Superficial and deep network collaterals on wide field OCT angiography as apredictor of risk of neovascularisation in Branch retinal vein occlusion

Abstract

Purpose : The development of collaterals at the disc or retina in Branch retinal vein occlusion (BRVO) occurs secondary to increased hydrostatic pressure and hemodynamic overload, in an attempt to facilitate outflow of blood in a blocked vessel. Clinically visible collaterals take about 6 to 24 months to develop and have previously been associated with worse anatomical and functional outcomes. Wide field OCT angiography allows for a detailed visualisation of superficial and deep capillary plexus, with collaterals visible much earlier than clinical evaluation. We wanted the assess early detection of collaterals can predict the development of neovascularisation.

Methods : A retrospective review of records of all patients of BRVO with wide field OCT angiography ( Zeiss plex elite SS OCTA 12 by 12 montage) was done to look for the presence of collaterals in superficial and deep capillary plexus slabs. The patients were analysed as two groups (BRVO with and without collaterals) to assess for the extent of nonperfusion (CNP) and the incidence of neovascularisation (NV) in the two groups

Results : A total of 32 patients of BRVO had undergone widefield OCT angiography from November 2021 to December 2022. The average age at the presentation of all patients was 60.34 +/- 9.86 years with a mean duration of BRVO as 7.06 +/- 9.51 months. The main indication of advising wide field OCT angiography was to look for the extent of non perfusion and presence of neovascularisation followed by non resolving macular edema. 17 eyes showed the presence of superficial and deep collaterals. 2 out of 17 (11.76%) eyes had presence of NV while 6 out of 15 (40%) eye without collaterals showed the presence of NV (p=0.065, Chi square test).

Conclusions : This retrospective study highlights the early detection of collaterals on OCT angiography can help in understanding the future risk of neovascularisation and its sequelae in BRVO. A larger prospective study with follow-up on OCT angiography is needed to understand the natural course of BRVO.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.