PresbyLASIK Surgery
Usually beginning at about age 40, a reduction in eye's
natural ability to focus flexibly results in many people needing
to wear bifocals or multi-focal contact lenses in order to
manage seeing clearly at distances both near and far. This
condition, in which the eyes exhibit a progressively diminished
capacity to focus on near objects with age, is called presbyopia.
Recent advances in corneal ablation technique using Excimer
lasers allow ophthalmologists to correct for presbyopia, giving
patients the ability to see near objects clearly without glasses
or contact lenses. In general, presbyopic surgery, also known as
PresbyLASIK, and Multi-focal LASIK, applies the principles of
LASIK surgery to create a multi-focal corneal surface, with a
central area which is hyperpositive for near vision, leaving the
mid-peripheral cornea for far vision.
Standard LASIK reshapes the eye's surface to focus better at
either near or far ranges, depending on whether a patient has
hyperopia (is farsighted) or myopia (is nearsighted). But with
the loss of flexibility as eyes age, some can no longer can see
clearly at all distances simultaneously, even with conventional
glasses or contact lenses, or if they already have had LASIK for
a problem like nearsightedness.
Until recently presbyopic eyes were addressed with a LASIK
procedure that provides monovision. In such cases, one eye is
corrected for better distance vision, while the other eye is
corrected to enhance near vision. However the treatment has been
seen as less-than-successful, as many people have difficulty
adapting to monovision, which can cause problems such as a loss
of depth perception.
PresbyLASIK, or Multi-focal LASIK, which allows patients to
retain binocular vision, is currently under clinical trials in
the US and has not yet been approved for general treatment by
the FDA. However, many ophthalmologists are hopeful that trial
data and the success of the technique in other countries will
help make the procedure available soon to US presbyopia
patients.
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