Choroidal thickness following extrafoveal photodynamic treatment with verteporfin in patients with central serous chorioretinopathy

Purpose: To evaluate the effect of verteporfin photodynamic treatment (PDT) on choroidal thickness in patients with central serous chorioretinopathy (CSC). Methods: Choroidal thickness was measured with enhanced depth imaging– optical coherence tomography (EDI–OCT) before and after verteporfin PDT (full‐dose verteporfin, half‐light dose) in 16 eyes in 16 patients with serous detachment of the fovea secondary to extrafoveal angiographic fluorescein leakage. Treatment was confined to the area of leakage, whereas choroidal thickness before and after treatment was assessed over a larger area of the fundus using OCT. Results: Complete resolution of the serous detachment was seen in all 16 eyes within 1 month of extrafoveal PDT, while choroidal thickness in the area where PDT was applied decreased from 407 μm [mean; 95% confidence interval (CI₉₅) 356–458 μm] to 349 μm (mean; CI₉₅ 300–399 μm; p < 0.0001), and subfoveal choroidal thickness was reduced from 421 μm (mean; CI₉₅ 352–489 μm) to 346 μm (mean; CI₉₅ 278–414 μm; p = 0.0001). Initially, subfoveal choroidal thickness was significantly increased in the treated eye compared with the healthy fellow eye (mean 324 μm; CI₉₅ 273–376 μm; p = 0.0003), but after treatment, the difference was not significant. Discussion: Photodynamic therapy of active CSC was followed by choroidal thickness reduction, not only locally but also at considerable distance from the treated area. Thus, the process that causes choroidal thickening in CSC appears to spread laterally within the choroid.