A pilot prospective study of 577-nm yellow subthreshold micropulse laser treatment with two different power settings for acute central serous chorioretinopathy

To compare the efficacy of 50% threshold power with 25% threshold power of 577-nm subthreshold micropulse laser (SMPL) for acute central serous chorioretinopathy (CSC). Prospective, interventional, non-randomized, comparative case series. A total of 54 patients (54 eyes) with acute CSC were enrolled. Twenty-four eyes received 25% threshold power and 30 eyes received 50% threshold power of 577-nm SMPL. Best-corrected visual acuity (BCVA), central macular thickness (CMT), and complete absorption of subretinal fluid (SRF) were evaluated at 1 month and 3 months. The complete absorption rate of SRF in the 50% power group was significantly greater than that in the 25% power group at 1 month (70.0% vs 25.0%, p < 0.001) and at 3 months (83.3% vs 54.2%, p < 0.001). Mean BCVA improved from 0.34 +/- 0.20 LogMAR to 0.02 +/- 0.13 LogMAR in the 50% power group and from 0.27 +/- 0.15 LogMAR to 0.14 +/- 0.21 LogMAR in the 25% power group with a significant difference between the two groups after 3 months (p = 0.027). In the 50% power group, the CMT decreased from 491.6 +/- 154.8 mu m at baseline to 231.3 +/- 92.3 mu m at 1 month and 228.2 +/- 88.1 mu m at 3 months, and in the 25% power group, the CMT decreased from 444.9 +/- 164.1 to 306.8 +/- 102.6 mu m at 1 month and 254.5 +/- 101.7 mu m at 3 months. There was statistical difference of CMT at 1 month (p = 0.009) but no significant difference at 3 months between the two groups (p = 0.232). SMPL with 50% threshold power may be more effective than 25% threshold power for acute CSC.