Flap Buttonhole in Thin-Flap Laser In Situ Keratomileusis: Case Series and Review

Abstract

Formation of flap buttonhole is significantly more common in the second eye and with the usage of Moria M2 microkeratome and 90-microm blade. In thin-flap LASIK, the practice of using the same microkeratome blade for the fellow eye, as is commonly followed at many refractive surgery centres, should be abandoned. Intraoperative subtraction pachymetry may be helpful in predicting the risk of buttonhole in the second eye. These precautions are especially mandatory in thin-flap LASIK irrespective of the other associated risk factors.

Hydrogel sealant to prevent recurrent epithelial ingrowth in the setting of a LASIK flap buttonhole

“…Most surgeons recommend waiting a period of time and then either making a deeper flap cut for LASIK or, more commonly, changing to a surface ablation approach. For example, some have described protocols involving photorefractive keratectomy (PRK) with mitomycin C, some preceded by phototherapeutic keratectomy (PTK) and others preceded by epithelial treatment with alcohol 5 , 8 , 14 , 15 . Some advocate for early surface ablation before haze, scarring, or epithelial ingrowth are significant, while others advise waiting several months to allow the refraction to stabilize 2 , 16, 17, 18, 19.…”

“…One potential complication of LASIK flap creation is buttonhole formation, where an irregular lamellar cut results in a connection between the plane of the flap and the corneal surface. The incidence of buttonhole formation has been reported to range from 0.07% to 1.74% with mechanical microkeratomes and has become even less common with the use of femtosecond laser flap creation 1, 2, 3, 4, 5, 6, 7, 8. Nevertheless, it is a feared complication as it can result in epithelial ingrowth, which can lead to irregular astigmatism, flap melt, and loss of visual acuity.…”

Complications of laser-assisted in situ keratomileusis

“…3b ] It is observed in 0.03% to 2.6% of cases. [ 18 ] Steep cornea (>48 D), suction loss, large flap, second eye, m-LASIK, and vertical gas breakthrough (VGB) in FS-LASIK are the reported risk factors. [ 18 19 ] Management includes aborting the procedure and planning for re-treatment, preferably surface ablation after three months.…”

“…[ 18 ] Steep cornea (>48 D), suction loss, large flap, second eye, m-LASIK, and vertical gas breakthrough (VGB) in FS-LASIK are the reported risk factors. [ 18 19 ] Management includes aborting the procedure and planning for re-treatment, preferably surface ablation after three months. [ 18 19 ] In case, LASIK is performed, the flap should be of a larger diameter and greater thickness.…”

Femtosecond LASIK Flaps: Excellent, but Superior?

“…These almost always occur in the second eye with a thinner fl ap in mechanical microkeratomes. 14,15 Femtosecond laser fl aps are also prone to similar complications of variable severity, [16][17][18] albeit usually from a different mechanism: vertical gas breakthrough. In this issue, Tomita and colleagues 19 report a series of eyes undergoing LASIK with anterior stromal opacities, fi nding that the Femto LDV (Ziemer Ophthalmic Systems AG) created signifi cantly thinner fl aps without experiencing vertical gas breakthrough, whereas the IntraLase FS 60 had equal acuity outcomes but a signifi cantly higher number of vertical gas breakthrough cases.…”