Abstract: Sixteen trials (1565 participants) met the inclusion criteria. Seven studies investigated some form of patient education. In six of these studies this education was combined with other behavioural change interventions including tailoring daily routines to promote adherence to eye drops. Eight studies compared different drug regimens (one of these trials also compared open and masked monitoring) and one study investigated a reminder device. The studies were of variable quality and some were at considerable risk of bias; in general, the length of follow-up was short at less than six months with only two studies following up to 12 months. Different interventions and outcomes were reported and so it was not possible to produce an overall estimate of effect. There was some evidence from three studies that education combined with personalised interventions, that is, more complex interventions, improved adherence to ocular hypotensive therapy. There was less information on other outcomes such as persistence and intraocular pressure, and no information on visual field defects, quality of life and cost. There was weak evidence as to whether people on simpler drug regimens were more likely to adhere and persist with their ocular hypotensive therapy. A particular problem was the interpretation of cross-over studies, which in general were not reported correctly. One study investigated a reminder device and monitoring but the study was small and inconclusive. Although complex interventions consisting of patient education combined with personalised behavioural change interventions, including tailoring daily routines to promote adherence to eye drops, may improve adherence to glaucoma medication, overall there is insufficient evidence to recommend a particular intervention. The interventions varied between studies and none of the included studies reported on the cost of the intervention. Simplified drug regimens also could be of benefit but again the current published studies do not provide conclusive evidence. Future studies should follow up for at least one year, and could benefit from standardised outcomes.

Plain-language summary: This review is based on 16 studies (1565 participants) that tried out different methods to help people to use drops as prescribed. All the studies took place in industrialised countries (Belgium, Denmark, France, Greece, Iceland, Japan, Sweden, Switzerland, UK and USA) and recruited participants in outpatient clinics. The following interventions were included: simplifying drop routines, reminder devices, automated telephone service, providing information about glaucoma and offering advice regarding day to day issues with eye care. Those studies which combined the provision of information about glaucoma and eye drops with other interventions, such as helping people to fit instillation of eye drops into their daily routine, appear to be more successful. Unfortunately, not all of these studies were of high quality and, therefore, until more evidence is available we cannot recommend any particular method. Good quality research is needed in this area in order to develop a better understanding of patients' individual needs and to help us provide more effective eye care services.