Evolving techniques reduce pain, haze associated with surface ablation

Nonsteroidals and intraoperative mitomycin C speed visual recovery and prevent complications, surgeons say.

Surface ablation has traditionally involved more postoperative pain, slower visual recovery and more postoperative haze than LASIK. However, advanced surface ablation techniques have optimized visual outcomes and raised safety profiles, surgeons say.

Advanced surface ablation encompasses PRK, epi-LASIK and LASEK, but advanced PRK has moved to the forefront because epi-LASIK and LASEK entail slower epithelial healing, a significantly greater risk of infection and slower visual recovery, OSN Refractive Surgery Board Member Kerry D. Solomon, MD, said.

“We found absolutely no benefit to a LASEK technique, which is why in my practice we’ve moved entirely to PRK, or what we call ‘advanced surface ablation,’” Dr. Solomon said.

In addition, wavefront-driven profiles markedly enhance visual outcomes in advanced surface ablation, Dr. Solomon said.

“The military has certainly shown that to be a more precise and more effective way to treat vision,” he said. “The profile is such that they are designed to reduce night vision symptoms and to provide an overall better quality of vision. This is probably due to the lower amount of higher-order aberrations that are induced by the treatments themselves.”

Ronald K. Krueger, MD, also prefers PRK over other techniques.

“In my opinion, LASEK has declined some and epi-LASIK is performed by a handful,” Dr. Krueger said. “Personally, I have made PRK the surface procedure of choice and perform all my surface cases this way.”

William B. Trattler

Dr. Krueger said PRK profiles can yield even better visual outcomes than femtosecond LASIK.

“My 20/20 rates with optimized PRK are even better than my 20/20 rates with optimized IntraLASIK,” he said.

Advanced surface ablation is a viable surgical alternative for patients who are not good candidates for LASIK, such as those with corneal pathology and suspect topography, William B. Trattler, MD, OSN SuperSite Board Member, said.

“I’m choosing surface ablation for patients that are not eligible for LASIK but want refractive surgery and where we can do PRK,” Dr. Trattler said. “For me, [indications are] going to be corneal opacities, irregular forme fruste keratoconus or any suspicious corneas.”

Managing postop pain

Ethyl alcohol is commonly used to remove the epithelium before surface ablation is performed.

“I don’t know why, but in my own experience and others’, if you use alcohol to remove the epithelium as opposed to just manual debridement, patients seem to have and notice less pain,” Dr. Solomon said.

Nonsteroidal drugs, bandage contact lenses, analgesics and chilled balanced salt solution are also used to minimize postoperative pain, he said.

Acuvail (preservative-free ketorolac tromethamine ophthalmic solution 0.45%, Allergan), a new preservative-free formulation of ketorolac indicated for the treatment of pain after cataract surgery, is particularly effective, Dr. Solomon said.

“It’s gentle to the epithelium yet it penetrates much more potently into the cornea and into the eye,” he said. “And there’s twice daily dosing. It’s well-tolerated by the patients with no burning or stinging. It’s more effective in terms of reducing pain.”

Vistakon’s Acuvue and other bandage contact lenses are also beneficial, he said.

Preservative-free topical Alcaine (proparacaine hydrochloride, Alcon) has also proven effective in minimizing pain. Patients are typically directed to use the agent four to six times daily or as needed.

“It’s rare that patients use it that often, but it has tremendously helped with discomfort,” Dr. Solomon said. “In fact, patients really don’t have pain. It’s been interesting that after 24 hours, patients rarely need to use it anywhere.”

Dr. Trattler said he uses either Acuvail or Xibrom (bromfenac ophthalmic solution 0.09%, Ista Pharmaceuticals) twice daily, and also provides topical anesthetics (dilute tetracaine and/or proparacaine hydrochloride) for use by patients only if they experience significant discomfort.

Some surgeons recommend applying ice-cold balanced salt solution immediately after laser treatment to reduce postoperative pain after advanced surface ablation.

A sponge soaked with mitomycin C 0.02% is applied to the cornea for 12 seconds during advanced surface ablation to prevent late-onset postoperative haze. Images: Trattler WB

Chilled balanced saline solution is also effective in reducing pain, Dr. Trattler said. The frozen solution is typically applied to the eye for 30 seconds immediately following the ablation.

Dr. Trattler said the use of Restasis (cyclosporine ophthalmic emulsion, Allergan) and/or punctal plugs helps to optimize the ocular surface preoperatively.

“We want to make sure we do everything we can to have a very healthy tear film, which is critical for speeding epithelium healing,” Dr. Trattler said.

Dr. Krueger said he uses properly fitted contact lenses, Acular (ketorolac tromethamine ophthalmic solution 0.5%), oral Percocet (oxycodone and acetaminophen, Endo Pharmaceuticals), and slightly chilled, not ice-cold, balanced salt solution to mitigate postoperative pain.

Pain is frequently not an issue with advanced surface ablation, Dr. Krueger said.

“I think postop pain is a variable thing. I tell my patients to expect some pain and, surprisingly, less than half of them really say they notice much of anything, and I’m not doing anything special,” Dr. Krueger said.

Minimizing haze

Mitomycin C is currently the gold standard for minimizing postoperative haze, Dr. Solomon said.

“I think mitomycin C has become pretty much standard of care,” he said. “The goal of the mitomycin C is to prevent any visually significant corneal haze that can occur.”

Formerly, MMC was applied for 2 minutes but is currently applied for 15 to 30 seconds, Dr. Solomon said.

MMC is effective in preventing late-onset postoperative haze, which typically occurs 1 or 2 months postoperatively, Dr. Trattler said.

“If your patient experiences a delay in epithelial healing and develops early haze, the best treatment appears to be topical steroids. The use of intraoperative mitomycin does not appear to prevent early haze from developing,” Dr. Trattler said. “MMC only prevents the late-onset haze, which appears to be related to UV exposure. MMC helps prevent the activation of collagen fibers in the cells, which leads to haze.”

Dr. Krueger prefers using MMC in cases that involve more than 3 D of correction.

“As far as preventing problems, haze is the biggest-volume type of concern that can happen,” Dr. Krueger said. “That can happen sometimes with delayed epithelialization. But also with higher corrections, where the surface sometimes gets rougher, you can get haze. That’s where mitomycin comes in. The ideal concentration is 0.02%. We have tried using a tenfold lower percent concentration, 0.002%, but the incidence of haze was statistically higher, so we went back to the standard dosage.” – by Matt Hasson

References:

• Blake CR, Cervantes-Castañeda RA, Macias-Rodríguez Y, Anzoulatous G, et al. Comparison of postoperative pain in patients following photorefractive keratectomy versus advanced surface ablation. J Cataract Refract Surg. 2005;31(7):1314-1319.
• Randleman JB, Loft ES, Banning CS, Lynn MJ, et al. Outcomes of wavefront-optimized surface ablation. Ophthalmology. 2007;114(5):983-988.
• Thornton IL, Xu M, Krueger RR. Comparison of standard (0.02%) and low dose (0.002%) mitomycin C in the prevention of corneal haze following surface ablation for myopia. J Refract Surg. 2008;24(1):S68-S76.
• Trattler WB, Barnes SD. Current trends in advanced surface ablation. Curr Opin Ophthalmol. 2008;19(4):330-334.

• Ronald K. Krueger, MD, can be reached at the Cleveland Clinic Foundation, 9500 Euclid Ave., Room i32, Cleveland, OH 44195; 216-444-8158; fax: 216-445-8475; e-mail: Krueger@ccf.org.
• Kerry D. Solomon, MD, can be reached at Carolina Eyecare Physicians, 1280 Johnnie Dodds Blvd., Suite 100, Mt. Pleasant, SC 29464; 843-881-3937 or 888-849-3937; fax: 843-884-8587; e-mail: kerry.solomon@carolinaeyecare.com.
• William B. Trattler, MD, can be reached at 8940 N. Kendall Drive, #400, Miami, FL 33176; 305-598-2020; fax: 305-274-0426; e-mail: wtrattler@gmail.com. Dr. Trattler is a paid consultant for Allergan and ISTA Pharmaceuticals.