الفهرس 
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Abstract
Aim of the work
The aim of this essay is to review the literatures for methods of presbyopic correction including surgical and non surgical techniques.
Summary
The condition of presbyopia can be compensated for by many methods NON SURGICAL in which we use corrective plus lenses including:
1) EYEGLASSES
Presbyopia can be corrected easily by a single pair of glasses in emmetropes. And two pairs of glasses one for distance and the other for near in presbyopes with error of refraction. Another option is multifocal lenses (Michael and Benjamin, 1998).
2)CONTACT LENSES
In order to reduce the need for bifocals or reading glasses, some people choose contact lenses to correct one eye for near and one eye for far with a method called ”monovision”. Monovision sometimes interferes with depth perception.
(Mackie, 1993).
And SURGICAL there are basically three methods to correct presbyopia (Agarwal, 2002).
1) SCLERAL SURGERY
I-Scleral Expantion Bands
By using four pieces of polymethylmethacrylate (PMMA) implanted in a tunnel in the sclera to increase the space between the ciliary body and lens.
The major complications of such procedure include:
-Scleral bands subluxation
-Scleral bands rotation
-Conjunctival erosion
-Anterior Ischemic Scleritis
-Endophthalmitis.
-Scleral Thinning. (Cross and Zdenek, 2006)
II-Anterior Ciliary Sclerotomy
Using the Thornton Triple Edge diamond knife (Mastel-KOI, T–2241) to obtain 95%scleral thickness incisions, Initial results were encouraging but limited.
The major complications of such procedure include:
-Infection.
-Hemorrhage (from cutting too deep).
-Ocular hypotension.
-Myopic shift.
-Perforation (Fukasaku H, 2000).
III-Laser Treatment
Er: YAG laser can successfully create well defined incisions in sclera overlaying the ciliary body without causing noticeable inflammatory changes, anterior segment damage, or collateral damage to tissue underlying the laser incisions. (Mammalis, 2002).
2) CORNEAL SURGERY
I-Intracorneal Inlay Lenses
By creating a bifocal cornea when a small diameter intra-corneal inlay lens is implanted into the optical zone of the cornea, it produces a higher refractive power due to the lens design and power (Lindstorm, 1996).
The major complications of such procedure include:
-Decenteration
-Small loss of contrast sensitivity, or quality of distant vision.
-Astigmatism.
-Mild night vision symptoms, primaliry halos.
-Interface problem and flap complications.
-Extrusion of the lens.
-Infection.
-Epithelial opacification. (Alio et al, 2004)
II-Monovision
III-Presbyopic Lasik
In these procedures, the surgeons attempt to reshape the corneal surface so there may be different regions within the cornea that have different powers. This allows simultaneous vision at distance through the flatter part of the cornea and at near through the steeper part of the cornea.
1- Excimer presbyopic correction:
-PhotoRefratctive Keratectomy (PRK).
-Presbyopic Lasik. 2- ThermoKeratoplasty Techniques:
-Radial ThermoKeratoplasty (RTK).
-Laser ThermoKeratoplasty (LTK).
IV-Conductive Keratoplasty
Conductive Keratoplasty (CK) is a non-laser, radiofrequency-based procedure for treating presbyopia depending on high frequency energy delivered into the stroma with a specially designed contact probe. The temperature and duration of radiofrequency energy applied by the probe is optimal for collagen shrinkage without necrosis.
New Ideas Corneal Surgery:
-Solid State Lasers for Refractive Surgery.
-The Femtosecond Laser.
-Corneal Biomechanics Custamization.
3-IOLs:
I-Multifocal Implant
The loss of the accommodative ability following cataract surgery has been overcome to an extent by the development of intraocular lenses with multifocal optics. (Montes-Mico and Alio, 2003).
The different types of multifocals are the diffractive type, the refractive asphcric type, and the two or three zone refractive type
II-Accommodative IOLs
Certain newer types of IOLs have been developed that take into account the normal physiological interplay of ciliary body with the crystalline lens. They transform the contracting forces of ciliary muscle into anterior movement of the IOL optic (Humming et al, 2001).
III-Presbyopic phakic implants
With many advances:
-The Vision Membrane
-Flexible polymers:
Designed for injection into a nearly intact capsular bag (Nishi and Nishi, 1998)
-The Smart Lens:
It is a thermoplastic acrylic gel, shaped into a thin rod and inserted into the capsular bag.
-Femtosecond Lentotomy:
It involves creation of intralenticular incisions which result in additional gliding planes within the lens substance, thereby increasing its flexibility. (Gerten, 2007).