Plexus-Specific Analysis of Capillary Non-perfusion along the Temporal Raphe in Eyes with Glaucomatous Damage

Abstract

Purpose : To assess retinal capillary non-perfusion at 4 different plexuses along the temporal raphe in glaucomatous eyes using OCT-A and to demonstrate their diagnostic capabilities in differentiating between eyes with glaucoma and healthy controls.

Methods : Twenty age matched controls and 17 patients with mild, moderate, and severe glaucomatous damage were imaged using a SDOCT system (Avanti RTVue-XR; Optovue). Ten 3x3mm scans centered at 9° temporal to the fovea were obtained and averaged (PMID:28068370). After the removal of large blood vessels on the OCT-A, capillary density (area, percentage) was analyzed on 4 different plexuses: superficial capillary plexus (SCP), intermediate capillary plexus (ICP), deep capillary plexus (DCP), and full capillary plexus (FCP).

Results : Median ± interquartile range for capillary density measured at the SCP, ICP, DCP, and FCP, were 30.4±3.9% (control) vs 22.9±7.2% (glaucoma), 43.0±1.3% vs 37.3±7.86%, 44.6±1.1% vs 43.9±1.3%, 47.1±2.0% vs 43.0±3.6%, respectively. Capillary densities measured at the SCP, ICP, and FCP were significantly lower in the glaucoma group compared to the control group (Mann–Whitney test, p<0.0001). In contrast, no significant difference was observed at the DCP between groups (Mann–Whitney test, p=0.13). In distinguishing between eyes with glaucomatous damage and controls, SCP and ICP showed the highest area under the receiver operating characteristic curve (AROC) of 0.935, followed by FCP (AROC=0.897) and DCP (AROC=0.647).

Conclusions : Reduced capillary density was found at the SCP and ICP, but not the DCP along the temporal raphe in eyes with glaucomatous damage (see Fig.). Further studies should focus on evaluating capillary density measured at the SCP and ICP as a diagnosis and prognostic clinical tool for early detection of glaucomatous damage.

This is a 2020 Imaging in the Eye Conference abstract.

 

Fig. Averaged OCT-R and OCT-A located at ~9° temporal to the fovea in (top row) a healthy control and (bottom row) a glaucoma patient. 1^st column) Superficial OCT-R s show intact RNFBs in the control and RNFB defect in the glaucoma patient. 2^nd -4^th column) Reduced capillary density was found at the superficial and intermediate plexuses with relatively intact deep plexus in the glaucoma patient as compared to the control. Fovea is to the left in all images.