Balamurali K. Ambati, MD, and Alan N. Carlson, MD
LASIK is now widely performed, with an estimated 1.5 million procedures performed last year.1 Flap complications have been reported in 5% to 8.7% of cases.2 The buttonhole, occurring at a rate of 0.3% to 2.6%, is one of the more serious flap abnormalities because it results in loss of BCVA.3-6
A buttonhole in the flap occurs when the microkeratome blade travels too superficially and breaches the central epithelial/Bowman's complex. A partial thickness buttonhole includes just the Bowman's layer; full thickness buttonholes occur when the blade exits anteriorly through the epithelium. A thin flap occurs when the keratome cuts within or anterior to Bowman's layer. This manifests with a shiny reflex on the stromal surface and can be recognized by a flap thickness of less than 60 µm (as the corneal epithelium is approximately 50 µm and Bowman's approximately 12 µm).
The complete article is available at www.reviewofrefractivesurgery.com/index.asp?page=6_6.htm
Posted by Admin at February 15, 2002 12:33 PM