Case of the Month I January 2020

The OCT with enhanced depth imaging reveals a thickened choroid in each eye with choroidal pachyvessels (large diameter) in Haller's layer, indicating that the patient has a pachychoroid condition. There is also mild macular edema temporally in the right eye and more substantial macular edema in the left eye. Fluorescein angiography shows window defects and mild late staining, left eye greater than right, without clear leakage. OCTA does not reveal a choroidal neovascular membrane.

This patient's clinical presentation is consistent with chronic central serous chorioretinopathy (CSC). Patients with CSC often have small pigment epithelial detachments and overlying neurosensory detachments, but macular edema can occur. The thickened choroid and pachyvessels are typical of CSC. The window defects on fluorescein angiography likely reflect the disease's chronicity. Patients with CSC often respond favorably to photodynamic therapy (PDT) with Visudyne. This treatment was recently applied to our patient, using half-fluence and avoiding the fovea. PDT is generally effective and is well tolerated by patients with CSC, evidently because the thickened choroid is protective. Patients with thin choroids are more likely to develop ischemic damage from PDT.