title: Opaque bubble layer incidence in Femtosecond laser-assisted LASIK: comparison among different flap design parameters.
abstract: The purpose of this study was to evaluate the incidence of opaque bubble layer (OBL) in femtosecond laser-assisted in situ keratomileusis (LASIK) flaps created with the support of Visumax Carl Zeiss femtosecond laser, planned with different flap diameters (7.90, 8.0, and 8.20 mm) and the same laser energy and power settings. Incidence of intraoperative OBL in flaps of consecutive 108 patients (216 eyes) subjected to bilateral femtosecond-assisted LASIK was considered. Flap creation was performed with the same laser design parameters (spot distance and energy offset) and different presetting diameters of 7.90 mm (72 eyes, group 1), 8 mm (72 eyes, group 2), and 8.20 mm (72 eyes, group 3). The incidence of OBL was considered and its extension was reported measuring involvement of different four corneal flap quadrants in which was theoretically divided the entire flap area; based on these data, OBL presence was classified as none (no evidence of OBL), minimal (minimal presence in not more that one quadrants corneal flap), mild (OBL presence in almost two or three quadrants without tendency to invade central cornea), and moderate (OBL presence in almost three quadrants with tendency to invade central cornea). In group 1, the incidence of OBL was of 23.6 % (17 eyes) with a mild/moderate presence; in group 2, incidence was 20.8 % (15 eyes) with mild presence. Group 3 presented a reduced OBL incidence (4.1 %, 3 eye) with a minimal presence. No statistically significant difference was found between group 1 and 2 (p = 0.8414).We found statistically significant differences between group 1 and group 3 (p = 0.0012) and between groups 2 and 3 (p = 0.0044). A significant reduction and extension of OBL incidence were evident when LASIK flap settings diameter was increased, and flap edge was closer to the contact glass border; this is probably consequent to a more effective gas dispersion outside of corneal flap.
authors: Department of Medicine and Ageing Sciences, Ophthalmology Clinic. University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy.
authors: Leonardo
authors: L
authors: Mastropasqua
authors: Department of Medicine and Ageing Sciences, Ophthalmology Clinic. University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy. roberta.calienno@gmail.com.
authors: Roberta
authors: R
authors: Calienno
authors: Department of Medicine and Ageing Sciences, Ophthalmology Clinic. University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy.
authors: Manuela
authors: M
authors: Lanzini
authors: Department of Medicine and Ageing Sciences, Ophthalmology Clinic. University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy.
authors: Niccolò
authors: N
authors: Salgari
authors: Carl Zeiss S.p.A., Refractive Service, Milan, Italy.
authors: Sergio
authors: S
authors: De Vecchi
authors: Ophthalmic Clinic of Verona, Verona, Italy.
authors: Rodolfo
authors: R
authors: Mastropasqua
authors: Department of Medicine and Ageing Sciences, Ophthalmology Clinic. University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy.
authors: Mario
authors: M
authors: Nubile
mesh_terms: D000328:Adult; D000368:Aged; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D012029:Refraction, Ocular; D012189:Retrospective Studies; D013524:Surgical Flaps; D016896:Treatment Outcome; D014792:Visual Acuity
keywords: Femtosecond laser; LASIK; Opaque bubble layer; Refractive surgery