Monovision is a technique where one eye (usually the dominant eye) is corrected for clear distance vision, and the other eye is corrected for comfortable near vision. Monovision allows a person to see close objects clearly with one eye and distance objects clearly with the other eye. The vision part of the brain tends to filter out the image from the eye that is not in clear focus, so those who have monovision eventually do not pay attention to the eye that is not as clearly focused. Those who have monovision are often able to see well enough both at distance and near to do things at any age without corrective lenses.
Monovision can be achieved with contact lenses, cataract surgery, or laser vision correction (LASIK or PRK). If you are considering a vision correction procedure, your doctor can trial monovision with you through the use of contact lenses prior to undergoing a permanent laser vision correction procedure.
For those undergoing cataract surgery who are considering the intraocular lens for monovision, an in depth discussion with your surgeon is necessary to be sure that this is the correct decision for you.