Epi-LASIK comes out ahead of LASIK in clinical trials

 

UCVA is high but results are slower to peak, investigators say.

Lubrication of EpiEdge separator
with proparacaine prior to separation.

Mechanical separation of epithelial
sheet.
Source: Norwood Eyecare (Atlanta)

If refractive surgery patients want a safer procedure than LASIK, they may have to trade a little time for increased safety.
Interim clinical trial results have been released for the Centurion SES Epikeratome (Norwood Abbey Ltd., Melbourne, Australia), which employs a dull plastic edge that sweeps across the cornea to separate a hinged sheet of epithelium rather than cutting deeper into the corneal stroma like traditional microkeratomes.
The procedure with the Epikeratome, called Epi-LASIK, is touted by advocates as safer than LASIK because it avoids flap-related complications like buttonholes. And although Epi-LASIK has not yet been pitted head-to-head against LASIK in company-sponsored clinical trials, investigators agree that the procedure has a substantially slower recovery time than does LASIK.
That said, investigators were impressed with how UCVA improves over the course of a month. They believed that the final UCVA results were better than those they have seen after LASIK.
Here are some of the results, and reactions from investigators.

Visual acuity results

Although study results are still being analyzed, Norwood Abbey released interim data on numerous eyes that were entered into their Epikeratome multicenter clinical trial. Although the Centurion SES Epikeratome already has been approved by the Food and Drug Administration (FDA), the company has sought to further prove safety and effectiveness of the device to a U.S. audience.
Study participants did not have previous ocular surgery. Their pre-op spherical equivalent refractive correction ranged from –0.5 D to –8.00 D with no more than –2.5 D of astigmatism. Wavefront-guided and non-wavefront-guided procedures were performed.
In 130 eyes, the average pre-op UCVA was 20/200. After surgery, the UCVA improved to 20/50 on average by post-op day one. Improvement continued to 20/40 by day four, 20/32 by day seven, and 20/20 by the first post-op month.
“LASIK gives faster vision, there’s no question about it,” said Robert L. Kantor, M.D., director, Kantor Eye Institute, Sarasota, Fla. Dr. Kantor said the majority of his LASIK patients on post-op day one are 20/30 or better. Sometimes, he said, he even has 20/15 on day one with custom LASIK surgery.
“During the first week, I tell Epi-LASIK patients, ‘You are going to see well enough to function, but you’re not going to see perfectly; great vision comes a little later, between one and fours weeks post-op.’”
While Marguerite B. McDonald, M.D., F.A.C.S., clinical professor of ophthalmology, Tulane University, New Orleans, and medical monitor for the Centurion SES Epikeratome, agreed that though the Epi-LASIK doesn’t have a first day post-op “wow factor” like LASIK, the patients “are okay with it because they are so happy to have blade-free surgery, they are functioning fairly normally even during the first few days, and they know the final outcomes of surface ablation are better.”
Mark Volpicelli, M.D., Mountain View, Calif., and one of the physicians contributing cases to the clinical trials, agreed that final visual acuity results with Epi-LASIK appear to be better than with LASIK.
“At three months post-op, the uncorrected visual acuity of the 25 eyes we have performed so far have great vision. One eye is 20/25 and the remaining 24 eyes are at 20/20 or better,” Dr. Volpicelli said.
As far as higher-order aberrations, some decreased while others increased.
At three months post-op mean astigmatism decreased from 0.64 D pre-op to 0.31 D post-op. Mean trefoil also decreased from 0.17 D to 0.13 D. Coma increased slightly from 0.18 D to 0.26 D, and spherical aberration increased from 0.09 D to 0.18 D. Dr. McDonald said these increases, however, may not be statistically significant. Data analysis was still being performed, company officials said.
Investigators also tracked haze after the Epi-LASIK procedure, ranking it from 0 (no haze) to 4 (severe haze). Mean haze at post-op day ranked a 0.7. It decreased from there to 0.6 (day four), then to 0.3 (day seven), and 0.1 (month three). Dr. McDonald said none of the haze was visually significant.
“We have only one patient with trace haze at the one-month mark,” Dr. Volpicelli said. “None of our patients at the three-month mark had any haze.”
Despite this patient’s slight amount of haze, he was still 20/20 in both eyes at one month, Dr. Volpicelli said.

Overall impressions

Dr. Kantor, who contributed 25 eyes to the clinical trials, said he also performed his own patient satisfaction survey.
In the Norwood EyeCare clinical trial protocol, there is minimal medication for pain; Dr. McDonald’s new pain control regimen was not used, she said.
“Most of my patients have a little discomfort,” said Dr. Kantor, who ranked pain on a scale from 0 (no pain) to 10 (severe pain). “They probably are around four to seven as far as discomfort.”
Dr. Kantor also said that he, as a physician, is very comfortable with the procedure.
“I just didn’t feel very skillful in removing epithelium with a brush, with a scalpel, with alcohol,” Dr. Kantor said. “You name it, I’ve tried it. The Epikeratome is the best way I’ve had to remove epithelium.”
Nonetheless, Dr. Kantor said there is a steep learning curve when it comes to mastering the use of the Epikeratome. He said the quality of his epithelial sheets improved dramatically after watching the Epikeratome inventor, Ioannis G. Pallikaris, M.D., Ph.D., professor of ophthalmology, University of Crete, Greece, operate on patients with the device.
“With good training, you can make a good sheet,” Dr. Kantor said.
According to the clinical trials, 68% of attempted epithelial removals with the Epikeratome on 89 eyes achieved “complete separations,” which are the ideal type. Partial separations occurred in 15% of cases and free sheets occurred in 17% of cases. While a free sheet is “unhinged” it is replaceable, Dr. McDonald said.
“Creating a sub-optimal sheet in Epi-LASIK has completely different clinical impact that creating a suboptimal flap in LASIK,” she said. “In the former, the case becomes basically a hybrid of PRK and Epi-LASIK, and the outcome is excellent; In the latter, the clinical outcome can be disastrous.”
In fact, Dr. Kantor said of eight eyes he saw Dr. Pallikaris treat with the Epikeratome in Crete, the one with the best resulting vision had a free sheet. Nonetheless, Dr. Kantor said Dr. Pallikaris is extremely proficient with the Epikeratome device, and said it is important to try to create a good sheet of epithelium for good results.
Asked which patients he considers to be ideal for the Epi-LASIK procedure in light of the study results, Dr. Volpicelli said: Those that are “not good candidates for LASIK.”
These patients include older men and women (who are at higher risk for an epithelial slough or epithelial abrasion), patients with flat corneas, thin corneas, and basement membrane dystrophy. Anybody fearful of a corneal flap would also be good a good candidate, he said. h

Editors’ note: Dr. McDonald is medical monitor for the Centurion SES Epikeratome. Dr. Kantor was paid by Norwood Abbey for his participation in the Epikeratome clinical trials. Dr. Volpicelli has no financial interests related to his comments.

Contact Information
Kantor: 941-925-8888, rlkantor@kantoreye.com
McDonald: 504-896-1242, margueritemcdmd@aol.com
Volpicelli: 650-961-2585, drvopicelli@lasik2020.com