Assessment of retinal vascular alterations in eyes with retinal vein occlusion using single-capture 65°-widefield optical coherence tomography angiography.

Abstract

Purpose : To investigate vascular alterations in patients with retinal vein occlusion (RVO) using custom built widefield swept source optical coherence tomography angiography (SS-OCTA) and ultra-WF color fundus photography (UWF-CF).

Methods : Consecutive patients with RVO and symptoms over three months were recruited for cross-sectional single-capture 65°-WF-OCTA-imaging using a custom built SS-OCTA prototype (A-scan rate:1.7MHz). Additionally, UWF-CF (Clarus 700, Carl Zeiss Meditec Inc.) images were performed. Collateral vessels (CV), neovascularisation of the disc (NVD) or elsewhere (NVE), capillary distribution (CD, healthy vs entirely absent) within the central 5mm, foveal avascular zone (FAZ) and non-perfusion areas (NPA) were manually graded on an extended ETDRS-grid up to 18mm.

Results : 81 eyes of 81 patients (32 central RVO, 49 branch RVO) were included. CVs were found in 48.1% (n=39) and 34.6% (n=28) of eyes (p<0.01) and mean (±SD) number of isolated CVs was 5.8±4.5 and 5.1±4.1 in 65°-WF-OCTA and UWF-CF, respectively (p=0.67). In total, NVD (fine, raised vessels breaching into the vitreous) or peripapillary CVs (small, loopy vessels well differentiable from surrounding peripapillary capillaries) were visible in 8 eyes, although not distinguishable on UWF-CF. However, examination on 65°-WF-OCTA confirmed one eye with NVD, one eye with both NVD and NVE and one eye with NVE as well as 5 eyes with peripapillary CVs. On 65°-WF-OCTA, NPA were found in 71.6% (n=58) of eyes with a median (IQR) area of 27.5 (1.2-74.5) mm² . Mean number of intravitreal injections (11.9±11.0) showed no significant correlation with presence of NPA (r: 0.05; p=0.67). Mean FAZ area was 0.4±0.2 mm². Capillary distribution was healthy in 23 eyes (28.4%) and completely absent in at least one central 5mm subfield in 33 eyes (40.7%) on 65°-WF-OCTA.

Conclusions : 65°-WF-OCTA-imaging allows for precise non-invasive detection of vascular alterations in eyes with RVO and serves as a useful adjunct in detecting vascular characteristics in clinical practice.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1 Images from our dataset obtained using a modified Zeiss PlexElite system.
Top left: collateral vessels in branch RVO (73yo, f).
Bottom left: Neovascularisation elsewhere and non-perfusion area (NPA) in central RVO (68yo, f).
Right: NPA quantified in right eye with branch RVO (59 yo, f) using an extended ETDRS grid.