الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 127 |  |  |
| | | from | 127 | | |
Abstract
Although, glasses and contact lenses offer individuals a readily available method of correcting refractive errors, many problems face the use of them making us to choose the refractive surgery over contact lenses and glasses. Patients with a specific activity, patients with medical problems that might increase the risk of wearing contact lenses, patients who are unable or not willing to participate inappropriate lens care and follow-up care, patients who are unable to learn to insert and remove contact lenses or do not have a family member who can assist with this process, and patients who may have poor hygiene, should be considered as a category looking for the surgical correction. Unlike myopes, hyperopes may have difficulties with visualization of contact lenses during handling, since these patients do not have any near point in focus. High-powered convex lenses create cosmotic problems. Altered depth perception and difficulty with hand-eye coordination are exampies for the problems of correcting of hyperopia with high-plus powered spectacle lenses resulting from magnification.
Refractive surgery may be the first option for some patients with certain specific conditions. For example, refractive surgery is the choice in cases of symptomatic anisometropia. The mainstay of treatment of refractive accommodative esotropia is the correction of the hyperopic refractive error especially by the surgical alternatives for the correction of hyperopia.
In the history of surgical correction, there have been several methods that are no longer popular. One technology was keratomileusis. In order to minimize the complexity of the procedure, a donor disk is also used. This is called keratophakia. Hexagonal keratotomy is another refractive procedure formerly employed for hyperopia. The procedure consists of making a series of paracentral incisions in a hexagonal pattern with subsequent steepening of the central cornea. This procedure was later found to frequently be associated with glare, photophobia, fluctuating vision, and irregular astigmatism. Thus, this technique was abandoned. Predictability was not adequate. Automated lamellar keratoplasty is another method for the correction of hyperopia. Progressive ectasia in a significant percentage of eyes renders this technique unattractive.
Current options used in correction of hyperopia include:
1. Excimer laser procedures:
- Laser in situ keratomileusis. (LASIK): up to +6 D.
- Surface ablation. (PRK, LASEK, Epi-LASIK): up to +6 D.
2. Collagen shrinkage procedures:
- Conductive keratoplasty: up to +3 D. with regression.
3. Corneal implants:
- Intracorneal peripheral segments. (ICS): up to +2 D.
4. Clear lens extraction with IOL implantation: (Clear lens exchange)
- Piggyback implantation: increases the range of hyperopic correction more than +8 D.
5. Phakic intraocular lenses: available powers are up to +21.5 D.
- Anterior chamber PIOL. :
• Angle supported.
• Iris claw.
• Posterior chamber PIOL.