Enface Features of Chronic Central Serous Chorioretinopathy on Swept-Source Optical Coherence Tomography

Abstract

Purpose: To characterize enface features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR), using a novel swept-source optical coherence tomography (SS-OCT) prototype.

Methods: Consecutive eyes with the clinical diagnosis of chronic CSCR were prospectively examined with a SS-OCT system operating at 1050nm wavelength and 100,000 A-lines/sec with 6µm axial resolution. Multiple 3D 6x6mm macular cube raster scans were obtained, processed with software for motion correction and merged to increase signal. Segmentation of the RPE was performed to generate a reference surface and enface OCT images of the RPE and choroid were extracted at varying depths every 4µm (1pixel) from the RPE/Bruch’s Membrane complex to the sclera. Atypical features on the enface images were characterized by systematic analysis of multimodal fundus imaging records including color photographs, fundus autofluorescence, and fluorescein and indocyanine-green angiography (ICGA). The study was performed under approved IRB protocols from the New England Eye Center and Massachusetts Institute of Technology.

Results: Seven patients (9 eyes) were enrolled in the study; 6 males; mean age 49.8 years (±8.8 years); BCVA ranged from 20/20 to 20/200. Enface OCT images at the RPE level revealed specific changes in SS-OCT signal in all eyes; absence of signal corresponding to RPE detachment and increased signal corresponding to RPE split . Enface OCT images of the choroid suggested dilation of medium and large choroidal vessels, either focal (28% of eyes) or diffuse (57% eyes) , underlying RPE changes. No inferences could be made about the choriocapillaris layer, although enface images at this level revealed choroidal neovascularization in one eye, classified on ICGA as polypoidal choroidal vasculopathy. Enface images clearly documented the neovascular membrane, while ICGA highlighted only polypoidal terminations .

Conclusions: High-speed, SS-OCT at 1050nm wavelength enables the characterization of pathological features of the RPE and choroid in eyes with chronic CSCR. Enface OCT imaging appears to be a valuable tool in the identification of choroidal neovascularization. This in vivo documentation of the RPE and choroidal vasculature in variable depths may lead to physiopathological inferences and is potentially valuable in the diagnosis and management of chronic CSCR.

Keywords: 550 imaging/image analysis: clinical • 701 retinal pigment epithelium • 452 choroid