NEW LASIK TECHNOLOGY

Over the past ten years there have been major improvements in the science and technology of Laser Vision Correction. This knowledge has helped to address common clinical problems such as night vision difficulties, glare and halos. New technology includes improved eye tracking systems during the laser procedure, large treatment zones, iris registration, adjustments for pupil centroid shift and laser microkeratomes, which reduce flap complications. However, no development has caused more excitement and benefit for patients than Advanced CustomVue LASIK utilizing wavefront guided treatment. Wavefront customized treatment will be the predominant form of LASIK treatment for the foreseeable future.

Wavefront guided custom LASIK differs from conventional LASIK treatment in the way the eye’s optical error is measured. Accurate measurement of the optics of each eye is essential for a good visual outcome from LASIK. It is this series of numbers/calculations that is used to program the laser for reshaping the cornea.

Prior to wavefront guided LASIK, the surgeon objectively measured the eye with a handheld instrument or an automated measuring device, then asked the patient to subjectively refine the measurement. It should be noted that this measurement was an averaged measurement of the eye’s entire optical system and that the averaged measurement was used to treat the entire central 6mm of the corneal surface during the laser reshaping procedure. The reality is that the eye’s optical system is not uniform throughout the central 6mm measurement but until wavefront measurements became available there was no way to precisely measure the optics of light emanating from minute areas of the central cornea.

While conventional LASIK was and still is very effective treatment for nearsightedness, farsightedness and astigmatism, the new wavefront guided LASIK procedure has given surgeons the ability to provide patients with improved visual results compared to conventional LASIK.

Instead of using an averaged measurement of the eyes optical system as is done with conventional LASIK, custom wavefront guided LASIK uses a waveprint of the eye’s optical system as the guide for laser reshaping. The waveprint is more precise than an averaged measurement because data about the eye’s optical system is collected from hundreds of separate points over the central 6mm of the cornea. Rather than using an averaged measurement from the central 6mm of the cornea to reshape the entire cornea, the cornea reshaping is customized at each of the hundreds of points from which measurements are taken. When eyes examined in this way are compared, like fingerprints, no two optical systems (eyes) are the same. Therefore, no two corrections are similar but are personalized for each patient and eye.

A good analogy often used comparing custom to conventional LASIK is that of buying a custom suit. Many men or women can wear a standard size 38 or 6 suit “off the rack” but the fit will never be as good as a custom suit. Put simply, many more measurements are taken to improve the fit of a custom suit compared to the “off the rack” suit.

Iris registration is essentially iris recognition. This advance allows the laser's computer to recognize you as an individual so that the optical information from your customized wavescan is matched to the appearance of your iris. This ensures that the optical correction is placed on your cornea in the exact location from which it emanated. The wavescan instrument simultaneously records the optical correction and the pattern of your iris, preventing the optical correction from being placed on the wrong individual. Recognition of pupil centroid shift ensures that the treatment is optically centered. The center of the pupil can shift when the pupil dilates because the pupil often dilates asymetrically.  Pupil centroid shift compensates for the shift in the pupil center from undilated to dilated, recentering the optical treatment.

The bottom line for patients is that custom LASIK provides improved visual outcomes and reduces night vision problems associated with earlier conventional LASIK procedures.

IMPROVED VISUAL RESULTS – In the FDA study of CustomVue LASIK, 98% of study participants achieved uncorrected visual acuity of 20/20 and 70% achieved 20/16 or better. This is compared to 23% from Dr. Benedetto’s personal statistics with conventional treatment.

NIGHT VISION – 85% of study participants were satisfied or very satisfied with vision at night, compared with 65% who reported satisfaction with glasses or contacts before the procedure. Similar statistics were reported for glare at night.