Until the time , low threshold diode laser came into use by Dr. Agarwal Hospitals, Retinal laser meant for laser to be used on the retina to make photocoagulation marks that meant using higher wattage and duration of dode laser 810 nanometer wavelength
When this machine came under Dr. Agarwals usage she brought the size, duration and wattage to less than 1/20th the original amount that would create a burn on the retina. The argument then was and still is, that the retina needs only to be stimulated by this wavelength and not burnt.
This would create a photochemical change on a biochemical level and not need to actually burn the retina. The efficacy of the retinal laser treatment was in making sure there was no bleeding on diabetic eyes or damaged blood vessels.