577nm Micropulse Laser vs Half-dose Photodynamic Therapy on Acute Central Serous Chorioretinopathy

Prospective Randomized Controlled Clinical Trial to Evaluate the Effects of 577nm Micropulse Laser vs Half-dose Photodynamic Therapy on Acute Central Serous Chorioretinopathy

The purpose of this study is to determine whether micropulse laser (MPL) is different to half-dose photodynamic therapy on acute central serous chorioretinopathy.

Central serous chorioretinopathy(CSC) is characterized by serous detachment of neurosensory retina which can cause lose in visual acuity.Some studies have shown that Half-dose photodynamic therapy(PDT) is effective on CSC,although accompanied with side-effects,such as choroidal ischemia, retinal pigmental epithelium(RPE) atrophy,and RPE rip,and with exorbitant price.Recent retrospective studies suggest micropulse laser (MPL) therapy may also be effective without obvious complications in this disease. But to date, there is no study on effectiveness of CSC between PDT and MPL. The study is the first prospective randomized controlled trial about 577nm micropulse laser versus half-dose photodynamic therapy on acute central serous chorioretinopathy.The null hypothesis of the study is that there is difference between MPL and half-dose photodynamic therapy on acute central serous chorioretinopathy at first month after treatment.The primary outcome measures is the proportion of eyes with complete absorption of subretinal fluid at 1 month after treatment.

577nm micropulse laser(577-MPL) will be performed of the areas identified on hyperfluorescent "hot spots" on the mid-phase (3 minutes) fluorescein.Multiple laser spots will be applied, covering the leakage area.

Half-dose photodynamic therapy (HD-PDT) is administered to the patients. At 15 minutes after the start of the infusion, PDT laser treatment is performed with standard 50 J/cm2 fluency, a wavelength of 689nm, and a treatment duration of 83 seconds.

All treatments were provided by a single practitioner with the 577-nm yellow laser system(Supra 577nm LaserSystem) in 577-MPL arm. The individual power for the patient was titrated at a normal area of near the affected area in micropulse model.The power titration was started at 700 milliwatt(mW) and then gradually increased until a just visible burn was seen. When this threshold was reached, the power was reduced by 50%, using a 100-μm spot diameter and a 200-ms duration with 5 % duty cycle.

5 minutes after the start of the half-dose verteporfin infusion, the PDT treatment will been performed in HD-PDT arm. The treatment is performed with standard fluency (50 J/cm2), a PDT laser wavelength of 689 nm, and a standard treatment duration of 83 seconds.

The primary outcome measure is the OCT-based improvement rate (defined as the proportion of eyes with complete absorption of subretinal fluid on OCT images

Fundus autofluorescence will be evaluated for different patterns（normal, increased, and decreased）before and after treatment

The outcome measure is the OCT-based improvement rate (defined as the proportion of eyes with complete absorption of subretinal fluid on OCT images

Inclusion Criteria: onset for the first time, as an episode duration of less than 6 months patient was between 18 and 55 years of age the presence of subretinal fluid(SRF) involving the macula and detected by use of optical coherence tomography (OCT) active fluorescein leakage during fluorescein angiography (FA) best corrected visual acuity (BCVA) more than 0.1, and less than 1.0 Exclusion Criteria: previous PDT, focal photocoagulation, intravitreal injections of anti-vascular endothelial growth factor, or ocular surgery other macular abnormalities such as choroidal neovascularization(CNV) or polypoidal choroidal vasculopathy(PCV) retinal atrophy pregnancy inability to obtain photographs or to perform FA use of steroid systemically or topically in the last 6 months