Diseases of the Human Macula Investigated With Polarization Sensitive Optical Coherence Tomography

Abstract

Purpose: : To demonstrate the ability of polarization sensitive optical coherence tomography (PS–OCT) to generate a new image contrast in OCT images of different macular diseases.

Methods: : A phase resolved PS–OCT system based on a transversal scanning of the eye was used to image in vivo healthy eyes and eyes of patients with retinal pigment epithelium (RPE) detachment, retinal detachment and RPE atrophy. The instrument measures backscattered intensity, retardation and fast axis orientation, simultaneously and offers a depth resolution of ∼4.5µm within the retina.

Results: : Measurements on healthy eyes showed that light backscattered from a strongly backscattering posterior layer of the retina is depolarized. Images of patients with RPE detachment, retinal detachment and RPE atrophy support a hypothesis that the depolarizing layer can be associated with the RPE. In patients with RPE atrophy an enhanced penetration depth in regions with atrophy into the choroid and sclera is visible. Because of birefringence of the sclera a clear separation between choroid and sclera is visible in PS–OCT images of this region.

Conclusions: : In intensity based OCT images an identification of the RPE (or remnants of the RPE) of diseased eyes is rather difficult. PS–OCT offers an increased image contrast and the depolarization of light backscattered within the RPE can be used to uniquely identify the RPE in PS–OCT images. Furthermore, a differentiation between sclera and choroid due to birefringence of the sclera is visible.

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