Gel injection adjustable keratoplasty.

Gel injection adjustable keratoplasty (GIAK) is a new refractive surgical procedure designed for the correction of myopia by injection of a gel substance into the peripheral corneal stroma. This paper describes the GIAK technique and reports the results obtained in 21 fresh cadaveric eyes using the procedure. After a deep interlamellar canal has been dissected with a helicoid spatula surrounding the visual axis, the gel is injected under keratometric control. In the 1st group of 14 eyes, the degree of correction varied from 2.2 to 12.8 D; there was a direct relationship between the amount of gel injected and the keratometric change. In the 2nd group of 7 eyes, the adjustability of the procedure was demonstrated. Through partial extraction of the gel and subsequent modification of the corneal curvature, the previously induced keratometric changes could be reversed or altered to a specific extent. Following the initial injection of gel to a targeted flattest meridian power of 35 D, an average value of 35.8 +/- 0.5 D was achieved in these eyes. We subsequently attempted to increase the flattest meridian to 40 D by partial removal of the gel and achieved a mean value of 40.2 +/- 0.4 D. Average presurgical astigmatism of 1.497 +/- 0.737 D was reduced to a postsurgical reading of 0.941 +/- 0.590 D (P = 0.005, Student's paired t-test), indicating an autocorrection by autodistribution of the gel inside the canaliculus (Laplace's law). GIAK is a simple, inexpensive procedure designed for the correction of myopia that has the added advantage of reducing preexisting astigmatism without encroaching on the visual axis.