Short term choroidal microvascular changes following photodynamic therapy in chronic central serous chorioretinopathy

Background: Central serous chorioretinopathy (CSC) is characterized by focal serous detachment of the retina, primarily affecting the macula. Photodynamic therapy (PDT) is the best choice for treatment of chronic and recurrent patients. In this study we aim to evaluate the early effects of the half dose protocol (3 mg/m2 verteporfine) of PDT laser treatment on the micro vasculature of choroid.Methods: Among thirty-one patients (62 eyes), twenty eyes were in the control group and forty-two eyes received PDT laser treatment. Vision log MAR, CMT (central macular thickness), SRF (sub retinal fluid), BCT (baseline choroidal thickness), CVI (choroidal vascular index), and laser treated area were compared between two groups. Results: Results show that no strong correlation was detected between the impact of laser treatment and resolution of SRF in the first week in the fovea. The mean best corrected visual acuity (BCVA) of the patients significantly increased from 20/63 at the beginning of the study, according to the Snellen chart, to 20/49 in the first week and 20/38 in the sixth week. PDT can significantly reduce SRF and CMT in 6 weeks compared to the control group. Although there was initially a small, non-statistically significant increase in choroidal thickness and CVI after 1 week, a dramatic decrease occurs after 6 weeks. Therefore, after 6 weeks of PDT laser, all the indicators such as SRF, CMT, choroidal thickness, and CVI significantly reduced. Conclusion: PDT laser can significantly reduce SRF and CMT at 1 and 6 weeks and choroidal thickness and CVI at 6 weeks in chronic CSC patients. Also, a larger laser treated area has no impact on the final outcome. Therefore, it seems that the mechanism of PDT in CSC disease is the recovery of choriocapillaris circulation.