaries. 187.5μm- and 562.5μm-diameter circles centered on each RIPL were analyzed using FIJI and Python to yield VLD within the smaller circle and between the circles. Differences in mean SCP, ICP, and DCP VLD between the regions were analyzed with t-tests.
Results :
16 eyes of 8 patients (4 female) met inclusion and exclusion criteria and were included in the analysis. At least 1 RIPLs was found in 6 of 8 patients (8 of 16 eyes). Mean age was 67.8 years. For both the manufacturer’s standard algorithm and prototype algorithm, SCP VLD was no different at RIPLs than in the immediate surroundings (p=0.73 and p=0.93, respectively), while DCP VLD was reduced (p<10-4 and p<10-5, respectively). For the prototype algorithm, ICP VLD was also reduced at RIPLs relative to the immediate surroundings (p < 0.01).
Conclusions :
RIPLs are associated with local decreases in VLD in the DCP and ICP but not the SCP. Even in its earliest stages, mild middle retinal ischemia may damage the DCP and ICP without damaging the SCP.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.