Changes in Choroidal Thickness and Choroidal Vascularity Index Measurements using Widefield SS-OCT Imaging in Patients with Diseases that Affect Choroidal Blood Flow

Abstract

Purpose : To report the changes in choroidal thickness (CT) and the choroidal vascularity index (CVI) measurements using widefield SS-OCT imaging in a series of patients undergoing treatments that should alter choroidal blood flow.

Methods : All patients were enrolled in an ongoing IRB-approved prospective SS-OCT imaging study. Patients underwent 12x12mm SS-OCT angiography scans (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, CA) centered on the fovea. The scans consisted of 500 A-scans per B-scan with 500 B-scans repeated twice at each position. Patients undergoing internal carotid stenting secondary to carotid stenosis, orbital decompression secondary to Graves orbitopathy, and closure of carotid-cavernous (CC) sinus fistulas were imaged. Imaging was performed before and after the procedures. Automated choroidal segmentation algorithms applied to OCT structural scans were used to measure the choroidal thickness (CT) and choroid vascularity index (CVI) throughout the12X12mm scan area.

Results : Three patients have been imaged with follow-up completed. The first patient had a history of intermediate AMD and underwent left carotid stenting for carotid stenosis. The second patient had a right-sided C-C fistula and underwent neuro-interventional coiling. The third patient had advanced Graves ophthalmopathy and underwent orbital decompression surgery. The first patient with carotid stenosis had a pre-treatment mean CT measurement of 269.2μm that decreased to 237.5μm and a pre-treatment mean CVI of 0.62 that decreased to 0.60 after the stenting procedure. The second patient with the C-C fistula showed a decrease in mean CT from 317.5 μm to 189.5μm and a decrease in mean CVI from 0.59 to 0.58. The third patient with Graves orbitopathy showed an increase in mean CT from 196.2μm to 313.7μm and an increase in mean CVI from 0.58 to 0.60 (See Figure).

Conclusions : The ability to use widefield SS-OCT imaging combined with automated algorithms to assess changes in CT and CVI measurements in diseases that affect choroidal blood flow should lead to a better understanding of choroidal autoregulation and help clinicians decide when best to intervene and help assess the benefits of various treatments. Ten additional patients have been imaged, but follow-up has not been completed.

This is a 2020 Imaging in the Eye Conference abstract.