Two- and Three-Dimensional Polarization Sensitive Optical Coherence Tomography in Patients With Macular Diseases

Abstract

Purpose:: Evaluation of macular diseases using polarization sensitive optical coherence tomography (PS-OCT) in two- and three-dimensional imaging modes.

Methods:: Two PS-OCT systems were developed and used to image patient eyes with a variety of macular diseases. The first system is based on a transversal scanning time domain approach that provides high-resolution PS-OCT B-scans with a recording time of 0.5s. The second instrument is a high-speed spectral domain PS-OCT system recording 20000 A-lines/s (or a 3D data set in 3s). Both instruments record intensity, retardation, and axis orientation images simultaneously. The data are displayed as high-resolution B-scans, fly-through movies, and volume rendered data sets.

Results:: 30 eyes of patients with a variety of macular diseases were imaged. No mydriasis was necessary to obtain good image quality. The retinal pigment epithelium (RPE) was identified as a polarization scrambling layer (PSL). RPE changes were imaged in eyes with central serous chorioretinopathy and age-related macular degeneration (AMD). The three-dimensional imaging modality allows - based on the absence of the PSL - quantification of the RPE loss in patients with geographic atrophy. Eyes with dry AMD demonstrated in addition polarization scrambling tissue speckles in different retinal layers, potentially an indicator for migrated RPE cells or pigment loaded macrophages. Polarization scrambling tissue speckles were frequently adjacent to zones of RPE atrophy. Characteristic birefringent properties of subretinal fibrosis were evident and quantifiable by PS-OCT.

Conclusions:: PS-OCT provides new qualitative and quantitative information on macular diseases, potentially relevant for diagnosis, prognosis and evaluation of disease progression and new treatment strategies.

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