Transscleral optical phase imaging in non-neovascular age-related macular degeneration

Abstract

Purpose : To report the results of transscleral optical phase imaging (TOPI) in age-related macular degeneration (AMD). This image modality has been developed to visualize in vivo the cellular structure of the human retinal pigment epithelium (RPE).

Methods : Non-neovascular AMD cases with clear optic media and good fixation were recruited for TOPI, associated with conventional imaging: spectral domain optical coherence tomography, autofluorescence, color and infrared fundus imaging. Six squares of 5.04x5.04 degrees were acquired with TOPI: one foveal, four localized in the macular quadrants with 3.8° eccentricity, and one to the investigators discretion. The TOPI images were optimized for contrast and confronted with information from conventional multimodal imaging.

Results : Included were 10 eyes of 8 AMD patients (mean age 75.5 years, 50% females).
Prominent features on the TOPI images were the reticular pattern of the choriocapillaris, particularly well contrasted on areas of geographic atrophy and RPE hypopigmentation, and the presence of additional dark spots irregularly distributed. Drusen showed dark with a white halo around. Within atrophic zones there were irregularly formed, sharply demarcated dark spots of variable size, correlating with degenerative remnants of RPE cells on OCT.
The dark spots were the dominating element for the image contrast, leading to very low contrast of the RPE cell visualization on the same image.

Conclusions : TOPI revealed in AMD the detailed structure of the choriocapillaris. Different types of dark spots were identified, corresponding to drusen and degenerated RPE cells.

This is a 2021 ARVO Annual Meeting abstract.

 

TOPI image from an AMD patient with focal geographic atrophy. The choriocapillaris shows as reticular background pattern. A typical drusen change is visible on the right side. a multitude of dark spots are visible in the atrophic area.