Structural Changes of Inner and Outer Choroid in Central Serous Chorioretinopathy Determined by Optical Coherence Tomography

PURPOSE: To determine the structural changes of the choroid in eyes with central serous chorioretinopathy (CSC) by enhanced depth imaging optical coherence tomography (EDI-OCT). METHODS: A retrospective comparative study was performed at two academic institutions. Forty eyes with CSC, their fellow eyes, and 40 eyes of age-matched controls were studied. Subfoveal cross sectional EDI-OCT images were recorded, and the hypo reflective and hyperreflective areas of the inner and outer choroid in the EDI-OCT images were separately measured. The images were analyzed by a binarization method to determine the sizes of the hyporeflective and hyperreflective areas. RESULTS: In the inner choroid, the hyperreflective area was significantly larger in the CSC eyes (35,640±10,229 μm(2)) than the fellow eyes (22,908±8,522 μm(2)) and the control eyes (20,630±8,128 μm(2); P<0.01 vs control for both, Wilcoxon signed-rank test). In the outer choroid, the hyporeflective area was significantly larger in the CSC eyes (446,549±121,214 μm(2)) than the control eyes (235,680±97,352 μm(2), P<0.01). The average ratio of the hyporeflective area to the total choroidal area was smaller in the CSC eyes (67.0%) than the fellow eyes (76.5%) and the control eyes (76.7%) in the inner choroid (P<0.01, both). However, the ratio was larger in the CSC eyes (75.2%) and fellow eyes (71.7%) than in the control eyes (64.7%) in the outer choroid (P<0.01, both). CONCLUSIONS: The larger hyperreflective area in the inner choroid is related to the inflammation and edema of the stroma of the choroid in the acute stage of CSC. The larger hyporeflective areas in the outer choroid is due to a dilatation of the vascular lumens of the larger blood vessels. These are the essential characteristics of eyes with CSC regardless of the onset.