Ravalico 1994.

Methods	RCT. Open label.
Participants	26 paricipants with OHT. Racial constitution is not reported. Inclusion criteria: IOP between 22 and 30 mmHg, vision 20/20, cup/disc ratio below 0.5. Exclusion criteria: glaucoma within the family, narrow angle, other ocular pathologies.
Interventions	Levobunolol 0.5% twice daily. Untreated.
Outcomes	IOP. Change of visual field mean defect. Horizontal c/d ratio.
Notes	24 months follow up, but considerable attrition at 24 months. Drop‐out rate by 18 and 24 months: untreated group 7 and 11 of 23 eyes; levobunolol group 9 and 19 of 26 eyes (the number of participants who dropped out is not reported). The reasons for drop‐out are not detailed. The study appears to report mean values of both eyes where both eyes were included (most cases).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear