Lasers revolutionized medicine, particularly in two specialties where the organ is accessible to light: dermatology and ophthalmology. We use : - excimer laser (UV) for their photoablative properties, to change to anterior corneal radius of curvature in refractive surgery (fun fact: the first attempt to use this laser was pure serendipity : "oh I got this excimer in my lab, here is a chicken sandwich, let's see what is gives on organic tissues") - ND:Yag laser to pierce a small hole in the iris when it is necessary to establish a communication, or to locally break the posterior lens capsule when it opacifies after cataract surgery ; those two procedures where far from benign when they had to be performed surgically , today it is made in the office in a few seconds - femtosecond lasers to cut a thin layer of cornea , which is lifted , before applying the excimer laser, in LASIK procedures - diode lasers to reduce the intraocular pressure by destroying parts of the ciliary body in very specific cases - various lasers to photocoagulate lesions on the retina....

Ophthalmology without lasers would look like a middle-ages practice.