System promising for use in advanced surface ablation

October 15, 2005

Advanced surface ablation techniques offer potential advantages that make them attractive alternatives to LASIK for wavefront-guided procedures.

"There has been a movement back to the future in refractive surgery with a reappraisal of surface ablation techniques, and a number of devices for separating the epithelium without the cytotoxicity of alcohol are now available for use in these procedures. Despite their promise, where these new approaches fit into our armamentarium will depend on our ability to control pain, provide rapid visual rehabilitation, and prevent formation of haze when using them. Therefore, I think we need to work together to figure out safe and effective pharmaceutical regimens to help accelerate patient recovery with comfort after advanced surface ablation techniques," said Dr. O'Brien, who was The Tom Clancy Professor of Ophthalmology, Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, at the time of the study. Dr. O'Brien is now professor of ophthalmology, Charlotte Breyer Rodgers Distinguished Chair in Ophthalmology, and director of the refractive surgery service, Bascom Palmer Eye Institute of the Palm Beaches.

The EpiLift system received FDA approval for marketing in September 2004. Dr. O'Brien and colleagues at the Wilmer Eye Institute performed the first human procedure using this device.

The preliminary results showed excellent large-diameter, complete epithelial flaps were produced in 24 eyes. Two eyes-one with an incomplete partial epithelial flap and a second eye with a smaller-diameter flap-were converted to PRK.

The average time to TSCL removal was 4.1 days, but ranged from 36 hours to 7.2 days. The average pain score was 2.3 on a scale of 0 to 4, and four patients needed systemic narcotics. There was little to no haze.

Uncorrected visual acuity (UCVA) at day 1 averaged 20/50 and ranged from 20/25 to 20/200. The average UCVA at the time of TSCL removal was 20/30, and among patients seen at 3 months, 72% saw 20/20 or better.

So far, wavefront data were available from 16 eyes that underwent repeat aberrometry at 3 months.

The results showed a slight trend toward less total higher-order aberration RMS and less spherical aberration compared with historical controls that underwent CustomVue myopic LASIK, Dr. O'Brien reported.

Topical, oral treatments

Patients in this study received a number of different topical and oral treatments before, during, and after surgery to enhance outcomes and reduce complications. Oral vitamin C 2,000 mg/day was begun 1 week prior to surgery and continued for up to 4 weeks after surgery. The perioperative regimen consisted of topical anesthetic drops, a povidone-iodine prep, and a fourth-generation fluoroquinolone. Two eyes with higher myopia were treated with intraoperative mitomycin-C.

After surgery, all patients received a TSCL with an 8.9 base curve.

"The base curve of the contact lens seems to be important because use of a flatter base curve of 8.6 may lead to more corneal edema and breakdown of the central epithelium," Dr. O'Brien noted.