I don’t like to use the word “custom” when referring to Lasik. The term “Custom Lasik” is misleading, because it implies that there is also some type of Lasik that is non–custom. Actually, every Lasik treatment for every eye is specifically ‘customized’ to treat the vision in that eye, just as every pair of glasses or contact lenses is specifically ‘customized’ for the person who will be using them.
The term “Custom Lasik”, which is essentially a marketing gimmick, refers to an optical measurement known as the wave front. Notice how many vision correcting systems and lasers have the word ‘wave’ in their name. The wave front is a concept described by the Belgian physicist Zernike in 1934.
When a patient is measured for eye glasses or contact lenses, we put a series of lenses in front of each eye and ask, “which is better, this lens or that lens”. This kind of testing is used to measure lower order aberrations, and it is excellent for glasses and contact lenses. Wave front technology can be used to measure higher order aberrations, which can be important part of Lasik treatments. All modern Lasik treatments correct lower order aberrations, and combine that with one of two different types of wave front treatments: Wave Front Guided (WFG) and Wave Front Optimized (WFO). Most Lasik lasers in the United States can perform WFG treatments, but not WFO treatments. The WaveLight Allegretto laser that we use at Barnet Dulaney Perkins Eye Center can do both WFG treatments and WFO treatments, although we definitely prefer to use WFO treatments for our patients.
My comments are not intended as a negative criticism of WFG Lasik treatments. In eye surgery medical journals, some articles conclude that WFO treatments are better than WFG treatments. Some articles state the opposite. Other articles conclude that WFO and WFG produce equally good results.
Lasik treatments for patients who are nearsighted change the normal shape of the cornea (front ‘window’) of the eye in a way that actually induces a type of higher order aberration called spherical aberration. Spherical aberration is the leading cause of night time glare and halos around lights after ‘successful’ Lasik. WFO treatments are specifically customized for every eye to maintain the normal shape of the cornea. WFG treatments do not address this problem. That is why the WaveLight Allegretto laser is the only Lasik laser in the United States approved by the FDA to reduce the risk of night time glare.
WFG treatments are intended to measure higher order aberrations that are present in the eye before Lasik and to correct them as part of the Lasik treatment in an attempt to get ‘super vision’. A potential problem with WFG treatments is that higher order aberrations can change with time so that a WFG treatment that is correct for the eye now may not be correct in the future.
Ronald W. Barnet, MD
March 2010