Micropulse Laser, Half-Dose Photodynamic Therapy Deliver Comparable Results in CSCR

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Eye Laser Surgery, Refractive eye surgery at the Adolphe de Rothschild Ophthalmology Foundation in Paris, Eye surgery using a femtosecond laser and excimer laser. The femtosecond laser slices the cornea to create a corneal cap (purple) then the surgeon lifts the flap to treat the eye with the excimer laser. The cornea flap is then put back in place without stitches. This technique is used to treat myopia, presbyopia, astigmatism and farsightedness. Post-op check-up. (Photo by: BSIP/Universal Images Group via Getty Images)
With limited access to PDT, researchers believe the micropulse laser provides equivalent treatments.

Half-dose photodynamic therapy (PDT) and subthreshold micropulse laser have both shown effectiveness in reducing subretinal fluid and improving visual acuity for patients with central serous chorioretinopathy (CSCR), but up until now the 2 treatment options have not been widely tested head-to-head. This may be an important point, because half-dose PDT is not currently available in many regions.

Investigators recruited 39 participants, average age 43.4 years, with new-onset CSCR, and established 2 groups: 21 eyes to be treated with half-dose PDT, and 18 who would receive subthreshold micropulse laser photocoagulation, according to an article published in March by BMC Ophthalmology. Participants were at least 18 years of age with symptoms for 3 months or less, displayed foveal subretinal fluid with or without RPE detachment, and presented active leakage. The follow-up period was 12 months.

Results of this investigation demonstrated no significant difference between groups for percentage of eyes with reabsorption of macular subretinal fluid (P =.647), or number of treatments needed during the study period (P =.174). The proportion of eyes with complete reabsorption fluctuated between 3 and 9 months, potentially due to recurrences. So far, previous research has reported conflicting results for whether subthreshold micropulse can prevent return of CSCR.

In the micropulse cohort, SRF was reabsorbed in 61.1% of eyes by 1 month, 83.3% at 3 months, 66.7% in 6 months, 88.89% at 9 months, and 83.3% by 12 months. Three patients experienced fluid recurrences and 2 had persistent SRF. Alternately, in the half-dose PDT group, SRF resolved for 81.0% of eyes by 1 month, 95.2% at 3 months, 90.5% in 6 months, 85.71% at 9 months, and 90.5% by 12 months. Fluid returned for 2 participants receiving half-dose PDT and 1 displayed persistent SRF.

There were also no significant differences between the two therapies regarding BCVA at 1 month (P =.610), 3 months (P =.537), 6 months (P =.304), 9 months (P =.993), and 12 months (P =.731). Similarly, results were comparable for retinal sensitivity — assessed in a dark room with microperimetry, measured inside 12 degrees of retinal center. 

The analysis notes that both groups experienced significant improvements in mean retinal sensitivity at each visit after treatment compared with baseline, and that the retinal sensitivity was slightly better in the half-PDT group than the subthreshold micropulse group at the final visit; however, there was no statistical difference between the 2 groups.

In this study, no systemic or local therapy-related adverse events occurred. Limitations of the analysis include a small sample size, as well as a retrospective, nonrandomized design without an untreated control group. In a majority of cases, CSCR resolves on its own, but as much as 30% to 50% of patients have a recurrence of symptoms indicating serous retinal detachment during the first year. 


Zeng M, Chen X, Song Y, Cai C. Subthreshold micropulse laser photocoagulation versus half-dos photodynamic therapy for acute central serous chorioretinopathy. BMC Ophthalmology. Published online March 8, 2022. doi:10.1186/s12886-022-02331-z