Subthreshold Micropulse Laser Therapy (SML) in Retinitis Pigmentosa

"A 577 nm yellow and 810 nm red lasers will be used for stimulation. The panmacular stimulation is planned, with the laser covering the entire central retina between the vascular arches, including the foveal region according to the study protocol.~Patient preparation will include obtaining informed consent, local anesthesia of the conjunctival sac with 0.05% proxymetacaine drops to reduce discomfort, and the administration of 0.1% tropicamide to dilate the pupil and increase access to the retina during laser stimulation. Next, a Volk macular contact lens (Volk Optical, Mentor, OH, USA) will be placed on the cornea using a viscoelastic agent. A modern 577 nm yellow laser (Supra Scan 577, Quantel Medical, Cedex, France) will be used for stimulation. The panmacular stimulation is planned, with the laser covering the entire central retinal area between the vascular arches, including the foveal region."

Preparation for SML using an 810 nm red laser will involve informed consent, local anesthesia of the conjunctival sac with 0.05% proxymetacaine drops to reduce discomfort during the procedure, and the administration of 0.1% tropicamide to dilate the pupil and increase access to the retina during laser stimulation. A Volk macular contact lens (Volk Optical, Mentor, OH, USA) will then be placed on the cornea using a viscoelastic agent. Central retinal stimulation will be performed using an 810 nm SML. The panmacular stimulation protocol will be used, with the laser covering the entire central retinal area between the vascular arcs, including the foveal region. During one session, approximately 1500-2000 confluent local applications of 200 μm diameter will be performed using 1.4 W of power with a duration of 0.15 seconds and a 5% duty cycle.

It is worth emphasizing that the experiment was designed as a factorial study design with the patient blinded. To this end, patient preparation, laser treatment duration, and auditory and visual sensations during the sham procedure will be the same as those experienced with a truly lasered eye. Consequently, fellow eye of an each RP eye that undergone the SML stimulation in either arm 1 or 2 will be included in the sham group (60 eyes).