Functional and anatomical results of subthreshold micropulse laser as rescue treatment for central serous chorioretinopathy after verteporfin shortage

Background: To evaluate the anatomical and functional outcomes of high-density subthreshold micropulse laser (HSML) treatment in a cohort of patients diagnosed with chronic central serous chorioretinopathy (CSCR) whose treatment with photodynamic therapy (PDT) was delayed due to the worldwide shortage of verteporfin. Methods: Prospective interventional study which included 42 eyes of 40 patients diagnosed with chronic CSCR and on the waiting list for PDT who received rescue therapy with HSML using the Navilas (R) System device (OD-OS GmBH, Teltwo, Germany). Best corrected visual acuity (BCVA), subretinal fluid (SRF), and subfoveal choroidal thickness (SFCT) were measured at inclusion and during the follow-up visits at 2, 4, and 6 months. Results: The mean waiting time from the indication of PDT until treatment with HSML was 14.6 +/- 9.7 months (range 5-21). There were no differences in the pre-treatment BCVA compared with the 6-month follow-up visit (67 +/- 16.7 letters and 67.5 +/- 8.2 letters respectively, p = 0.136). However, there was a significant decrease in the mean SFCT of -39.6 +/- 37.1 mu m (p = 0.030). Additionally, there was a decrease in SRF height between the pre-treatment measure (123.0 +/- 49.8 mu m) and the 2, 4, and 6-month follow-up visits after HSML of -58.5 +/- 68.2 mu m, -53.2 +/- 76.3 mu m, and -65.4 +/- 53.6 mu m respectively (p < 0.001). A complete resolution of the SRF was observed in 16/42 eyes (38.1 %) and a reduction of the SRF height in 85.7 % of the overall cohort was observed after HSML treatment. Conclusion: A significant anatomical improvement in SRF and a decrease in SFCT were observed in patients with CSCR who were previously waiting for PDT and were rescued by HSML. However, the rate of complete SRF resolution was low.