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Glaucoma and intraocular pressure in EPIC-Norfolk Eye Study: cross sectional study

BMJ 2017; 358 doi: https://doi.org/10.1136/bmj.j3889 (Published 13 September 2017) Cite this as: BMJ 2017;358:j3889
  1. Michelle P Y Chan, research fellow1,
  2. David C Broadway, professor3,
  3. Anthony P Khawaja, research fellow4,
  4. Jennifer L Y Yip, clinical lecturer4,
  5. David F Garway-Heath, professor5 6,
  6. Jennifer M Burr, reader7,
  7. Robert Luben, head of biomedical informatics4,
  8. Shabina Hayat, research coordinator4,
  9. Nichola Dalzell, study coordinator4,
  10. Kay-Tee Khaw, professor4,
  11. Paul J Foster, professor5 6
  1. 1Division of Genetics and Epidemiology, UCL Institute of Ophthalmology, London EC1V 9EL, UK
  2. 2Department of Ophthalmology, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich NR4 7UY, UK
  3. 3University of East Anglia, Norwich NR4 7TJ, UK
  4. 4Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
  5. 5NIHR Biomedical Research Centre Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
  6. 6UCL Institute of Ophthalmology, London EC1V 9EL, UK
  7. 7School of Medicine, Medical and Biological Sciences, University of St Andrews, St Andrews KY16 9TF, Scotland, UK
  1. Correspondence to: P Foster p.foster{at}ucl.ac.uk
  • Accepted 4 August 2017

Abstract

Objectives To report the distribution of intraocular pressure (IOP) by age and sex and the prevalence of glaucoma.

Design Community based cross sectional observational study.

Setting EPIC-Norfolk cohort in Norwich and the surrounding rural and urban areas.

Participants 8623 participants aged 48-92 recruited from the community who underwent ocular examination to identify glaucoma.

Main outcome measures Prevalence and characteristics of glaucoma, distribution of IOP, and the sensitivity and specificity of IOP for case finding for glaucoma.

Results The mean IOP in 8401 participants was 16.3 mm Hg (95% confidence interval 16.2 mm Hg to 16.3 mm Hg; SD 3.6 mm Hg). In 363 participants (4%), glaucoma was present in either eye; 314 (87%) had primary open angle glaucoma. In the remaining participants, glaucoma was suspected in 607 (7%), and 863 (10.0%) had ocular hypertension. Two thirds (242) of those with glaucoma had previously already received the diagnosis. In 76% of patients with newly diagnosed primary open angle glaucoma (83/107), the mean IOP was under the threshold for ocular hypertension (21 mm Hg). No one IOP threshold provided adequately high sensitivity and specificity for diagnosis of glaucoma.

Conclusions In this British community, cases of glaucoma, suspected glaucoma, and ocular hypertension represent a large number of potential referrals to the hospital eye service. The use of IOP for detection of those with glaucoma is inaccurate and probably not viable.

Footnotes

  • We thank Haogang Zhu for his help in extracting visual field data, Pak Sang Lee for his technical assistance with the EPIC-Norfolk Eye Study, and Ananth Viswanathan FRCOphth for providing one of the visual field analysers used in this study.

  • Contributors: MPYC analysed and interpreted the data and drafted the manuscript. PJF and DCB contributed to the conception and design of the study and to data collection. APK and JLYY contributed to data collection and interpretation. DGH contributed to the conception and design of the study and to data interpretation. JMB contributed to data interpretation. RL contributed to the design of the study and to data management. SH contributed to the design of the study. ND contributed to the design of the study and to data acquisition. KTK contributed to the conception and design of the study and to data interpretation. All authors read and critically revised the manuscript and approved the final manuscript. MPYC and PJF are guarantors.

  • Funding: EPIC-Norfolk infrastructure and core functions are supported by grants from the Medical Research Council (G0401527) and Cancer Research UK (C864/A8257). The clinic for the third health examination was funded by Research into Ageing (262). MPYC was supported by a joint Medical Research Council/Royal College of Ophthalmologists clinical training fellowship (G1001939/1) and the International Glaucoma Association. APK was a Wellcome Trust clinical research fellow (094791Z/10/Z). DGH, PJF, and JB were supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, and PF received additional support from The Richard Desmond Charitable Trust. The views expressed in the publication are those of the authors and not necessarily those of the Department of Health.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and report: DFG has received personal fees from Aerie, Alimera, Allergan, Quark, Quethera, Santen, Santhera, Sensimed, grants and personal fees from Alcon, Pfizer, and grants from NIHR i4i programme outside the submitted work, and has a patent contact lens tonometer pending; PJF reports an unrestricted grant from Alcon (US) and grants and personal fees from Allergan (UK) and Zeiss (EU); no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The work was approval by the East Norfolk and Waverney NHS research governance committee (2005EC07L) and the Norfolk research ethics committee (05/Q0101/191).

  • Data sharing: Requests for data sharing/access should be submitted to the EPIC Management Committee via Mrs Shabina Hayat (sah63{at}medschl.cam.ac.uk). Applications will be judged on a case by case basis, determined by the scientific merit, in line with MRC guidelines (https://www.mrc.ac.uk/publications/browse/mrc-policy-and-guidance-on-sharing-of-research-data-from-population-and-patient-studies/).

  • Transparency: The lead author (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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