Tan 2007.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: within person Number randomly assigned: 82 eyes, 41 participants Exclusions after randomization: 0 Number analyzed: 82 eyes, 41 participants Unit of analysis: eye Losses to follow‐up: 0 Handling of missing data: no missing data Power calculation: not reported Study dates: not reported
Participants	Country: Singapore Overall mean age: 31,4 (SD 5.3) Age range: 21 to 42 years Gender: women 82.9%, men 17.1% Setting: The Eye Institute at Tan Tock Seng Hospital Equivalence of baseline characteristics: Yes Inclusion criteria: "All participants had not undergone any previous ocular surgery to either eye" Exclusion criteria: "...were excluded from the trial if they had serious preexisting ocular pathology"
Interventions	Laser for ablation: Technolas Z100 Excimer laser Intervention 1 Intervention: LASIK with a Zyoptix XP microkeratome Flap dimensions: 120 μm thickness, 8.5 mm diameter, superior hinge Number of people randomized: 41 eyes, 41 participants Length of follow‐up: Planned: not reported Actual: 1 day Intervention 2 Intervention: LASIK with a Intralase laser Flap dimensions: 120 μm thickness, 8.5 mm diameter, superior hinge Number of people randomized: 41 eyes, 41 participants Length of follow‐up: Planned: not reported Actual: 1 day
Outcomes	Light perception Intervals at which outcome assessed: during the procedure (suction, fashioning of flap) Planned follow‐up: not reported Actual follow‐up: 1 day Scale: Analog scale from 0 to 10 Instrument for measurement: standardized questionnaire (name or reference not reported)
Identification	Sponsorship source: not reported Country: Singapore Setting: Institute of Ophthalmology Comments: none Author's name: Hung‐Ming Lee Institution: The Eye Institute, Tan Tock Seng Hospital Email: Hung_Ming_Lee@ttsh.com.sg Address: 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
Notes	Trial registration number: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	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	Unclear 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