LASEK, PRK offer similar long-term outcomes for myopia

September 15, 2004

Difference in quality of vision seen in first week after LASEK procedure.

Dr. Pirouzian, a refractive surgeon with San Diego Children's Specialists, and the Refractive Center, in affiliation with University of California, San Diego, and his colleagues at the Travis Air Force Base, CA, conducted a prospective, randomized, double-masked clinical trial to assess the corneal clarity and visual acuity of patients treated with LASEK and PRK to determine if LASEK provides better outcomes in the long term.

"We found that LASEK and PRK for low- to-moderate myopia provide similar results in terms of visual acuity and corneal clarity," Dr. Pirouzian said. "But, there was a difference in the epithelial healing pattern immediately following surgery and in the quality of vision in the first week after the procedures. There seemed to be lower quality of vision in the first 48 hours after LASEK."

The LASEK procedure was accomplished with a mechanical method using 20% ethyl ethanol for 45 seconds. A micro-hoe was used to create the epithelial hinge. After ablation and replacement of the epithelium, a bandage contact lens was placed for 3 days postoperatively. Patients were prescribed ofloxacin 0.3% (Ocuflox, Allergan) q.i.d. for 3 days and ketorolac tromethamine 0.5% (Acular, Allergan) q.i.d. for 1 day postoperatively. After the contact lens was removed, fluorometholone ophthalmic suspension 0.1% (FML, Allergan) was used q.i.d. for 4 weeks for patients who had lower myopia ranging to -3 D and up to 3 months for patients who had higher levels of myopia in tapering fashion.

The PRK procedure was performed with the use of Amoils epithelial brusher. After ablation, the postoperative regimen of a bandage contact lens and eye drops was the same as with the LASEK procedure.

The mean spherical equivalent after each procedure was similar with 0.124 D for PRK and -0.0067 D for LASEK. The mean age was 29.4 years. At 1 year postoperatively, the mean visual acuity was also close for each procedure, with 1.55 for LASEK and 1.66 for PRK.

Final uncorrected visual acuity (UCVA) in the PRK group ranged from 20/15 to 20/30, with most patients seeing between 20/15 and 20/20. The final UCVA in the LASEK group was from 20/15 to 20/25, with most patients in the 20/15 to 20/20 range.

Quality of vision In the immediate postoperative period, all patients preferred the visual acuity in the PRK eyes. After 30 days postoperatively, half of the patients preferred the PRK eyes and half selected the LASEK eyes as providing the better quality of vision. After 1 year, PRK and LASEK were considered equally effective in terms of visual acuity, Dr. Pirouzian said.

In terms of side effects, only one patient with higher myopia experienced trace haze in both eyes-one treated with PRK and the other LASEK.

"The limitations of LASEK included increased surgical time with creation of the epithelial flap and early lower quality of vision in the first week after the procedure, probably due to the epithelial healing pattern immediately after surgery," Dr. Pirouzian said.