piggyback lens


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piggyback lens

A combination of a hard contact lens placed over a soft contact lens, used to treat two different ocular conditions.
See also: lens
References in periodicals archive ?
Piggyback lens systems first emerged in the late 1960s.
Once the lens implant is placed in the eye, the focusing distance at which you see clearly can only be changed by changing the lens with a new one, placing a second or piggyback lens in your eye, or having a surgery such as LASIK in which the surface of your eye is reshaped to change the focus.
The disadvantages of piggyback lens systems are: (a) Not all eyes, particularly very steep corneas such as advanced keratoconus and steep grafts, will be able to wear a soft lens without fluting at the edge.