High Definition Optical Coherence Tomography in Central Serous Chorioretinopathy

Abstract

Purpose:: Conventional optical coherence tomography (OCT) has brought new insights into chorioretinal pathologies. However, OCT is restricted due to its low scanning speed and limited resolution especially when discrete changes have to be evaluated.High definition raster scanning OCT (HD-OCT) was used to elucidate the pathophysiology in patients with central serous chorioretinopathy (CSR). New morphologic features could be presented.

Methods:: 30 eyes of 30 patients with subretinal fluid accumulation due to CSR were imaged using a high-speed frequency-domain high-resolution optical coherence tomography device (Prototype of Cirrus^TM HD-OCT) with an axial image resolution of 6 µm and up to 20 k A-scans/second resulting in a 128x512x1024 volume block as well as ultra high resolution images. A volume of 5.8x5.8 mm and a depth-range of 2 mm were examined in the macular retina. Two-dimensional quasi- histologic section analysis and three-dimensional reconstruction were performed.

Results:: Detailed information about layer-specific distribution of fluid accumulation can be obtained in all compartments, i.e. intra-, subretinally and sub-pigmentepithelially.Discrete changes in reflectivity are visualized within the outer nuclear/plexiform layers in more than 90 % of all patients. Subretinal fluid appears as a dome-shaped, well demarcated fluid pooling and is not associated with a loss of photoreceptor layer integrity. Deposits are demarcated underneath the outer cone segments in detached neurosensory retina. Multiple small pigment-epithelial detachments (PED) can be seen in 63% of patients. Their exact configuration is demonstrated topographically using semi-automated high end rendering software analysis.

Conclusions:: HD-OCT provides extensive information regarding precise topographic and layer-specific localization of morphologic changes. Exact volumetric quantification of subretinal fluid and pigment epithelial deviations become accessible. An Identification of pathology related structural changes of the neurosensory retina might help to get new insights into pathogenesis of chorioretinal disease. Concluding, HD-OCT improves the clinical evaluation and monitoring of disease progression.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal pigment epithelium • photoreceptors