As you will recall from the introductive to refractive surgery, there are three common refractive errors: myopia, hyperopia and presbyopia.  Presbyopia commonly develops after a patients turns 40 and reduces a person’s ability to change his focus (accommodation) between near and far images.  Simply put, the natural lens loses its ability to flex when changing focus, and eventually the focus remains on distant objects.  When accommodation is lost, most patients turn to reading glasses or bifocals to read small print and other items within an arm’s length. 

Restoring accommodation has been an elusive task, and only the Crystalens intraocular lens (permanent) and conductive keratoplasty (temporary) procedures have been approved by the FDA for this purpose.  The Crystalens implant is attached to the same eye muscles that allowed the natural lens to flex for accommodation.  From our practical experience with patients, we find that Crystalens patients have excellent far and intermediate vision, and good near vision.  Most Crystalens patients will still need reading glasses for prolonged reading of fine print such as a newspaper. 

The ReSTOR intraocular lens is referred to as a pseudo-accommodating lens.   The ReSTOR lens is not attached to the muscles that allow the lens to flex for accommodation, but the ReSTOR lens has a multi-focal design that still allows the patient to see near and far.  The ReSTOR lens will not be widely available until the second half of 2005, and it is unclear how successful the lens design will be.

The long-standing solution to presbyopia has been monovision, where one eye is corrected for optimal distance vision and the second eye is corrected for optimal near and intermediate vision.  Monovision can be achieved through contact lenses, LASIK, PRK and lens implants, but not every patient enjoys monovision.  Consequently, if a patient is seriously considering a surgical procedure that will aim for monovision, we first have patients try this correction with disposable contact lenses.  Many of our patients rave about monovision, but it is not for everyone.