Drusen Characteristics Detected By Polarization-Sensitive Optical Coherence Tomography in Age-Related Macular Degeneration

Abstract

Purpose: : Aim of this study was to characterize the different appearances of drusen and subretinal drusenoid deposits (SDD) imaged with Polarization-Sensitive Optical Coherence Tomography (PS-OCT) in patients with non-atrophic and non-neovascular age-related macular degeneration (AMD).

Methods: : Twenty eyes of 20 patients with drusen of AREDS 2/3 classification were examined with the PS-OCT engineered by the Center for Medical Physics and Biomedical Engineering Vienna. The study adhered to the declaration of Helsinki. Each individual B-scan was examined by two independent expert graders. The location, geometry, and imaging characteristic of each druse and SDD was evaluated and depicted in a drusen map of the retina. Furthermore, by utilizing the polarization-sensitive information, the integrity of the associated RPE-Layer was assessed, as well as the presence of pigmentary alterations in the sensory layers of the retina.

Results: : Significantly depending on their size (p<0.05) and shape (p<0.01), 44.4% of all drusen contained depolarizing material, ranging from single core like structures (4,3%) to a complete fill-out with depolarizing material (14.7%). 39% of all drusen had an irregular, but otherwise continuous overlying RPE; in 32% of the drusen, the RPE was disrupted ranging from a small single skip lesion (9.4%) to a complete absence (1.1%). The integrity of the RPE was shown to be significantly correlated with the drusen shape (p<0.01), but not with their size. Pigmentary alterations were found significantly more often above large drusen (p<0.01).

Conclusions: : Polarization-sensitive OCT allows for detailed qualitative evaluation of drusen structures and their associated RPE abnormalities. The relationship between location, size, geometry and type of drusen and the integrity of their overlying RPE is important for further research of patho-mechanisms and therapeutic strategies in the early stages of AMD.

Keywords: drusen • imaging/image analysis: clinical • age-related macular degeneration