Egbert 2001.
| Methods |
Study design: parallel‐group, randomized controlled trial Number randomized (total and by group): Total: 92 eyes of 92 participants By group: 47 participants (Group 1, 1.5 W for 1.5 seconds) and 45 participants (Group 2, 1.25 W for 2.5 seconds) Exclusions after randomization: none reported Number analyzed (total and by group): Total: 79 eyes of 79 participants By group: 40 participants (Group 1) and 39 participants (Group 2) Unit of analysis: individual, 1 eye per person (worse eye if both eyes eligible) Losses to follow‐up: 13 of 92 participants (14%) How were missing data handled?: excluded from analysis Sample size calculation: not reported |
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| Participants |
Country: Ghana (Cape Coast and Accra) Mean age: 60.9 years Gender (number and percent): 56 (61%) men and 36 (39%) women Inclusion criteria: older than 20 years and having a diagnosis of primary open‐angle glaucoma (diagnosed by elevated IOP and glaucomatous disc cupping; exam also included gonioscopy, but not visual field testing) Exclusion criteria: previous glaucoma surgery, including argon laser trabeculoplasty, cataract extraction, or any other ocular surgery, or having no light perception Diagnosis: participants had “very advanced” primary open‐angle glaucoma; treated eye was the eye with more advanced glaucoma |
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| Interventions |
Group 1: 1.5 W for 1.5 seconds x 20 spots over 360 ° (45.0 J) Group 2: 1.25 W for 2.5 seconds x 20 spots over 360 ° (62.5 J) Retreatment: retreatment was at the discretion of the treating ophthalmologist; repeat treatment followed the original settings, but was limited to 15 spots over 270 ° Postoperative care: 4 mg of dexamethasone phosphate given subconjunctivally; atropine sulfate 1% applied twice daily and topical steroid applied 4 times daily; for a minimum of 3 weeks or until postoperative iritis resolved; use of glaucoma medications pre‐ or postoperatively was not standardized and may have been associated with variations in compliance Laser: OucLight SLx diode laser with a handheld G‐probe (IRIS Medical Instruments, Mountain View, California) Length of follow‐up: Planned: not reported Actual: mean 13.2 months; analysis included only participants with at least 3 months follow‐up |
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| Outcomes |
Primary outcome, as defined in study reports: (1) change in IOP and (2) reduction of medications Secondary outcomes, as defined in study reports: (1) change in visual acuity and (2) complications Adverse events reported: yes Intervals at which outcomes assessed: 1 day, 1 week, 3 weeks, and every 2 to 3 months |
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| Notes |
Trial registration: not reported Funding sources: Elsie B. Ballantyne Fund, Department of Ophthalmology, Standford University. IRIS Medical Instruments supplied the laser used in the study Disclosures of interest: not reported Study period: treatments administered February to August 1997 Reported subgroup analyses: none between treatment groups (only for total study population) |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: “We randomly assigned patients to receive 1 of 2 energy settings. After the retrobulbar anesthesia and just before treatment, a nurse tossed the coin to determine the settings.” |
| Allocation concealment (selection bias) | Low risk | Quote: “After the retrobulbar anesthesia and just before treatment, a nurse tossed the coin to determine the settings.” Participants were randomized while under anesthesia, so allocation would not have been known prior to enrollment in the trial |
| Masking of participants and personnel (performance bias) | Unclear risk | No information provided on masking of participants or personnel |
| Masking of outcome assessment (detection bias) | High risk | Quote: “Examiners were not masked to the treatment.” |
| Incomplete outcome data (attrition bias) All outcomes | High risk | 13 (14%) of 92 participants were excluded from analysis for all outcome measures, except for complications. In comparing those who were followed up for 3 months (and were included) with those who were not (excluded), the excluded were more likely to be male and more than 50 years old; preoperative IOP was similar between the 2 groups, but no postoperative IOP values were available. Comparisons between the treatment groups were not made for those that were not included in the analysis |
| Selective reporting (reporting bias) | Low risk | Results were reported for all outcomes specified in the Methods section of published report |
| Other bias | Unclear risk | The laser used in the trial was provided by the manufacturer. The trial was not registered prospectively. |
IOP: intraocular pressure J: joule mg: milligram W: watts