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  • Retina/Vitreous

    A randomized controlled study in China found that patients with chronic central serous chorioretinopathy (CSRS) experienced similar 12-month anatomic and functional improvements with either subthreshold micropulse laser therapy (SMLT) or half-dose photodynamic therapy (PDT), although treatment with PDT may offer faster resolution of subretinal fluid (SRF).

    Study Design

    This prospective, double-masked, randomized controlled clinical trial compared outcomes of PDT vs yellow 577 nm SMLT for the treatment of chronic CSCR. Enrolled patients (N = 68) had persistent SRF in the macula for >3 months. Patients were excluded if there was a prior history of macular laser or PDT, concurrent use of steroids, multifocal CSCR, diffuse retinal pigment epitheliopathy, or the presence of choroidal neovascularization or other maculopathy. Randomization was 1:1, and all patients were assessed at baseline and at post-treatment months 1, 3, 6, 9, and 12.


    Of the 61 patients who completed participation in the 12-month study, 91% in the half-dose PDT group (30/33) and 82% in the SMLT group (23/28) had complete resolution of SRF, a nonsignificant difference. There was also no significant difference in recurrence rates between the 2 groups, and both groups demonstrated significant BCVA improvement from baseline. However, patients in the PDT group showed a significantly faster response than those in the SMLT group, with a median time to SRF resolution of 1 month vs 6 months.


    Limitations of this study include the relatively high loss to follow-up in the SMLT group, which was possibly due to a slower response to treatment prompting patients to exit the study and seek other treatment options. In addition, the sample size was too small to assess the safety of the 2 treatments. Exclusion of the more complex cases also affects the generalizability of the study. Finally, the lack of an observation arm limits the understanding of the results to the 2 active treatment arms.

    Clinical Significance

    When comparing half-dose PDT with SMLT, this study suggests that both options are viable but that half-dose PDT may achieve faster anatomic success and functional improvement. Because both laser setups are not performed frequently, and thus may be less accessible than some other treatment options, it is helpful to have more than one active approach to the treatment of CSCR.

    Financial Disclosures: Dr. Lisa Schocket discloses no financial relationships.