Abstract
Purpose: :
To study morphological change of choroid that related to fluid leakage through the retinal pigment epithelium (RPE) in central serous chorioretinopathy (CSC).
Methods: :
Fifty-six eyes 55 patients with CSC were examined with Spectralis OCT (Heidelberg, Germany) by using enhanced depth imaging (EDI) that facilitate to investigate choroidal structure. The EDI-OCT images of the area around fluorescence leakage points were compared with the angiographic findings after magnifying (4x) and adjusting the levels of histograms of an EDI-OCT image by using imaging computer software. Routine ophthalmological examination including visual acuity, fluorescein and indocyanine green angiography (IA) was performed for all patients.
Results: :
EDI-OCT delineated a section image of a lobules of choriocapillaris as the layer of high signal intensity beneath the RPE. Choriocapillaris was connected to large choroidal vessels by pre- or post capillary vessels about 20 microns in diameter. Small choroidal vessels about 50-100 microns in diameter aligned with periodicity beneath the layer of choriocapillaris. The high signal intensity layer of choriocapillaris was narrowing (23 eyes, 41%) or interrupted (33 eyes, 59%) around leakage points. ‘Narrowing’ and ‘interrupted’ were defined as the lesion over 200 microns in length. In this area, small choroidal vessels shifted anterior. These findings corresponded hypofluorescent spots on IA appeared around the leakage point surrounded by extensive diffuse hyperautofluorescence in 54 (96%) eyes.
Conclusions: :
Narrowing or interruption of the choriocapillaris and anterior shift of small choroidal vessels imply collapse or closure of the choriocapillaris around the leakage points because these findings appeared in the area showing hypofluorescence in IA. The circulatory disturbance of choriocapillaris may cause hyperpermeability in the surrounding area as a result of turbulence of blood flow, which was shown in IA. Failure of choriocapillaris inducing capillary occlusion is potentially the primary lesion of CSC.
Keywords: choroid • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)