Wavefront-guided spectacles a help after LASIK

January 15, 2008

Wavefront-guided spectacles may provide a better solution than standard eyeglasses for patients with subjective complaints stemming from higher-order aberrations after LASIK.

Key Points

La Jolla, CA-Wavefront-guided spectacles may provide a better solution than standard eyeglasses for patients with subjective complaints stemming from higher-order aberrations (HOAs) after LASIK. Eighty percent of patients choose wavefront lenses over standard lenses in a comparison of the two, according to Mihir Parikh, MD, in private practice in La Jolla, CA.

The popularity of LASIK continues to increase; almost 61% of the procedures were wavefront-guided ablations in the fourth quarter of 2005, Dr. Parikh said.

"Interestingly, from 76% to almost 100% of patients select to undergo a wavefront-guided LASIK procedure if it is offered," Dr. Parikh said.

"More patients are seeing 20/20 following a wavefront procedure, and there is less night-vision aberration following surgery," he added.

Not every patient is 100% satisfied after LASIK, however. Dr. Parikh proposed an innovative approach to satisfying this population of patients.

"There are different types of 20/20. The patient may be seeing 20/20 but without the quality of vision that he or she was expecting," he said.

A few options exist for these patients, such as waiting for the vision to improve, considering an enhancement procedure that is possibly wavefront-guided, or glasses or contact lenses, Dr. Parikh said.

"If the choice is glasses, why not prescribe wavefront-optimized glasses to make the vision as sharp as possible?" he asked.

Dr. Parikh reported that wavefront aberrometry was performed on his patients using a proprietary aberrometer (Z-view, Ophthonix Inc.), and wavefront-guided spectacles (IZon, Ophthonix) were prescribed.

"The aberrometry has a nice correlation with the manifest refraction. Similar to the [wavefront elevation (CustomVue, Advanced Medical Optics [AMO])] maps, the aberrometer reports the sphere, cylinder, axis refractive error, and the total HOAs in diopters," he said. "Trefoil, coma, and spherical aberration are also measured."

After the patient selects a frame, an antireflective coating is put on the front surface of the lenses and the sphere and cylinder corrections are put on the back surface. The wavefront data from the wavefront aberrometer are encrypted into the middle layer of the lenses.

Dr. Parikh demonstrated a simulation of how the lenses would work. On one side, he showed a standard lens correction, and on the other side a wavefront-optimized correction.

"With the HOAs neutralized, the image is crisper and cleaner," he said.

Dr. Parikh used this approach to treat five patients who were not perfectly satisfied with their LASIK outcomes. All had undergone uncomplicated, non-wavefront-guided laser eye surgery using the proprietary laser platform. After surgery, the patients had an uncorrected visual acuity of 20/30 or better, but they had persistent symptoms that included glare, halos, starbursting, and poor color contrast for 6 months after the initial surgery.

"We asked each patient to purchase two types of distance glasses," he said. "One was standard single-vision lenses using the manifest refraction, and the other was single-vision . . . lenses with wavefront-guided correction."

The patients were blinded to which glasses contained the wavefront-guided correction and which was standard. Each patient was instructed to wear a pair of glasses consistently for 2 weeks and then switch to the other pair of glasses for 2 weeks. At the completion, the patients were asked to choose which glasses they preferred and to complete a quality-of-vision questionnaire modeled after what VISX (acquired by AMO in 2005) used to obtain FDA approval for its wavefront platform.

The five patients (three men, two women) had a mean preoperative spherical equivalent of –5.32 D (range, –1.25 to –8.63 D). The mean postoperative refractive error was about –0.79 D. The root mean square was 1.6 μm.