LASIK, surface ablation are complementary procedures

LASIK provides quicker, less painful recovery, but surface ablation may be better suited for certain eyes, surgeon says.

LASIK and surface ablation can be considered complementary refractive surgical procedures, according to Scott M. MacRae, MD. LASIK is the more widely accepted procedure by far, but for patients with dry eye or thin corneas surface ablation may be preferred, he said.

Scott M. MacRae

“That’s how I use them in my practice,” he said, speaking at the American Academy of Ophthalmology meeting in Chicago. “Currently in my practice about 85% of patients are being treated with LASIK … and in 15% of cases I treat with surface ablation, and I really think [surface ablation] has a lot of utility.”

Although Dr. MacRae’s presentation was titled “Surface vs. lamellar: Which is best?” his conclusion was that “both LASIK and surface ablation provide excellent outcomes.”

He said there are advantages and disadvantages to each approach that surgeons must consider to decide which technique would be best for each patient.

“Surface ablation has become increasingly popular in the United States,” Dr. MacRae said. “Surface ablation has been found to be a very good treatment for patients with thin corneas, dry eyes and anterior basement membrane dystrophy, as well as for aviators in the military.”

LASIK widely accepted

LASIK is the procedure used in 90% of refractive surgical procedures today, Dr. MacRae said. It is widely accepted by patients and has good name recognition, and its clinical advantages are well-known, he said.

“The advantages of LASIK include quick visual recovery and the comfort of recovery,” he said. “There is a rapid return to function for work, driving and recreation. Typically, my patients can get back to doing what they normally do in life within 1 day after surgery.”

Follow-up for LASIK is also more convenient for both surgeon and patient, Dr. MacRae suggested.

“There are minimum weekend calls,” he said. “But when I perform surface ablation, it is not uncommon to receive Saturday morning calls from patients who underwent surgery on Thursday. Patients say their eye is stuck shut or is irritated.”

Some corneal complications seen with surface ablation are not an issue with LASIK, Dr. MacRae said.

“Normally, there are no problems with haze and re-epithelialization,” he said.

Disadvantages of LASIK can include flap complications such as interface keratitis and neurotropic dry eye due to the severing of corneal nerves, he said.

Surface advantages, disadvantages

Surface ablation procedures include PRK, laser epithelial keratomileusis (LASEK) and epi-LASIK, Dr. MacRae noted.

“It’s really unclear as to whether epi-LASIK is any different from PRK and LASEK in terms of outcomes or in terms of pain or inconvenience. So I’m going to lump them all together,” he said.

Advantages of surface ablation include less risk of corneal ectasia and no risk of flap complications, he said.

The surface procedures can be used to treat patients with thin corneas, especially those with higher myopia, he said.

“These patients can be successfully treated, especially with newer scanning lasers. If there is more than 5 D of myopia, I use mitomycin for 15 to 30 seconds,” he said.

For patients with moderate dry eye, surface ablation can also be the better option, he said.

Because there is no microkeratome involved, surface procedures can also be more appropriate in patients with tight or abnormal anatomies or very steep corneas, he said.

Another advantage of not using a microkeratome may be less induction of aberrations, Dr. MacRae said.

“Theoretically, if you don’t have a flap, you don’t end up with the higher-order aberrations that you induce with a flap,” he said. “Theoretically, the optics are better as well. The biomechanics are also superior because you are not removing as much corneal tissue.”

The disadvantages of surface ablation include slower visual recovery and slower return to work, driving and recreation, Dr. MacRae said.

“Most of these patients see reasonably well at 1 week, but sometimes it takes them 8 weeks before their vision truly makes a full recovery,” he said. “There is also more pain than with LASIK.”

In addition, because of the longer period of recovery there can be more patient anxiety postoperatively.

“After 1 to 3 days, they start having buyer’s remorse. You need to reassure them that things are going to get better,” Dr. MacRae said. “The slower recovery period is the biggest obstacle to surface ablation. It creates inconvenience and variability that we cannot predict to our patients.”

Surface ablation procedures also carry the possibility of complications, including corneal haze with subepithelial fibrosis, he said.

“Haze may develop underneath the epithelium, but this can be minimized,” Dr. MacRae said. “In my hands, clinically significant haze has been relatively uncommon because of the newer spot lasers and using mitomycin. However, re-treatments are more difficult. You need to scrape the epithelium. Recovery time from re-treatment is also longer.”

Thinner flaps

Dr. MacRae noted there has been a convergence between LASIK and surface ablation, with the increasing realization that thin LASIK flaps carry advantages.

“With greater accuracy and precision of the femtosecond laser and newer generation microkeratomes, we’re seeing improved safety and thinner flaps,” he said.

Other investigators have reported that patients with thinner flaps have improved postoperative visual results, Dr. MacRae said.

“Thinner flaps tend to minimize tissue removal and the neurotropic effect that we get with LASIK,” Dr. MacRae said. “I believe we will migrate toward trying to achieve better precision and accuracy using thinner flaps. If you have better precision, you can treat with a 110 µm to 100 µm flap.”

Investigators have observed that flap creation may cause an increase in higher-order aberration, he said.

“If the flap induces some aberration, why not try surface ablation and see if this helps reduce the increase in higher-order aberration?” Dr. MacRae said. This prospect has caused some clinicians to consider surface treatment more seriously, he noted.

For Your Information:

• Scott M. MacRae, MD, professor of ophthalmology and visual science at the University of Rochester, can be reached at Strong Vision, 100 Meridian Centre, Suite 125, Rochester, NY 14618; 585-341-7817; fax: 585-756-1975; e-mail: scott_macrae@urmc.rochester.edu.