Gandolfi 1996.

Study characteristics
Methods	Study design: paired‐eye, randomized controlled trial Number randomly assigned: 52 eyes of 26 participants; the fellow eye of each participant was the control Exclusions after randomization: none reported Losses to follow‐up: 5 participants; 1 participant died in a motor vehicle accident and 4 participants requested an iridotomy in the fellow eye at an outside clinic Number analyzed: 42 eyes of 21 participants Unit of analysis: eye (both eyes per participant) Handling of missing data: excluded from analysis Sample size and power calculation: Trial authors reported that the analyzed sample size was adequate to reveal a difference of 45% in IOP with 95% power and type I error of 0.05. This seems to be post hoc power calculation, but no clear information is available
Participants	Country: Italy Mean age: not reported (range 19 to 60 years); not reported by group Gender: 14 (67%) men and 7 (33%) women; not reported by group Inclusion criteria: referral to the authors’ glaucoma service and diagnosed with pigment dispersion syndrome in both eyes. Diagnosis was made if pigment was deposited on the corneal endothelium in both eyes, at least 1 slit‐like mid‐peripheral transillumination defect was noted in the iris of both eyes, brownish pigment was deposited on the angle structures at greater than 270 degrees for both eyes, IOP was less than 18 mmHg in both eyes, pigment was liberated into the anterior chamber with topical phenylephrine in both eyes, visual field defects were absent in both eyes Exclusion criteria: not reported Equivalence of baseline characteristics: not reported
Interventions	Laser: iridotomy with an yttrium–aluminum–garnet (YAG) laser, after which each participant was administered 1 drop of dexamethasone and 1 tablet of 250 mg acetazolamide Control: no treatment Length of follow‐up: Planned: 2 years Actual: 2 years, with extended follow‐up at 10 years
Outcomes	Primary outcome, as defined by the trial: proportion with "stable IOP," defined as IOP not increasing more than 5 mmHg; IOP calculated as an average of the 2 highest readings from the diurnal curve by Goldmann applanation tonometry Secondary outcomes, as defined by the trial: difference in IOP between treated eye and untreated fellow eye vs age; difference in IOP between treated eye and untreated fellow eye vs refractive error; refraction measured after cycloplegia (1% tropicamide, 1 drop every 5 minutes for 15 minutes) Safety measures, as defined by the trial: loss of visual acuity, lens transparency, and visual field; progression of optic nerve head damage Intervals at which outcome assessed: every 6 months for 2 years, and at 10 years Information on cost of interventions or quality of life: none reported
Notes	Study period: not reported Trial registration: none reported Source of funding: research grants from M. U. R. S. T., Rome, Italy Disclosures of interest: "The authors have no proprietary interest in any of the materials used in this study" Subgroup analyses: none reported; however, age and refractive error were plotted against IOP change for assessment of correlation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomization not reported. "An iridotomy was performed by the same investigator (SAG) in the randomly chosen eye after instillation of one drop of 0.2% dexamethasone"
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not reported
Masking of outcome assessors (detection bias) Visual field	Unclear risk	Masking of visual field examiners not reported
Masking of outcome assessors (detection bias) Intraocular pressure	Low risk	"The follow‐up was performed by measuring ("masked observer") the daily IOP curve (from 8:00 AM to 6:00 PM, 6 readings, 1 reading every 2 hours) every 6 months"
Incomplete outcome data (attrition bias) All outcomes	High risk	Excluded data from 5 of 26 (19%) participants, 4 of which were based on treatment group
Selective reporting (reporting bias)	High risk	The 10‐year results paper specified safety outcomes (visual acuity, lens transparency, optic nerve head, and visual field) that were not reported in the 2‐year results paper. Further, visual acuity and optic nerve head outcomes were not reported in the 10‐year results paper
Other bias	Low risk	None identified