Take-home message: The various excimer ablation technologies have their pros and cons. Wavefront-guided ablations using aberrometry can provide the vast majority of patients with uncorrected vision of 20/20 with fewer postoperative visual symptoms.
San Diego - Over the years, LASIK has moved forward by leaps and bounds–with each new added technology further maximizing vision via innovative means. The vast majority of patients can now achieve uncorrected visual acuities of 20/20 or better and, compared with the early days, there is now far better quality of vision.
But surgeons did not reach this level of excellence overnight. Some of the important steps between the introduction of LASIK performed using a conventional procedure and wavefront-guided ablations were the improvements in the laser algorithms, development of sophisticated eye trackers and cyclotorsional alignment, and use of the femtosecond laser to create flaps.
However, the greatest improvements in the quest for perfect vision have been refinements in the ablation profile and the data used to create it, according to Steven Schallhorn, MD.
The first foray into refractive correction was the conventional or standard ablation, which was based on the spectacle prescription and utilized the Munnerlyn formula for the ablation profile.
The Munnerlyn formula correctly and precisely calculates the treatment profile to treat the refractive error, but it does not account for the healing response and the variability in the amount of tissue removed by each laser pulse. The conventional correction is a simple and straightforward procedure that removes a minimal amount of tissue. The surgery effectively reduces patients’ need for spectacle or contact lens correction.
However, spherical aberration and other higher-order aberrations (HOAs) can be induced which are associated with night vision difficulties. In addition, complex treatments cannot be performed.
Optimized LASIK treatment