Experiments on refractive keratoplasty.

Spectacle correction for eyes with refractive errors is still the most widely used method, but very high-powered spectacle lenses, besides their unpleasing appearance, have the inherent drawbacks of spherical and chromatic aberrations, prismatic effects, and limitation of the visual fields. Contact lenses present their own problems in the form of intolerance, allergy, irritation, and conjunctival and corneal lesions. Several workers have attempted to change the refractive state of the eye by corneal surgery. Barraquer (I949) and Poyales (I950) resected a ring of corneal tissue in the periphery in order to flatten the cornea in high myopes. Barraquer gave the name "refractive keratoplasty" to this procedure. Sato (I955) made multiple radial incisions in the anterior and posterior surface of the cornea, and achieved an improvement ranging from I *5 to 7 dioptres in 72 eyes. Krwawicz (I963) performed partial lamellar resection of the middle layers of the corneal stroma in rabbits without disturbing the anterior or posterior surface. In I964, he performed this operation on three myopic human patients and reported satisfactory results. After several years of laboratory research, Barraquer (i965) described specially prepared lenses of known dioptric power made from homogeneous corneal donor material. These lenses were introduced into an interlamellar pocket of aphakic eyes in order to correct hypermetropia. He termed this procedure "keratophakia". Martinez and Katzin (I965) described other methods and special instruments which could be used to obtain corneal lenses with a positive or negative dioptric power, as desired. Barraquer (I965) described the procedure of "keratomileusis" for the correction of myopia. A lamellar disc is removed from the cornea and after it has been turned on a lathe to change it into a negative lens, it is stitched back onto its bed. The results were satisfactory in twelve human eyes.