I have been performing LASIK since its inception back in 1996. Hard to believe its been 14 years. What I am now seeing on an ever increasing basis is patients who have had LASIK in the past complaining of a deterioration in their vision. Many of these patients come in assuming that their LASIK is "wearing off" and that they are in need of a "fine tuning." What is actually going on is that they have developed visually significant cataracts.
A cataract is an aging change that causes a clouding of the eye's cryastaline lens. Once visually significant, the treatment of choice is cataract extraction with the implantation of an intraocular lens (IOL). Cataract surgery in patients who have previously had LASIK poses several unique issues.
The calculations to determine the correct IOL power are not as accurate in eyes that have undergone LASIK. To improve the accuracy of these calculations it is helpful to have records from before the LASIK surgery including:
- Pre operative refraction
- Pre operative corneal curveature
- Stable post operative refraction before the start of cataracts
Many new techniques are being investigated to improve on IOL calculations. Just last month an article appeared in Journal of Refractive Surgery titled: Calculation of Intraocular Lens Power Using Orbscan II Quantitative Area Topography After Corneal Refractive Surgery. It concluded that "In eyes with previous corneal refractive surgery, IOL power calculation can
be performed with reasonable accuracy using the Orbscan II central 2-mm
Even with all these new techniques, post LASIK patients are prone to encounter a "refractive surprise" following cataract surgery. A refractive surprise occurs when a patient's final Rx following cataract surgery is off the mark. Refractive surprise can be treated in several ways, depending on the amount of the surprise:
- Mild surprises can be treated with glasses, contact lenses, or possibly with a LASIK touch up.
- Large surprises can be treated with either an IOL exchange or the implantation of a piggy back IOL.
No matter how carefully caculations are made before cataract surgery, refractive surprises will happen. In my opinion, patients who develop cataracts following LASIK, should seek the care of a surgeon with vast experience in both refractive and cataract surgery. The trick here is to both minimize the amount of the surprise and to be able to efficiently treat the surprise when it is encountered.
One benefit many of my LASIK-cataract patients have is the ability to implant a multifocal IOL such as the ReSTOR. Following the implantation of this lens, these patients are now able to see both near and far again without glasses!