Holmwood 1992.

Methods	Study design: parallel‐group RCT Country: US Number randomized: Total: 60 Per group: apraclonidine before and after = 30, apraclonidine only after = 30 Exclusions after randomization: not reported Number analyzed: Total: 60 Per group: apraclonidine before and after = 30, apraclonidine only after = 30 Unit of analysis (participants vs eyes): participant (1 eye per participant) Losses to follow‐up: none reported How was missing data handled?: N/A Reported power calculation: no
Participants	Age: not reported Females: not reported Inclusion criteria: people who had POAG, defined by optic disk cupping and visual field loss, and a pretreatment IOP > 21 mmHg on maximally tolerated medical therapy Exclusion criteria: previous intraocular surgical procedures or laser treatment, people who had secondary OAG (e.g. pigmentary, exfoliative, or uveitic), and aged < 40 years Equivalence of baseline characteristics: yes, "There were no statistical differences between preoperative IOP and the number of antiglaucoma medications between the two groups of patients."
Interventions	Intervention 1: 1 drop apraclonidine 1%, 1 hour before and immediately after 360° LTP Intervention 2: 1 drop apraclonidine 1%, only after 360° LTP Length of follow‐up: Planned: 2 hours Actual: 2 hours
Outcomes	Primary outcome: IOP Secondary outcomes: not reported Adverse events reported: no Intervals at which outcomes assessed: baseline; 1, 2 hours after treatment
Notes	Trial registration: not reported Funding sources: "This study was supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York." Disclosures of interest: none reported Study period: not reported Reported subgroup analyses: no
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"One of the following two apraclonidine open‐label treatment regimens was determined from a random table chart…"
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported.
Masking of participants and personnel (performance bias)	High risk	Study was open‐label and no mention of vehicle drops, so participants would be aware whether they received drops before and after surgery or only after surgery.
Masking of outcome assessment (detection bias)	Low risk	"Intraocular pressure was measured one and two hours after treatment by an observer who was masked to the random assignment to treatment with apraclonidine."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear whether there were any missing data or how they were handled.
Selective reporting (reporting bias)	Unclear risk	Unclear whether there was selective outcome reporting.
Other bias	Low risk	None