Use of spectral-domain optical coherence tomography to observe the RPE-Bruch's membrane-choriocapillaris complex in central serous chorioretinopathy

Abstract

Objective To investigate the imaging features of the retinal pigment epithelium (RPE)-Bruch's membrane (BM)-choriocapillaris complex in central serous chorioretinopathy (CSC) with spectral-domain optical coherence tomography (Spectralis OCT). Methods This was a noninterventional, observational study. One hundred and eleven eyes of 109 consecutive patients (male 89, female 20) diagnosed with CSC were included. All the patients underwent a full ophthalmologic examination, including the visual acuity, slit-lamp microscope, pre-set lens, fundus photography, Spectralis OCT and fundus fluorescein angiography (FFA). Indocyanine green angiography (ICGA) was performed on some patients. The RPE-BM-choriocapillaris complex, which manifested as a high-reflecting band in Spectralis OCT, was carefully checked. Based on the visibility of BM, it was classified into two types: a visible type or invisible type. The visible type was then classified into an obvious type or occult type. If visible, BM appears thinner and more reflective than the RPE-BM-choriocapillaris complex. Meantime, the pigment epithelial detachment (PED) was classified into different types corresponding to the BM categories. The number of different categories were counted, measured and recorded as percentages. Results The visualization of BM manifested in all 11 eyes (100%), but differed to the extent for which it was visible. Of the 111 eyes, the BM was obvious in 99 eyes (89.8%). In the other 12 eyes (10.2%) it was difficult to discriminate, but there were still distinguishable differences from normal RPE-BM-choriocapillaris complexes. The visualization of BM was more obvious and wider in the 27 chronic CSC eyes than in the 84 acute CSC eyes when accompanied by the atrophy of choriocapillaris and RPE. BM was discriminated or visualized at all of the tracking leakage points demonstrated on FFA images. Conclusion BM is sandwiched between the RPE and choriocapillaris, and it cannot be distinguished in the normal high-reflecting band of the complex in a Spectralis OCT image. Visualization of BM in the RPE-BM-choriocapillaris complex demonstrates a detachment not only between BM and the RPE, but also perhaps between BM and the choriocapillaris. This discovery may offer new morphological and pathological evidence for central serous chorioretinopathy. Key words: Tomography,optical coherence; Chorioretinis,serous,central; Retinal detachment; Bruch's membrane; Capillaris,choroid