[Evaluation of the choroid in central serous chorioretinopathy]

Studies using indocyanine green angiography (ICGA) revealed that the main cause of central serous chorioretionopathy (CSC) stems from choroidal abnormalities such as choroidal vascular hyperpermeability. However, there are no methods to evaluate the choroid except for either the invasive ICGA or low-resolution ultrasonography. The recently developed enhanced depth imaging optical coherence tomography (EDI-OCT) technique can visualize the choroid appropriately and noninvasively using conventional OCT. EDI-OCT showed that both the affected and unaffected eyes in CSC patients have a thickened choroid; whereas the remarkably thickened choroid in Vogt-Koyanagi-Harada disease decreases immediately after corticosteroid treatment and the eyes with high myopia show a thinner choroid. We evaluated the choroidal thickness after treatment of CSC. The subfoveal choroidal thickness in typical CSC treated with laser photocoagulation showed no changes during the follow-up. On the other hand, the subfoveal choroid in chronic CSC treated with half-dose verteporfin photodynamic therapy (PDT) showed temporary thickening after 2 days but thinned back 1 month after treatment. Both the choroidal thickness and choroidal vascular hyperpermeability in ICGA decreased after PDT, but they did not change after laser photocoagulation. These findings suggest that PDT can affect the abnormal choroid directly and works through a different mechanism from conventional laser photocoagulation. It is important to evaluate the choroid using OCT in CSC and other macular diseases.