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BCVA loss after re-treatment with surface ablation attributed to corneal scars
J Cataract Refract Surg. 2009;35(5):839-845.
Delayed re-treatment after aborted LASIK because of buttonholed flaps proved the best strategy for minimizing loss of best corrected visual acuity.
Buttonholed flaps may cause glare and significant loss of BCVA.
“The management of flap buttonholes is challenging and presents a therapeutic dilemma,” the study authors said. “Successful results have been reported by creating a new LASIK flap after 3 to 6 months. However, in cases in which the etiology of the buttonhole is unknown, a second keratectomy may lead to the development of a second buttonhole or other flap abnormality.”
The retrospective study included 17 eyes of 15 patients (mean age, 32.6 years) with buttonholed flaps. Eight eyes underwent laser ablation at the same time as buttonhole formation. LASIK was aborted in the remaining nine eyes.
Ten eyes underwent re-treatment; six eyes had repeat LASIK, three eyes underwent LASEK with mitomycin C and one eye underwent PRK. Re-treatment was a mean 20 weeks (range, 3 weeks to 47.1 weeks) after the initial LASIK attempt.
Eyes that underwent complete LASIK lost a mean 0.72 lines of BCVA. Eyes that had repeat LASIK lost a mean 0.62 lines. Eyes that underwent re-treatment with surface ablation lost a mean 0.8 lines. The higher loss of lines after surface ablation stemmed from ablation performed through a corneal scar, the authors said.
This is an excellent historical review that addresses a lot of the questions that people have about the incidence of buttonholes and discusses a lot of the potential causes. It shows that the incidence of buttonholes is extremely small, but it supports the conclusion of most people that the best approach is to abandon the surgery and not do laser ablation, then come back at a secondary date to do a repeat LASIK or surface ablation. One key thing is that if surface ablation is planned, that it should be done a few months afterward. But sometimes it is better not to wait a long time for the cornea to form a scar because it is harder to get a smooth surface.
Most people are moving toward femtosecond lasers, and buttonholes of this type do not occur with femtosecond lasers. They have other technical issues that need to be mastered. But over 50% of the procedures in the world are still done with a manual microkeratome, so I still think that this topic is pertinent.
Since I have not used a bladed microkeratome for the last 8 years, it does not affect me personally. But for the people that are still using manual microkeratomes, I think that the suggestion that if you have a thinner flap in the first eye, you should change blades for the second eye, was a very good suggestion. When I was using bladed microkeratomes, I always changed the blade for the second eye because complications in the second eye have been reported in this and other papers to be more common if you do not change the blade. Since they did have two cases that had bilateral buttonholes, it also points out that if you have something go wrong with the first eye, it is usually better to abort the whole procedure and not go on to the second eye at the same time.
– Daniel S. Durrie, MD
OSN Refractive
Surgery Section Editor