Lenticule extraction found effective for patients with myopia and myopic astigmatism
His statement was based on analysis of outcomes in a series of 94 eyes followed for up to 1 year after undergoing the proprietary refractive procedure (ReLEx, Carl Zeiss Meditec) that is based on tissue removal rather than ablation.
"There is only a small learning curve for performing this procedure, it is very comfortable for patients, complications occur rarely and have been nonvision threatening, and only a single instrument, a femtosecond laser (VisuMax) is needed for the refractive procedure," said Dr Graue-HernÁndez, head, Department of Cornea and Refractive Surgery, Institute of Ophthalmology, Conde de Valenciana, Mexico City, Mexico.
Patients were eligible for inclusion in the study if they had up to –10 D of myopia and up to –5 D cylinder, had demonstrated refractive stability for at least 1 year, and would otherwise be considered candidates for LASIK based on their pachymetry, topography and estimated residual stromal bed thickness.
The patients had a mean age of 27 years (range 18 to 46 years), manifest refractive spherical equivalent (MRSE) of –4.34 D (range to –8 D), mean sphere of –3.26 D (range to –6.75 D), and mean cylinder of –1.5 D (range to –5 D). Twelve eyes were eliminated from the efficacy analysis because the lenticule could not be lifted; these patients underwent femto-LASIK instead. All of the remaining 82 eyes were seen at 1 day and 1 week after surgery, 74 eyes were seen for follow-up at 1 month, 49 eyes at 6 months and 22 eyes completed 1 year of follow-up.
The analysis of refractive results showed achieved mean MRSE at 1 week was close to plano (0.17 ± 0.74 D). Over time, there was a trend toward a myopic shift, and mean MRSE at 1 year was –0.27 ± 0.82 D. Only 4% of eyes followed from 3 to 12 months, however, had a refractive change >0.5 D.
At 1 month, achieved MRSE was within 1 D of attempted in 85% of eyes and within 0.5 D in 70%. The results for predictability of the cylinder correction were similar. Distance UCVA was 20/40 or better in 99% of eyes at 1 month, although only 46% saw 20/20 or better, Dr Graue-HernÁndez noted.
Safety was good, and no eyes lost more than 1 line of best-corrected visual acuity (BCVA), while 80% remained the same and only 11% gained 1 line.
Aside from the inability to lift the lenticule, complications encountered intraoperatively included two cases (2.1%) in which the lenticule remained on the flap - which Dr Graue-HernÁndez characterized as a learning curve issue - and one case where the lenticule was broken at the edge. There were no cases of suction loss or epithelium breaches during the procedure, he noted.
Dry eye (11.7%) was the most common complication during postoperative follow-up. Striae developed in two eyes (2.1%), mild haze in one eye (1.1%), and stromal opacities in four eyes (4.2%).
"The opacities could take a very long time to fade away, but they did not seem to bother the patient or lead to complaints," Dr Graue-HernÁndez said.
In addition, the treatment was decentred in one case and resulted in high mixed astigmatism, he noted. The involved patient was the only one in the series that had a 1-line loss of BCVA.
Dr Enrique Graue-HernÁndez, MD, is head of the Department of Cornea and Refractive Surgery, Institute of Ophthalmology, Conde de Valenciana, Mexico City, Mexico. He may be reached by E-mail: firstname.lastname@example.org
Dr Graue-HernÁndez has indicated no financial interests in the subject matter.