Presbyopia is caused by an age-related process. This differs from astigmatism, nearsightedness and farsightedness, which are related to the shape of the eyeball and are caused by genetic and environmental factors. Presbyopia generally is believed to stem from a gradual thickening and loss of flexibility of the natural lens inside your eye and results in the inability to focus on objects up close.
Eyeglasses with bifocal or progressive addition lenses (PALs) are the most common correction for presbyopia. Bifocal means two points of focus: the main part of the spectacle lens contains a prescription for distance vision, while the lower portion of the lens holds the stronger near prescription for close work. […then you can read the fine print and see the big picture too.. ]
Presbyopes also can opt for multifocal contact lenses, available in gas permeable or soft lens materials. However, older adults who wear multifocal contact lenses to correct problems with near vision may have greater difficulty driving at night than their counterparts who wear glasses.
According to Byoung Sun Chu, Joanne M. Wood and Michael J. Collins, older adults between ages 45-64 years wearing multifocal contact lenses resulted in significantly slower driving speeds at night than wearing progressive addition glasses. While slower driving would seem to reduce the likelihood of hitting nighttime road hazards, the authors reported a reduced ability to recognize road hazards among multifocal contact lens wearers.
The study also showed that multifocal contact lens wearers were able to see road signs, but at a much shorter distance than those wearing glasses, potentially decreasing the reaction time required for a driver to make necessary navigational decisions.
"For those patients who drive long distances and hours at night, practitioners should carefully consider the best form of correction of presbyopia for these patients," said Byoung Sun Chu, "One alternative is to prescribe the multifocal contact lenses for daytime use and a different correction for driving at night."