Intrastromal corneal ring segments (Intacs) are approved by FDA for treatment of low degrees of myopia. Phakic intraocular lens (PIOL) implantation inside the eye can also be used to change refractive errors. The newest type of intervention is a type of PIOL called the implantable collamer lens (ICL) which uses a biocompatible flexible lens which can be inserted in the eye via a 3 mm incision. The ICL is used to correct myopia ranging from −0.5 to −18 diopters, and +0.5 cylinder power to +6.0 for the Toric ICL models. Generally refractive surgery can be broadly divided into: corneal surgery, scleral surgery, lens related surgery (including phakic IOL implantation, clear lens extraction, photophacoreduction and photophacomodulation for correction of presbyopia)
For presbyopia correction, a corneal inlay consisting of a porous black ring surrounding a small clear aperture was originally developed by D. Miller, H. Grey PhD and a group at Acufocus. The inlay is placed under a LASIK flap or in a stromal pocket.Using mid-IR and UV lasers for the treatment of presbyopia by scleral tissue ablation was first proposed and patented by J.T. Lin, Ph.D. in US patents #6,258,082 (in 2001) and #6,824,540 (in 2004). Expectations
Research conducted by the Magill Research Center for Vision Correction, Medical University of South Carolina, showed that the overall patient satisfaction rate after primary LASIK surgery was 95.4%. They further differentiated between myopic LASIK (95.3%) and hyperopic LASIK (96.3%).
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.