CUSTOMIZED WAVEFRONT LASIK: THE ULTIMATE EVOLUTION OF LASIK In the year 2000, the internationally acclaimed medical journal, Journal of Cataract and Refractive Surgery, published an exploratory article by Dr. Shapiro on Customized Wavefront LASIK. Dr. Shapiro became one of the first surgeons in the world to author an article on this breakthrough technology. Three years later, the FDA approved Customized Wavefront LASIK for the treatment of nearsightedness and astigmatism. Since the time of FDA approval, Dr. Shapiro has been an international leader in guiding the clinical evolution of customized wavefront laser vision correction. Dr. Shapiro was the first surgeon in the world to publish about the use of customized wavefront LASIK to correct night vision problems from older, conventional LASIK surgery. This landmark paper openied up a new therapeutic role for wavefront surgery for patients with night vision problems who previously had no good treatment options. Dr. Shapiro was also the first surgeon in the world to describe the use of customized wavefront LASIK to improve optics after previoius conventional PRK surgery. Dr. Shapiro has also published the world's first article describing the use of third generation wavefront technology in managing complex small pupil LASIK cases which could not be successfully treated even with earlier forms of wavefront surgery. Dr. Shapiro's teaching articles on customized wavefront LASIK have been published worldwide. Dr. Shapiro recommends third generation Customized Wavefront LASIK for all appropriate candidates as representing the state of the art in laser vision correction. As with all advanced technologies, however, the surgeon's skill and degree of specialization remain the most critical elements to achieving optimal results. Conventional (non-wavefront) LASIK, through such advances as three dimensional eye tracking and excimer lasers capable of billionth of an inch accuracy, has evolved over the years to offer outstanding results. When performed by an experienced surgeon with the best equipment, it is very common for patients undergoing the latest generation of conventional LASIK to see as well after surgery as they did with their glasses or contact lenses. In fact, conventional LASIK attempts to do exactly what glasses and contact lenses do, namely to fully correct one's nearsightedness,farsightedness, and astigmatism.
RAISING THE BAR: CUSTOMIZED WAVEFRONT LASIK
In May, 2003, the FDA approved the use of the Customized Wavefront LASIK using the VISX CustomVue System, an entirely new generation of laser vision correction and the predecessor of the system used by Dr. Shapiro. With CustomVue custom wavefront LASIK, the goal of surgery is no longer to equal the best glasses or contacts, but to actually exceed the quality of vision of glasses or contacts. The results of the FDA trials were outstanding:
- 100% of patients could pass a driver's test without glasses or contacts.
- 98% of patients saw 20/20 or better
- 70% actually ended up with vision better than 20/20.
- Four times as many patients were happy with their night vision after Customized Wavefront LASIK than were happy before surgery with their glasses or contact lenses.
- No one in the FDA study reported worse night vision after Custom Wavefront LASIK than with their glasses or contacts before surgery.
These are the best data ever recorded by the FDA for any format of LASIK. This data, as good as it is, reflects the original, first generation format of customized wavefront LASIK. Today, we are in the third generation of customized wavefront LASIK, which has made results even better. Dr. Shapiro considers third generation wavefront to be the mature form of the technology. Obviously, LASIK is still eye surgery and results of surgery can never be guaranteed, but this FDA data shows how successful a surgery Customized Wavefront LASIK using the VISX CustomVue system is.
HOW CUSTOMIZED WAVEFRONT LASIK WORKS
Glasses, contact lenses, and conventional LASIK all work by correcting a patient's nearsightedness, farsightedness, or astigmatism using standardized, but not customized, lenses measured in units called diopters. The patient is asked to select the best “optically fitting” corrective lens (“which is better – one or two”) in the same way a shopper will try on different shoes until the best size is selected. Just as shoe sizes come in ½ size steps, glasses and contacts measurements come in ¼ diopter steps. The best “off the shelf” lenses selected by the patient become the patient’s glasses or contacts prescription (just as the best “off the shelf” shoes will describe the shopper’s shoe size). Conventional LASIK simply places this glasses or contacts prescription into the cornea. Because laser technology has become so advanced, conventional LASIK has become extremely successful at essentially replicating the glasses or contacts prescription in the cornea.
Glasses, contacts, and conventional LASIK correct vision by selecting standardized, but not customized, lenses which best correct the vision, analogous to selecting off the shelf shoes at a shoe store. These standardized lenses come in ¼ diopter increments.
Recent advances in astrophysics using a technique called wavefront analysis have allowed us to measure optical systems ranging from high power telescopes to the human eye with vastly more precession. Through wavefront analysis, we now know that our concept of merely using standardized lenses addressing nearsightedness, farsightedness, and astigmatism to correct the eye was too simplistic.
Rather, each eye has its own unique complex optical distortions, or optical "fingerprint." This fingerprint of optical distortion is called the Waveprint and no two people have the same optical fingerprint. Simply correcting nearsightedness, farsightedness, and astigmatism by using standardized lenses measured in ¼ diopters does not perfectly correct this optical fingerprint -- these “off the shelf” lenses only offer an approximate correction just like an off-the-shelf shoe may not give an exact fit. By contrast, customized wavefront LASIK (to use the shoe analogy further) is like placing your foot in a mold which will conform to its every nuance and curvature in order to make a customized pair of shoes which fit perfectly.
The three dimensional wavefront image, or "optical fingerprint" of the visual distortions and aberrations in a nearsighted patient's eye. This complex computerized image is mapped for each patient and downloaded into the laser, which can replicate it in the cornea with billionth of an inch accuracy. This provides a level of precision of treatment beyond that offered by glasses or contact lenses.
Wavefront technology allows us to measure and map the eye’s complicated optical fingerprint with instruments capable of 25 times the accuracy of conventional glasses or contacts measurements. Whereas glasses and contacts measurements use lenses measured in 0.25 diopter increments, sophisticated wavefront sensors are capable of working in 0.01 diopter increments. In fact, over 200 sensors, each capable of 0.01 diopter accuracy, are placed in front of the pupil to measure the return trip of an infra-red laser beam which is reflected off the retina in the back of the eye. This reflected beam will pass through all the optical aberrations and distortions of the eye on its return trip. In this way, an extraordinarily accurate three dimensional mapping of the entire eye’s optical system is created.
The VISX Wavescan is used by Dr. Shapiro to create the three dimensional map of the wavefront image, or "optical fingerprint" of your eye. An invisible infra-red laser is shined into the eye and over 200 sophisticated sensors map out the returning reflection of this laser from the back surface of the eye. To insure accuracy, four distinct wavefront maps are created within milliseconds and they are cross-checked to be sure they correlate with each other.
Thus, not only are wavefront sensors 25 times more accurate, they are mapping the three dimensional optical fingerprint of the entire eye rather than just two parameters (nearsightedness and astigmatism) of that complex optical geometry.
This three dimensional map is then downloaded into the laser's computer, and, taking full advantage of the billionth of an inch accuracy of the eye-tracked VISX S4 IR excimer laser, the optical fingerprint is sculpted directly into the cornea to create a truly custom tailored correction. Since glasses and contact lenses, and conventional LASIK, only correct nearsightedness and astigmatism using standardized lenses measured in ¼ diopter steps, this is now the first time in medical history that we can actually strive to correct the eye's entire optical system.
Thus, wavefront LASIK corrects vision with a precision and customization beyond that offered by glasses or contacts. Aberrations and distortions beyond nearsightedness and astigmatism can now be corrected. This opens up the rather astonishing potential of vision superior to anything the patient has ever seen before. Customized wavefront LASIK is truly a breakthrough in vision correction and one that we are proud to be so deeply involved with at the Shapiro Laser Eye Center.
Results
As with any surgery, results can never be guaranteed and there are risks to LASIK. However, as LASIK has continued to evolve into the most advanced form of Customized Wavefront LASIK incorporating Fourier wavefront reconstruction, iris registration systems, and three dimensional eye tracking, the results have correspondingly improved to previously unimaginable levels. Dr. Shapiro presented a landmark study of his techniques for Customized Wavefront LASIK at the annual international meeting of the Association for Research and Vision in Ophthalmology (ARVO) in Ft. Lauderdale, Florida in May, 2010 . In this study 96% of his Customized Wavefront LASIK patients ended up with vision better than they had ever seen with glasses or contact lenses. The other 4% ended up with vision equal to their glasses or contacts. No patients in his study had vision worse than their glasses or contacts. |
