Editing Contact lens (section)

====Correction of presbyopia====
Correction of [[presbyopia]] (a need for a reading prescription different from the prescription needed for distance) presents an additional challenge in the fitting of contact lenses. Two main strategies exist: multifocal lenses and monovision.

Multifocal contact lenses (e.g. bifocals or progressives) are comparable to spectacles with [[bifocals]] or [[progressive lens]]es because they have multiple [[focus (optics)|focal points]]. Multifocal contact lenses are typically designed for constant viewing through the center of the lens, but some designs do incorporate a shift in lens position to view through the reading power (similar to bifocal glasses).

Monovision<ref>{{Cite journal |last=Lebow |first=KA |last2=Goldberg |first2=JB |year=1975 |title=Characteristic of binocular vision found for presbyopic patients wearing single vision contact lenses |journal=Journal of the American Optometric Association |volume=46 |issue=11 |pages=1116–23 |pmid=802938}}</ref> is the use of single-vision lenses (one focal point per lens) to focus an eye (typically the dominant one) for distance vision and the other for near work. The brain then learns to use this setup to see clearly at all distances. A technique called modified monovision uses multifocal lenses and also specializes one eye for distance and the other for near, thus gaining the benefits of both systems. Care is advised for persons with a previous history of [[strabismus]] and those with significant phorias, who are at risk of eye misalignment under monovision.<ref>{{Cite journal |last=Pollard |first=Zane F. |last2=Greenberg |first2=Marc F. |last3=Bordenca |first3=Mark |last4=Elliott |first4=Joshua |last5=Hsu |first5=Victoria |date=September 2011 |title=Strabismus Precipitated by Monovision |journal=American Journal of Ophthalmology |volume=152 |issue=3 |pages=479–482.e1 |doi=10.1016/j.ajo.2011.02.008 |pmid=21669405}}</ref>   Studies have shown no adverse effect to driving performance in adapted monovision contact lens wearers.<ref>{{Cite journal |last=Wood |first=Joanne M. |last2=Wick |first2=Kristan |last3=Shuley |first3=Vicki |last4=Pearce |first4=Brendon |last5=Evans |first5=Dean |date=6 May 1998 |title=The effect of monovision contact lens wear on driving performance |journal=Clinical and Experimental Optometry |volume=81 |issue=3 |pages=100–103 |doi=10.1111/j.1444-0938.1998.tb06727.x |pmid=12482258 |s2cid=38392636}}</ref>

Alternatively, a person may simply wear reading glasses over their distance contact lenses.