Manche_group 2008.
| Study characteristics | ||
| Methods |
Study design: randomized controlled trial Study grouping: within person Number randomly assigned: 102 eyes, 51 participants Exclusions after randomization: 16 eyes, 8 participants Number analyzed: 86 eyes, 43 participants Unit of analysis: eye Losses to follow‐up: 2 participants, 4 eyes Handling of missing data: eyes with missing data excluded from analysis Power calculation: not reported Study dates: May 2004 to November 2005 |
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| Participants |
Country: USA Overall mean age: 39.7 years (SD 7.8) Age range: 25 to 59 years Gender: women 69%, men 31% Setting: Department of Ophthalmology, Stanford University School of Medicine Equivalence of baseline characteristics: yes Inclusion criteria: people with no more than 6.00 D of spherical myopia, no more than 3.00 D of refractive astigmatism, stable refraction (0.50 D of sphere or cylinder), corneal diameter < 11.0 mm to allow for suction ring fixation, discontinuation of soft contact wear ≤ 7 days before the preoperative evaluation, visual acuity correctable to at least 20/20 in both eyes, age > 21 years, and ability to participate in follow‐up examinations for 12 months after LASIK Exclusion criteria: rigid gas‐permeable contact lens use; severe dry eye; severe blepharitis; anterior segment abnormalities (i.e. cataracts, corneal scarring, or neovascularization within 1 mm of the intended ablation zone); recurrent corneal erosion; severe basement membrane disease; progressive or unstable myopia or keratoconus; unstable corneal mires on central keratometry results; corneal thickness in which the LASIK procedure could result in < 250 μm of remaining posterior corneal thickness below the flap postoperatively; baseline standard manifest refraction exhibiting > 0.75 D more minus in sphere power or a difference > 0.50 D in cylinder power, or a different type of astigmatism, i.e. 'with‐the‐rule', 'against‐the‐rule', or 'oblique' when the cylinder was > 0.50 D compared with the baseline standard cycloplegic refraction; preoperative assessment of ocular topography or aberrations (or both) indicating that either eye is not a suitable candidate for the LASIK vision correction procedure (i.e. forme fruste keratoconus, corneal warpage, or pellucid marginal degeneration); previous intraocular or corneal surgery; history of herpes zoster or herpes simplex virus keratitis; current use of systemic corticosteroid or immunosuppressive therapy; immunocompromise or clinically significant atopic disease; connective tissue disease; diabetes mellitus; steroid response; macular abnormality; pregnancy or lactation; sensitivity to the planned trial concomitant medications; or participation in another clinical trial of an ophthalmic drug or device |
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| Interventions |
Laser for ablation: Star S4Excimer Laser System Intervention 1 Intervention: LASIK with a Hansatome microkeratome Flap dimensions: superiorly hinged, created using a 160 μm head and a 9.0 mm ring Number of people randomized: 51 eyes, 51 participants Length of follow‐up: Planned: not reported Actual: 12 months Intervention 2 Intervention: LASIK with an IntraLase femtosecond laser Flap dimensions: 120 μm thickness, 9.0 mm diameter, and superior hinge angle, degrees not reported Number of people randomized: 51 eyes, 51 participants Length of follow‐up: Planned: not reported Actual: 12 months |
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| Outcomes |
Mean spherical equivalent of the refractive error after surgery
Proportion of eyes within ± 0.5 D of target refraction after surgery
Adverse events reported: yes Corneal haze
Diffuse lamellar keratitis
Epithelial ingrowth
Dry eye
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| Identification |
Sponsorship source: not reported Country: USA Setting: Institute of Ophthalmology Comments: none Author's name: Edward E Manche Institution: Department of Ophthalmology, Stanford University School of Medicine Email: edward.manche@stanford.edu Address: 900 Blake Wilbur Drive, Third Floor, Stanford, CA 94305 |
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| Notes | Trial registration number: NCT00691431 | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "randomization was performed by assigning the dominant eye to one keratotomy method and the fellow eye to the other method according to a prepared randomization schedule." |
| Allocation concealment (selection bias) | Low risk | Quote: "envelope containing the assignment was opened." |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Quote: "The patient and the physician did not learn which eye would be treated with which keratome until the day of surgery." |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Comment: masking of outcome assessors not reported. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Quote: "Four patients (5 eyes) discontinued the trial 6 months after surgery or later and required retreatment with good outcomes. Two patients (4 eyes) were lost to follow‐up. Because of the excimer laser software upgrade after the first 8 patients underwent LASIK, only the remaining 43 patients are included in the refractive outcomes and patient preference analyses to rule out any issues related to the initial version of excimer laser software." |
| 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 |