Retinal Vascular Changes in Macular Telangiectasia Type 2 (MacTel2) using Wide-Field Swept-Source Optical Coherence Tomography Angiography (WF SS-OCTA)

Abstract

Purpose : MacTel2 is a primary retinal neurodegenerative disease with an unclear pathogenesis. Numerous imaging modalities have been used to characterize its unique findings, primarily focusing on the parafoveal region. We aim to describe more peripheral retinal vascular changes in MacTel2 using WF SS-OCTA.

Methods : We conducted a single center cross-sectional observational study (March 2019-January 2021), using WF SS-OCTA to obtain 12x12 mm scans centered on fovea. The ARI Network (Zeiss Portal v5.4) was used to quantify vascular metrics like vessel density (VD), vessel skeletonized density (VSD) in superficial capillary plexus (SCP), deep capillary plexus (DCP) and whole retina; and foveal avascular zone (FAZ) area, circularity and perimeter. Mixed-effects multiple regression models adjusting for age were used for statistical analysis.

Results : We included 38 MacTel2 eyes of 19 patients and 54 eyes of 35 patients as controls. The groups were matched based on age (median 58 vs 59 years, p=0.23), gender (p=0.31) and race (p=0.30). Thirteen MacTel2 patients (68.4%) had diabetes mellitus and/or hypertension, with no evidence of associated retinopathy. The central subsector of MacTel2 eyes showed a significant increase in the DCP VD (β=0.08, p<0.001) and VSD (β=2.86, p<0.001); and whole retina VD (β=0.06, p=0.02) and VSD (β=1.70, p=0.04). Conversely, when assessing beyond the parafoveal region, the outer nasal subsector had a significant decrease in SCP VD (β=-0.03, p=0.01) and VSD (β=-1.05, p=0.01); and the whole retina VD (β=-0.03, p=0.01) and VSD (β=-1.01, p=0.01). Additionally, the extended C1 nasal inferior subsector had a significant decrease in whole retina VSD (β=-0.52, p=0.048) only. There was no difference in the other subsectors vessel metrics or the FAZ parameters (p>0.05).

Conclusions : Herein, we present the first study to look at potential WF vascular changes in MacTel2 using WF OCTA. Our results demonstrate that the nasal region between the fovea and optic disc exhibit decreased vessel densities. Future studies correlating histology with WF OCTA may help to glean insights on its pathophysiology.

This is a 2021 Imaging in the Eye Conference abstract.

 

WF SS-OCTA of a MacTel2 eye

 

ETDRS grids overlaying the WF SS-OCTA heat map (C=Central disk, 1mm diameter; S=Superior; I=Inferior; T=Temporal; N=Nasal; I=Inner Ring, radius 0.5-1.5mm; O=Outer Ring, 1.5-3mm; Extended rings: C1, 3–4.5mm and C2, 4.5-6mm)