Monovision

Monovision is the most widely practised arrangement to produce good distance and near vision at the same time so as to reduce dependence upon reading glasses. It means setting the focus of the dominant eye for distance vision and making the other eye slightly short sighted to focus for near vision. The brain automatically switches between eyes to concentrate on the clearer image and suppresses the less clear image, depending upon what is being viewed.

Many people who wear contact lenses are already accustomed to monovision and have one eye corrected for distance and the other for near. Some people with good distance vision in both eyes avoid the need for reading glasses by wearing a contact lens for near vision in just one eye, a bit like wearing a monocle.

Surgery to replace the natural lens of the eye can create the same effect on a more permanent basis by implanting a distance lens in one eye and a near or intermediate focus lens in the other.