# Comparative efficacy of half-dose and one-third-dose photodynamic therapy in chronic central serous chorioretinopathy: a retrospective study

## TL;DR

This study compares two lower-dose photodynamic therapies for chronic central serous chorioretinopathy and finds that the half-dose treatment is more effective in resolving fluid and improving vision.

## Contribution

The study provides new evidence that half-dose photodynamic therapy is more effective than one-third-dose for chronic central serous chorioretinopathy.

## Key findings

- Half-dose PDT achieved higher complete subretinal fluid resolution (78.4%) compared to one-third-dose (71.4%).
- Half-dose PDT had a significantly lower recurrence rate (7.5%) than one-third-dose (20%).
- Half-dose PDT resulted in greater visual acuity improvement (52% with ≥10-letter gain) compared to one-third-dose (28.5%).

## Abstract

To compare the efficacy and safety of half-dose and one-third-dose photodynamic therapy (PDT) with verteporfin in patients with chronic central serous chorioretinopathy (CSC).

This retrospective study included 72 eyes from 72 patients with chronic CSC treated with either one-third-dose (2 mg/m²) or half-dose (3 mg/m²) PDT. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), subretinal fluid (SRF) thickness, subfoveal choroidal thickness (SFCT), and optical coherence tomography (OCT) features were evaluated at baseline, 3 months, and 12 months. Fluorescein angiography (FA) was used to guide laser application. Treatment outcomes, including SRF resolution, BCVA gain, and recurrence rates, were compared between the two groups.

At 12 months, complete SRF resolution was achieved in 40 eyes (78.4%) in the half-dose group and 15 eyes (71.4%) in the one-third-dose group. The recurrence rate of SRF was significantly higher in the one-third-dose group (20%) compared to the half-dose group (7.5%) (P =.015). BCVA improved significantly in both groups, with mean increases from 72.4 ± 3.9 to 77.1 ± 5.6 letters in the one-third-dose group and from 74.4 ± 4.2 to 80.2 ± 2.19 letters in the half-dose group. The proportion of patients achieving a ≥ 10-letter gain was higher in the half-dose group (52%) compared to the one-third-dose group (28.5%, P =.001). Both groups exhibited significant reductions in CRT, SRF thickness, and SFCT (P <.001), with no significant intergroup differences. Baseline CRT and fluorescein leakage patterns influenced treatment response.

Both one-third-dose and half-dose PDT effectively improved visual and anatomical outcomes in patients with chronic CSC. However, half-dose PDT demonstrated superior efficacy in achieving SRF resolution and greater visual acuity gains with a lower recurrence rate.

Not applicable.