Central serous retinopathy is a disease of poorly understood etiology characterized by accumulation of subretinal fluid and leading to significant decrease in vision. Micropulse laser therapy has been successfully used in the treatment of CSR of both acute and chronic types (1). In this treatment invisible, non-damaging laser shots are delivered to the affected area which are believed to lead to absorption of accumulated fluid. The mechanism of fluid resorption is unclear. There are several treatment protocols in place (2, 3). Most commonly reported are minimal protocol and so-called panmacular protocol. However, there is no comparative study between them assessing their clinical efficacy.

The purpose of this trial is to compare treatment efficacy in central serous chorioretinopathy (CSR) using two laser parameter settings. Those will include minimal and panmacular protocols. Two wavelengths will be used 577nm and 810 nm for which the rest of the parameters will be defined in order to produce sublethal photostimulation. Structural and functional outcomes will be compared before and after treatment as well as measures such as number of repeat treatments or need for rescue treatment. We aim to show which of the laser arms will lead to better clinical outcomes.

Study Design:

This is a comparative, prospective, interventional, multicenter, randomized study of micropulse laser treatment of central serous chorioretinopathy with 2 treatment arms:

1. < 6 months. Treatment: Minimal vs. Panmacular (randomized)
2. > 6 months. Treatment: Panmacular only

Treatment arms - description of laser settings:

For "Minimal / PLACE" treatment (Mainster contact lens with magnification of 1.05x):

Wavelength 810nm or 577nm, Power 0.75 Watt for 810 nm or 0.15 Watt for 577 nm, Duty Cycle 5% for both wavelenths, Spot size 125um for 810 nm and 100um for 577 nm, Duration 0.3 sec 0.3 sec for both wavelenths, Number of spots 100-120 for both wavelenths

For "Panmacular" treatment (Mainster lens mag 1.05x):

Wavelength 810nm or 577nm, Power 1.70 Watt for 810 nm or 0.425 Watt for 577 nm, Duty Cycle 5% for both wavelenths, Spot size 50um for both wavelengths, Duration 0.3 sec 0.3 sec for both wavelenths, Number of spots 400-450 for both wavelenths

All treatments will be performed following informed consent and under topical anesthesia using eyedrops 3x before procedure in the treatment eye(s). Follow-up will be every 6 weeks with final one in 6 months. Each follow-up visit will include visual acuity measurement, intraocular pressure, slit-lamp examination, VF and OCT examinations.

Primary Endpoints:

1. Visual Acuity as measured by ETRDS chart (number of letters before and after treatment
2. Complete subretinal fluid resolution as assessed by OCT examination (microns of central retinal thickness before and after treatment; presence/absence of subretinal fluid)

Secondary Endpoints:

1. Visual Field - Humphrey 10-2 protocol (dB value before and after treatment)
2. Number of treatments required for vision/structure improvement (number of laser sessions)
3. Rescue rate - number of eyes requiring intravitreal injection of anti-angiogenic agents or oral eplerenone

Risks: Non-response to therapy in which case alternative rescue treatments (intravitreal injection or oral eplerenone) will be offered to patient.

Benefits: Patient participating in the study will receive standard of care. Participation will be entirely voluntary and in case of withdrawing from the study patient will be receiving alternative approved methods of treatment.

Inclusion Criteria:

• CSR diagnosed < 6 months ago Willingness to undergo micropulse laser treatment and keep follow-up visits

Exclusion Criteria:

• High myopia Other significant macular disease, other treatment for CSR Pregnancy

Due to patient confidentiality we do not plan to share individual patient data