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Missed opportunity from randomised controlled trials of medical interventions for open-angle glaucoma
  1. Andrew Law1,
  2. Kristina Lindsley1,
  3. Benjamin Rouse1,
  4. Richard Wormald2,
  5. Kay Dickersin1,
  6. Tianjing Li1
  1. 1Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
  2. 2London School of Hygiene and Tropical Medicine, London, UK
  1. Correspondence to Dr Tianjing Li, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, E6011 Baltimore, MD 21205, USA; tli19{at}


Purpose To evaluate the extent to which intraocular pressure and visual field have been reported as outcomes in randomised controlled trials (also referred to as ‘trials’) of medical treatments for open-angle glaucoma.

Methods We identified published reports of trials in a systematic review of medical interventions for open-angle glaucoma our group conducted. We assessed whether intraocular pressure and visual field were reported as trial outcomes and classified them to be either completely or incompletely reported for meta-analysis. We also collected data on the length of time patients were followed and source of funding for the trial.

Results As of March 2014, we identified 401 trials that had enrolled 76 861 participants. Eighty per cent of 401 trials provided complete information on intraocular pressure and 11% of the 401 trials provided complete information on visual field. Only a minority of trials followed patients for at least 1 year. About half of all reports in our study stated that receiving funding from the industry.

Conclusions Although the vast majority of trials provided sufficient data for meta-analysis of the effect of medical management of open-angle glaucoma on intraocular pressure, relatively few provided data for analysing the effect on visual field. We considered this as missed opportunity because the data were not available for evidence synthesis. Investigators have an obligation to patients and providers to determine the comparative effectiveness of glaucoma interventions in terms of patient-important outcomes and not to waste data that could have been collected in trials.

  • Clinical Trial
  • Epidemiology
  • Glaucoma
  • Intraocular pressure
  • Public health

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  • Meeting Presentation: The 23rd Cochrane Colloquium, Vienna, Austria, 2015

  • Contributors All co-authors contributed equally to the manuscript.

  • Funding The project was funded by Grant 1 RC1 EY020140 and Grant 1 U01 EY020522, National Eye Institute, National Institutes of Health, USA (PI: Dr Kay Dickersin). RW, Co-ordinating Editor for Cochrane Eyes and Vision (CEV), acknowledges financial support for his CEV research sessions from the Department of Health through the award made by the National Institute for Health Research to Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology for a Specialist Biomedical Research Centre for Ophthalmology.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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