Salomão 2009.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: within person Number randomly assigned: 183 eyes, 183 participants Exclusions after randomization: 0 Number analyzed: 183 eyes, 183 participants Unit of analysis: eye Losses to follow‐up: 0 Handling of missing data: no missing data Power calculation: not reported Study dates: 2005 to 2007
Participants	Country: USA Overall mean age: 44 years (SD not reported) Age range: 20 to 72 years Gender: women 53.5%, men 46.5% Setting: Cole Eye Institute, Cleveland, OH Equivalence of baseline characteristics: yes Inclusion criteria: people with low‐to‐moderate myopia with no symptoms or signs of dry eye before LASIK Exclusion criteria: previous eye surgery, topical ocular medications before surgery, and other ocular conditions, such as ocular rosacea or chronic blepharitis
Interventions	Laser for ablation: Visx Star S4 IR or LADARWave 600 Intervention 1 Intervention: LASIK with a Hansatome microkeratome Flap dimensions: 180 μm thickness, 9.5 mm diameter, superior hinge Number of people randomized: 70 eyes, 70 participants Length of follow‐up: Planned: not reported Actual: 9 months Intervention 2 Intervention: LASIK with an IntraLase FS femtosecond laser Flap dimensions: 100 μm to 110 μm thickness, 9.0 mm to 9.3 mm diameter, and superior hinge Number of people randomized: 113 eyes, 113 participants Length of follow‐up: Planned: not reported Actual: 9 months
Outcomes	Adverse events reported: yes Dry eye Intervals at which outcome assessed: 1 day; 1 week; 1, 3, and 9 months Planned follow‐up: not reported Actual follow‐up: 9 months Scale: clinical grading scale Instrument for measurement: slit lamp examination
Identification	Sponsorship source: United States Public Health Service grants EY010056 and EY015638 from the National Eye Institute, Bethesda, Maryland, and Research to Prevent Blindness, New York, NY, USA Country: USA Setting: Institute of Ophthalmology Comments: none Author's name: Steven E Wilson Institution: Cole Eye Institute, I‐32, Cleveland Clinic Email: wilsons4@ccf.org Address: 9500 Euclid Avenue, Cleveland, OH 44195
Notes	Trial registration number: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "One eye of each patient was randomly chosen for inclusion in the trial." Comment: random component in the sequence generation not described
Allocation concealment (selection bias)	Unclear risk	Comment: trial did not address this risk of bias
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: trial did not address this risk of bias
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: trial did not address this risk of bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no missing outcome data
Selective reporting (reporting bias)	Unclear risk	Comment: no published trial protocol with which to compare
Other bias	Low risk	Comment: trial appeared free of other sources of bias