Custom hyperopic LASIK has some advantages over conventional LASIK

Although differences were not as dramatic as those seen with myopic LASIK, one surgeon said, hyperopic patients can benefit from custom LASIK.

Issue: September 15, 2006

ByKatrina Altersitz

Hyperopic patients can benefit from customized wavefront-guided LASIK, although the advantages are more subtle than those seen with myopic LASIK, one investigator said.

James J. Salz

James J. Salz, MD, reported the findings of a multicenter study of hyperopic LASIK using the CustomCornea system with the Alcon LADARVision laser at the American Society of Cataract and Refractive Surgery meeting earlier this year.

The study included eyes with +0.75 D to +4.25 D of spherical error and 0 D to –3 D of cylinder, up to +4 D spherical equivalent, treated with either CustomCornea or conventional hyperopic LASIK using the Alcon laser.

“When we started this study, my intuition was that it wouldn’t make that much difference in hyperopic eyes to do wavefront treatments since you’re not really radically changing the shape of the cornea like you do in myopic eyes,” Dr. Salz said. “The advantages don’t knock your socks off quite as much as they do in myopic eyes, but I think there is evidence that this is also going to benefit patients.”

Since the time of Dr. Salz’s presentation, Alcon has received an expanded indication for treatment of hyperopia with its LADARVision 4000 and LADAR 6000 lasers. The company announced in May that its lasers are now approved to treat hyperopia from 0.75 D to 5 D with up to –3 D of astigmatism.

Dr. Salz said the study demonstrated advantages with the wavefront-guided treatment, including better high and low contrast visual acuity, greater reduction in total wavefront error, less increase in higher order aberrations and more reduction in both total root mean square (RMS) error and higher-order error.

Purpose

In order to show the benefits of performing custom wavefront-guided LASIK in hyperopic patients, Dr. Salz and colleagues compare the results of wavefront-guided hyperopic LASIK to conventional hyperopic LASIK.

“The purpose was to compared the clinical outcomes of LASIK on wavefront-guided vs. conventional,” he said, “so rather than just present the wavefront-guided results we took a similar group of patients treated with the same system and compared them.”

Postoperatively, the researchers measured high-contrast visual acuity, low-contrast visual acuity, refraction, contrast sensitivity and wavefront patterns.

There were 95 eyes in the conventional group and 239 eyes in the custom-treated group. Dr. Salz said that the sphere, the cylinder and the range of error were similar preoperatively in the two groups, making them comparable.

The data he presented were based on postoperative follow-up at 6 months.

Visual acuity

Postoperatively, visual acuity in the custom-treated group was better than or equal to visual acuity in the conventional LASIK group in all categories measured, Dr. Salz said.

High contrast visual acuity at 6 months showed a slightly higher number of eyes in the custom group achieving 20/20 visual acuity. Sixty-three percent of eyes in the custom group vs. 55% in the conventional group achieved 20/20 or better. In the custom group, 83% of eyes achieved 20/25 or better visual acuity compared to 76% in the conventional. In both groups, 96% of eyes achieved 20/40 or better, he said.

In high-contrast best corrected visual acuity, the results were similar in the two groups, Dr. Salz said. In the custom group, 28% of patients gained one line of BCVA vs. 23% in the conventional group. The percentages of patients who had no change or lost lines were similar, he said.

Accuracy of postoperative refraction was also similar between the groups, Dr. Salz said. In the custom group 73% had a postop refraction within ±0.5 D of target vs. 69% in the conventional group. In both groups, about 90% of eyes were within 1 D of target refraction.

The CustomCornea eyes had slightly better low contrast uncorrected visual acuity than the conventional eyes, Dr. Salz said, with 23% vs. 13%, respectively, achieving 20/25 or better, and 78% vs. 57% 20/40 or better. These were statistically significant differences.

Aberrations

Dr. Salz and colleagues also observed better results in the CustomCornea eyes in postoperative measurement of wavefront aberrations.

“In terms of induction of higher-order aberrations, there was an improvement again in the custom group,” Dr. Salz said. In the custom group, 8% of eyes had induced higher-order aberrations, while in the conventional group 29% had induced aberrations, he said.

More eyes in the custom-treated group had a reduction of wavefront aberrations postoperatively. Higher order aberrations were reduced in the custom group in 56% of eyes vs. 33% in the conventional group, he said.

For more information:

James J. Salz, MD, can be reached at 444 S. San Vicente Blvd., Suite 704, Los Angeles, CA 90048; 323-653-3800; fax: 323-653-3898; e-mail: jjsalzeye@aol.com. Dr. Salz is a paid consultant for Alcon and the medical monitor of the company’s excimer laser studies.

Alcon, maker of the CustomCornea system for the LADARVision 4000 and LADAR 6000 excimer lasers, can be reached at 6201 South Freeway, Fort Worth, TX 76134; 817-293-0450; Web site: www.alconlabs.com.

Katrina Altersitz is an OSN Staff Writer who covers all aspects of ophthalmology.