Refractive eye surgery is optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileusis), lens implantation or lens replacement. The most common methods today use excimer lasers to reshape the curvature of the cornea. Refractive eye surgeries are used to treat common vision disorders such as myopia, hyperopia, presbyopia and astigmatism. History
The first theoretical work on the potential of refractive surgery was published in 1885 by Hjalmar August Schiøtz, an ophthalmologist from Norway. In 1930, the Japanese ophthalmologist Tsutomu Sato made the first attempts at performing this kind of surgery, hoping to correct the vision of military pilots. His approach was to make radial cuts in the cornea, correcting effects by up to 6 diopters. The procedure unfortunately produced a high rate of corneal degeneration, however, and was soon rejected by the medical community. The first proficient refractive surgery technique was developed in the Barraquer ophthalmologic clinic (Bogotá, Colombia), in 1963, by Jose Barraquer. His technique, called keratomileusis, meaning corneal reshaping (from Greek κέρας (kéras: horn) and σμίλευσις (smileusis: carving)), enabled the correction, not only of myopia, but also of hyperopia. It involves removing a corneal layer, freezing it so that it could be manually sculpted into the required shape, and finally reimplanting the reshaped layer into the eye. In 1980, Swinger performed first keratomileusis surgery in US.
With procedures that create a permanent flap in the cornea (such as LASIK), there is also the possibility of accidental traumatic flap displacement years after the surgery, with potentially disastrous results if not given prompt medical attention.For patients with strabismus, risks of complications such as diplopia and/or increased strabismus angle need to be evaluated carefully. In case both refractive surgery and strabismus surgery are to be performed, it is recommended that the refractive surgery be done first. Children
Pediatric refractive surgery involves other risks than refractive surgery on adults, yet it may be indicated especially for children whose cognitive or visual development is failing due to refractive error, in particular in cases of bilateral high refractive error, anisometropia, anisometric amblyopia or accommodative esotropia.Interventions on young children may require general anaesthesia in order to avoid risks due to involuntary movement, and children have a higher risk of rubbing or manipulating their eyes post-surgically. Changes to refractive error occurring during normal age development need to be accounted for, and children have a higher risk of developing postoperative corneal haze. This risk is particularly relevant with relation to myopic children.One study evaluated the outcome of LASEK interventions on 53 children aged 10 months to 16 years who had anisometropic amblyopia. The choice of LASEK was made as it was felt it would give fewer complications than LASIK and less post-operative pain than PRK. In the intervention, which was performed under general anaesthesia, the refractive error in the weaker eye was corrected to balance the refractive error of the other eye.