From all Lasik flap complication, LASIK flap buttonholes are those that lead most frequently to lack of best-corrected visible acuity (BCVA). Why do they occur? Skinny, irregular and perforated flaps appear to outcome from a standard etiology; an insufficient coupling of the blade to the cornea. Steep corneas have been in comparison with tennis balls that may buckle centrally upon applanating stress. This ends in a central dimple missed by the blade resulting in a buttonhole. One other principle is that increased keratometric values supply elevated resistance to chopping when applanated, resulting in upwards motion of the blade 중절수술비용.

The latter might be extra relevant to keratomes with decrease oscillation charges. Equally, flat corneas could end in a skinny and/or small flap as they might be under the sufficient chopping stage in sure places. Insufficient blade to cornea coupling is commonly because of poor suction (sunken globe/small diameter corneas with insufficient suction ring placement, conjunctival incarceration within the suction port…). Non-angled blades have equal probabilities of shifting upwards in the direction of the floor or downwards in the direction of the stromal aspect if confronted with resistance. Alternatively, inferiorly angled blades usually tend to be pushed in the direction of the stroma. If a buttonhole is encountered (particularly centrally), most surgeons want to abort the process, substitute the flap and re lower a deeper flap (20-60 ?m deeper) roughly 10-12 weeks later. Whereas some advocate continuing with scraping the epithelium and performing a PRK laser ablation, we consider this strategy will not be possible in increased myopes because of the look of surprising haze.

A better index for epithelial ingrowth ought to maintained across the margins of the buttonhole. The incidence of perforated flaps (in addition to skinny and irregular ones) could also be decreased if the surgeon ensures sufficient suction, inspects the blades and adjusts the keratome plate thickness in keeping with corneal curvature. Different useful measures embody making certain sufficient intraocular stress earlier than chopping the flap. Measurement could also be Most worthy with a pneumotonometer as different means have been reported to offer imprecise readings at occasions. Care must be taken to keep away from conjunctival clogging within the suction port, which might result in discrepancy between the intraocular stress and the suction stress recorded on the microkeratome vacuum console. Newer microkeratomes have a security mechanism to robotically abort the process or to activate further suction however are additionally susceptible to comparable issues if IOP measurements will not be obtained to make sure sufficient suction. Some surgeons examine the microkeratome blade underneath the working microscope earlier than partaking it within the suction ring as a way to rule out manufacturing or different preoperative harm to the blade. It’s best to maintain the microkeratome away from arduous surfaces after meeting to keep away from subsequent blade harm.