Half-dose PDT outperforms subthreshold micropulse laser for central serous chorioretinopathy

Investigators compared the anatomic and functional outcomes of half-dose photodynamic therapy (PDT) versus high-density subthreshold micropulse laser (HSML) in patients with chronic central serous chorioretinopathy (CSC).

Study design

The PLACE trial was an investigator-initiated, open-label, randomized controlled treatment trial conducted at 5 academic medical centers in 4 European countries. Investigators enrolled 179 patients who were randomized 1:1 to PDT or HSML. Patients who demonstrated persistent subretinal fluid (SRF) were retreated with the same initial treatment.

Outcomes

At the first evaluation visit, PDT-treated patients showed higher rates of SRF resolution (51% vs. 14%; P<0.001), better BCVA (+4.6 vs. +1.4 ETDRS letters; P=0.011) and a higher increase in retinal sensitivity on microperimetry (+2.0 vs. +0.9 dB; P=0.046). At the final evaluation visit, PDT treatment sustained higher SRF resolution rates (67% vs. 29%; P<0.001). Improvements in vision-related quality of life was similar between groups (P=0.8).

Limitations

The strengths of the PLACE trial include its prospective design and the relatively large number of patients. Investigators used the complete resolution of SRF on OCT as the desired treatment effect, because the prolonged presence of SRF can cause irreversible photoreceptor damage. Follow-up studies should assess the long-term efficacy of both treatments, particularly given that SRF recurred in 5 patients during the follow-up period.

Clinical significance

This study showed that half-dose PDT is superior to HSML for treating persistent CSC, leading to a significantly higher proportion of patients with complete resolution of SRF and better functional improvement.