Choriocapillaris structure in the fellow eye of neovascular age-related macular degeneration patients: an OCT angiography image averaging study

Abstract

Purpose : Histological choriocapillaris abnormalities are associated with age-related macular degeneration (AMD), but in vivo choriocapillaris imaging is challenging. Averaging multiple en face optical coherence tomography (OCT) angiography images allows the choriocapillaris to be visualized. This study used multiple en face swept-source OCT image averaging to examine choriocapillaris structural changes in the fellow eye of neovascular AMD patients.

Methods : All patients underwent macular OCT angiography imaging (3 × 3 mm² area, swept-source OCT [PLEX Elite 9000, Carl Zeiss Meditec]). The eye without neovascular AMD was repeatedly imaged to obtain 9 raster scan sets. Superficial capillary plexus images were used to perform registration so that deep capillary plexus and choriocapillaris images could be interpreted. Registered en face images were averaged and vessel density and choriocapillaris diameters were measured using ImageJ software.

Results : Twenty-four neovascular AMD patients (15 men, 9 women) were included (age = 76.8 ± 9.6 years). Fourteen eyes (54%) had polypoidal choroidal vasculopathy (PCV), 12 eyes (50%) had soft drusen, and 1 eye had reticular pseudodrusen (4.2%). The choriocapillaris had a meshwork appearance in all eyes. Choriocapillaris flow void area was 1.7 ± 0.4 mm², flow void density was 39.6 ± 10.4%, and individual flow void size was 1631.2 ± 1794.2 μm². The number of flow voids averaged 1480.6 ± 451.0. Vascular diameter index, defined as vessel density divided by vessel length density, was 5.6 ± 0.4. Flow void density was greater in eyes with (44.5 ± 12.4%) than without (34.7 ± 5.4 %) soft drusen (P = 0.025). Additionally, vascular diameter index was smaller in eyes with (5.5 ± 0.4) than without (5.8 ± 0.3) soft drusen (P = 0.020). Patients with PCV and typical AMD did not have a significant difference in flow void area (P = 0.771), individual flow void size (P = 0.954), number of flow voids (P = 0.534), or vascular diameter index (P = 0.500).

Conclusions : Multiple en face image averaging revealed precise choriocapillaris structures in the fellow eyes of neovascular AMD patients. Flow area and choriocapillaris diameter were reduced in eyes with soft drusen.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.