Morphological Characteristics of Idiopathic Juxtafoveolar Teleangiectasia Using Polarization-Sensitive Optical Coherence Tomography

Abstract

Purpose: : Idiopathic parafoveal teleangiectasia (IPT) is a retinal disorder often observed with parafoveal fluid accumulation and hyper-pigmentation. Clinically, patients are often affected by a subtle and progressive loss of central vision. Polarization-sensitive spectral domain optical coherence tomography (PS-SD-OCT) is an extension of optical coherence tomography and allows for imaging the specific polarization properties of the retina and the retinal pigment epithelium (RPE). It is the purpose of this study to examine IPT with latest generation PS-SD-OCT in order to identify disease specific characteristics that might be relevant to understand the pathophysiology of IPT in more detail.

Methods: : 30 eyes of 15 patients with type 2A IPT were examined in a prospective observational case series. A PS-SD-OCT capable of measuring the degree of polarization uniformity (DOPU) of retinal tissue was used in comparison to clinical Spectralis (Heidelberg Engineering) and Cirrus SD-OCT (Carl Zeiss Meditec) devices. Based on the unique property of the RPE to depolarize backscattered light, retinal thickness maps were generated out of PS-SD-OCT datasets and compared to conventional SD-OCT findings. Moreover, PS-SD-OCT data was correlated to autofluorescence and fluorescein angiography images.

Results: : In healthy eyes the RPE is the only structure with depolarizing tissue properties within the retina. However, PS-SD-OCT revealed accumulations of depolarizing tissue (ADT) in the anterior retinal layers in the majority of patients. Based on DOPU images ADT could be segmented with a novel software based algorithm. These lesions can therefore clearly be demarcated in three-dimensional rendering of the data and 2D en-face maps. Small zones of RPE atrophy could be identified marginal to the ADT.

Conclusions: : PS-SD-OCT represents a unique imaging modality to characterize IPT specific findings like the intraretinal ADT. Due to the increased contrast provided by this technique the location and extension of the lesion can be quantified. Focal areas of RPE atrophy may be associated with loss of visual function in patients with IPT.

Keywords: retina • imaging/image analysis: clinical • image processing