Wavefront-optimized LASIK and PRK use a semi-customized excimer laser treatment designed to control a specific type of higher-order aberration called spherical aberration (SA).

It is believed that high levels of SA contribute to halos, glare and other night vision problems, even in the absence of refractive errors such as nearsightedness and astigmatism.

Wavefront-optimized LASIK and PRK: Study design and methods

Olivia Lee, MD and colleagues at Emory University (Atlanta, Ga.) recently conducted a review of 346 consecutive eyes of 176 patients that underwent wavefront-optimized excimer laser vision correction.

Seventy percent of the eyes were treated with wavefront-optimized LASIK and 30 percent underwent wavefront-optimized PRK. All procedures were performed by the same surgeon using the same proprietary excimer laser technology (Allegretto Wave, Alcon Laboratories).

Questionnaires were given to patients before and after surgery to assess the incidence of halos and other vision disturbances they encountered when driving at night.

Study results and conclusions

Evaluating the subjects’ night vision problems, the researchers found:

• Approximately 75 percent of subjects experienced no change in night vision disturbances after surgery.
• No subjects had a severe worsening of symptoms of night vision disturbances.
• 1.2 percent of subjects experienced moderate worsening of symptoms.
• 14 percent of subjects noted some improvement in the quality of their night vision after surgery.

“Night vision complaints rarely occur after wavefront-optimized laser ablation,” Dr. Lee said. “In our study, patients were more likely to experience no change or have a diminution of symptoms than to have a worsening.”

The researchers also noted that pupil size does not appear to be correlated with halos or night vision problems after surgery.

SOURCE:  Study: Wavefront-optimized excimer laser ablation not culprit in night vision disturbances. Ophthalmology Times. Meeting E-News. Published online April 4, 2009.

Recently, Perry S. Binder, MD, a prominent refractive surgeon in San Diego, California, retrospectively reviewed the outcomes of LASIK procedures he performed using several different excimer lasers and ablation algorithms (computerized treatment programs). His goal was to see which of these combinations produced the best LASIK outcomes for his patients.

LASIK comparison: Study design and methods

Dr. Binder compared the results of 721 eyes of 458 myopic patients who underwent LASIK surgery in his practice. He performed all the LASIK surgeries in the study group himself.

Five different treatment groups were analyzed:

• Conventional LASIK with a Visx Star excimer laser (Abbott Medical Optics, Santa Ana, Calif.)
• CustomVue wavefront-guided LASIK with a Visx Star excimer laser
• Conventional LASIK with a LADARVision excimer laser (Alcon, Inc., Fort Worth, Texas)
• Wavefront-guided LASIK with a LADARVision excimer laser
• Wavefront-optimized LASIK with an Allegretto Wave excimer laser (Alcon, Inc.)

In all cases, the corneal flap was created with an IntraLase femtosecond laser, and aberrometry measurements were taken before and after surgery to determine the level of pre-op and post-op higher-order aberrations.

Follow-up exams were performed for a minimum of one month after all surgeries and the mean follow-up for the five treatment groups ranged from one to 26 months.

Results were evaluated separately for patients who had no pre-operative astigmatism (“spheres” group) and those who did (“spherocylinders” group).

Results and conclusions

Analysis of the data in the study revealed:

• All laser platforms used for LASIK performed well and improved uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA).
• CustomVue wavefront-guided LASIK produced the best UCVA results among spheres, with 42 percent seeing 20/16 or better after surgery.
• Wavefront-optimized LASIK with the Allegretto Wave laser produced the best UCVA results among spherocylinders, with 30 percent attaining 20/16 or better uncorrected visual acuity after surgery.
• Overall, CustomVue wavefront-guided ablations with the VISX laser provided better visual outcomes than conventional LASIK ablations with the same laser.
• Wavefront-guided ablations with the LADARVision laser provided similar outcomes as conventional LASIK treatments with the same laser.
• All of the lasers induced higher-order aberrations (HOAs).
• Patients with greater pre-operative HOAs did better with a wavefront-guided or wavefront-optimized LASIK treatment than with a conventional LASIK treatment.
• The CustomVue wavefront-guided LASIK treatment was best overall in keeping HOAs to a minimum.

Based on the results of this study, Dr. Binder says he significantly increased the percentage of CustomVue wavefront-guided LASIK procedures he performs, as this procedure appears to provide the best overall outcomes.

SOURCE:  Comparing conventional, custom and wavefront-optimized LASIK. EyeWorld. May 2009. (Supplement: Premium Clinical Options for Cataract and Refractive Surgery, sponsored by Abbott Medical Optics.)