Developments in the correction of presbyopia II: surgical approaches.
OBJECTIVE
To discuss the various static and dynamic surgical approaches which attempt to give presbyopes good vision at far, intermediate and near viewing distances.


BACKGROUND
Static methods broadly adopt the same optical techniques as those used in presbyopic contact lens correction and aim to satisfy the needs of the presbyope by increasing binocular depth-of-focus, often using monovision as well as simultaneous-imagery. Dynamic methods generally attempt to make use of at least some of the still-active elements of the accommodation system. They include procedures which are supposed to modify the relative geometry of the ciliary muscle and lens, or which reduce the stiffness of the presbyopic lens either by replacing it with other natural or man-made material or by subjecting it to femtosecond laser treatment. Alternatively the natural lens may be replaced by some form of intraocular lens which changes power as a result of forces derived from the still-active ciliary muscle, zonule and capsule, or other sources.


CONCLUSIONS
At present, multifocal intraocular lenses appear to offer the most consistent and reliable surgical approach to surgical presbyopic correction. They have obvious advantages in convenience and stability over optically-similar, simultaneous-image presbyopic contact lenses but this must be balanced against their relative inflexibility in cases of patient dissatisfaction. Dynamic methods remain largely experimental. Although some approaches show promise, as yet no method has demonstrated a reliable, long-term ability to correct distance refractive error and to appropriately change ocular power in response to changes in viewing distance over the normal range of interest.
Faculty of Life Sciences, University of Manchester, Manchester, UK.
W Neil
WN
Charman
D048988:Corneal Surgery, Laser / Q000379:methods; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000379:methods; D054018:Lasers, Excimer / Q000627:therapeutic use; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D009801:Oculomotor Muscles / Q000601:surgery; D011305:Presbyopia / Q000601:surgery*
accommodating intraocular lenses; corneal presbyopic surgery; lens photodisruption; lens refilling; multifocal intraocular lenses; scleral procedures