Polarisation Sensitive Optical Coherence Tomography Based Detection Of Microexudates In Age-related Macular Degeneration: New Insights In Patho-morphologic Details

Abstract

Purpose: : To evaluate spatial distribution and depolarizing characteristics of retinal microexudates (ME) in age-related macular degeneration (AMD) using spectral domain optical coherence tomography (SD-OCT) and polarization sensitive optical coherence tomography (PS-OCT).

Methods: : In this cross-sectional study, 20 eyes with exudative AMD were examined using color fundus photography (CFP), SD-OCT and PS-OCT. Images were reviewed by a masked investigator regarding the intraretinal localization, distribution and depolarizing status of retinal microexudates.

Results: : In all eyes, mircoexudates detected by SD-OCT and PS-OCT distributed throughout all retinal layers, but most prominently at the border of the outer nuclear layer (ONL) and the inner segment/outer segment layer (IS/OS). With color fundus photography MEs were undetectable, however conglomerated MEs forming clinically significant hard exudates were detectable. On PS-OCT not all microexudates showed depolarizing characteristics.

Conclusions: : This study showed that microexudates in AMD could be detected by SD-OCT and PS-OCT but not on color fundus photography. Although on SD-OCT all mircoexudates looked similar PS-OCT showed that they differ in their depolarizing quality, implying that ME form a heterogeneous group. Further investigations are necessary to clarify the dynamics of ME distribution over time. PS-OCT is a valuable device to examine and quantify microexudates.

Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)