Objective This study aimed to demonstrate that large-scale visual field (VF) data can be extracted from electronic medical records (EMRs) and to assess the feasibility of calculating metrics from these data that could be used to audit aspects of service delivery of glaucoma care.
Method and analysis Humphrey visual field analyser (HFA) data were extracted from Medisoft EMRs from five regionally different clinics in England in November 2015, resulting in 602 439 records from 73 994 people. Target patients were defined as people in glaucoma clinics with measurable and sustained VF loss in at least one eye (HFA mean deviation (MD) outside normal limits ≥2 VFs). Metrics for VF reliability, stage of VF loss at presentation, speed of MD loss, predicted loss of sight years (bilateral VF impairment) and frequency of VFs were calculated.
Results One-third of people (34.8%) in the EMRs had measurable and repeatable VF loss and were subject to analyses (n=25 760 patients). Median (IQR) age and presenting MD in these patients were 71 (61, 78) years and −6 (–10, –4) dB, respectively. In 19 264 patients with >4 years follow-up, median (IQR) MD loss was −0.2 (−0.8, 0.3) dB/year and median (IQR) intervals between VF examinations was 11 (8, 16) months. Metrics predicting loss of sight years and reliability of examinations varied between centres (p<0.001).
Conclusion This study illustrates the feasibility of assessing aspects of health service delivery in glaucoma clinics through analysis of VF databases. Proposed metrics could be useful for blindness prevention from glaucoma in secondary care centres.
- visual fields
- electronic medical records
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Contributors SRK: design, analysis and interpretation of data, drafting the article, revising the article. SRB: design, analysis and interpretation of data, drafting the article. JS: conception, design, revising the article. DPC: conception, design, interpretation of data, drafting the article, revising the article.
Funding Data were electronically extracted from contributing hospitals by the Royal College of Ophthalmologists audit team as part of the Healthcare Quality Improvement Partnership commissioned National Ophthalmology Database Audit (which forms part of the National Clinical Audit and Patient Outcomes Programme). SRK received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 675033. The listed funding organisations had no role in the design or conduct of this research.
Competing interests DPC reports speaker fees from Allergan, Bayer, Santen; unrestricted funding from Allergan, Roche, Santen; consultancy with Centervue—all outside the remit of the submitted work.
Patient consent for publication Not required.
Ethics approval All patient data were anonymised and transferred to a single secure database. No other clinical data were made available apart from each patient's age. Subsequent analyses of the data were approved by a research ethics committee of City, University of London and this study adhered to the tenets of the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
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