Mechanical methods in refractive corneal surgery.

Over the past decade, keratorefractive surgery has moved into the mainstream of ophthalmology as improved instrumentation and newer techniques have evolved. These new aspects increase the safety and effectiveness of the various keratorefractive procedures. The introduction of new techniques and knife designs has led to improved results with radial keratotomy. The newly developed arcuate keratome purportedly offers the possibility of improving the predictability of arcuate keratotomy. Keratomileusis and epikeratoplasty have been successful for some difficult refractive states, such as aphakia and high myopia. Intracorneal lenses are showing promise in correcting high refractive errors and may offer an alternative to the more technically challenging lamellar procedures performed for correcting these conditions. Intrastromal ring implants are early in their clinical testing, but may provide an alternative to radial keratotomy for correcting myopia. The predictability, effectiveness, safety, and stability are far from perfect for current procedures, but recent results are encouraging.