title: Anterior chamber gas bubble emergence pattern during femtosecond LASIK-flap creation.
abstract: OBJECTIVE
  To characterise the emergence pattern of cavitation bubbles into the anterior chamber (AC) following femtosecond laser-assisted in situ keratomileusis (LASIK)-flap creation
  
  
  METHODS
  Retrospective review of patients undergoing femtosecond LASIK surgery at Boston Laser, a private refractive surgery practice in Boston, Massachusetts, between December 2008 and February 2014. Patient charts were reviewed to identify all cases with gas bubble migration into the AC. Surgical videos were examined and the location of bubble entry was recorded separately for right and left eyes.
  
  
  RESULTS
  Five thousand one hundred and fifty-eight patients underwent femtosecond LASIK surgery. Air bubble migration into the AC, presumably via the Schlemm's canal and trabecular meshwork, occurred in 1% of cases. Patients with AC bubbles had an average age of 33±8 years with a measured LASIK flap thickness of 96±21 μm. The occurrence of gas bubbles impaired iris registration in 64% of cases. Gas bubbles appeared preferentially in the nasal or inferior quadrants for right (92% of cases) and left (100% of cases) eyes. This bubble emergence pattern is significantly different from that expected with a random distribution (p<0.0001) and did not seem associated with decentration of the femtosecond laser docking system.
  
  
  CONCLUSIONS
  The migration of gas bubbles into the AC is a rare occurrence during femtosecond laser flap creation. The preferential emergence of gas bubbles into the nasal and inferior quadrants of the AC may indicate a distinctive anatomy of the nasal Schlemm's canal.
authors.affiliation: Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Boston, Massachusetts, USA.
authors.forename: Marie-Claude
authors.identifier: http://orcid.org/0000-0001-7081-2870
authors.initials: MC
authors.lastname: Robert
authors.affiliation: Boston Eye Group, Brookline, Massachusetts, USA.
authors.forename: Nour
authors.initials: N
authors.lastname: Khreim
authors.affiliation: Boston Eye Group, Brookline, Massachusetts, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Todani
authors.affiliation: Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Boston, Massachusetts, USA Boston Eye Group, Brookline, Massachusetts, USA.
authors.forename: Samir A
authors.initials: SA
authors.lastname: Melki
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000473:pathology*; D003319:Corneal Stroma / Q000601:surgery; D004646:Emphysema / Q000209:etiology*; D005260:Female; D005740:Gases; D006801:Humans; D007431:Intraoperative Complications; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D054018:Lasers, Excimer / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D012189:Retrospective Studies; D013524:Surgical Flaps
chemical_list: D005740:Gases
keywords: Angle; Anterior chamber; Treatment Lasers