Night Vision and LASIK
Submitted by Dr. Dean Dornic on Sun 03/13/2011 - 11:37
Many people who have never had eye surgery, if they are careful observers, can notice some starburst, halo, glare, or shadows in their vision under low light conditions, especially if they need to wear glasses or contact lenses. It is common to notice one or more of these after LASIK eye surgery, especially during the early postoperative period. These side effects generally diminish with time but some patients will notice one or more of these even with excellent correction, sometimes for a long time or even indefinitely. Of those patients who do notice these side effects, most will find them annoying and it is possible that some patients may feel they cause mild to serious visual impediments.
The LASIK procedure creates a change in curvature in the central part of the cornea. If changing the corneal curvature also results in distortion of the cornea then aberrations in vision quality may result. These aberrations in vision may be most noticeable at night, when the pupil opens wide. This can result in seeing a halo type effect or perhaps just a decreased contrast or sharpness of vision. Regardless of how it is described, there are some patients who feel that their night or reduced light vision is poor even when their uncorrected vision is good or excellent in normal lighting. This may be a significant issue for some patient for night driving, playing tennis or baseball at night or other similar activities, even before refractive surgery is performed. A technology developed by AMO/VISX termed CustomVue and utilized in the iLASIK procedure was developed in an effort to improve night vision. The CustomVue technique makes use of a wavefront analyzer to measure and correct visual aberrations. Clinical studies show that more patients are actually satisfied with their night vision after LASIK when this technique is used. The wavefont guided CustomVue technique should not be confused with the wavefront optimized technique utilized by the Wavelight/Allegretto laser. Only the CustomVue technology associated with iLASIK results in better night vision.