This study was led by Dr Jennifer Burr in HSRU in collaboration with Birmingham, Oxford, London, Rotterdam, Dunfermline and Nottingham and funded by the National Institute for Health Research, Health Technology Assessment Programme (Project: 07/46/02).
The aim of the study was to determine the optimum frequency of monitoring patients identified as at risk of glaucoma due to raised intraocular pressure (IOP), a condition called ocular hypertension, and the extent this varied according to individual risk characteristics.
We used a discrete event simulation economic modelling evaluation to compare alternative monitoring pathways. Systematic reviews and individual patient data analysis were conducted and public preferences elicited in order to provide data to structure and populate the economic model. These included reviews of available risk prediction models and also of the agreement between tonometers. We used existing datasets to validate identified risk models and determine optimal monitoring criteria for measuring IOP and for tests to detect glaucoma. Public preferences for a monitoring scheme were elicited using a discrete choice experiment of the general population.
The study found the best available risk prediction model was the OHTS-EGPS means model. Study findings support the clinical importance of establishing a true baseline IOP prior to initiating monitoring or treatment and the same type of tonometer should be used to compare IOP measurements in an individual. Based on a small sample, findings suggest biennial IOP monitoring for untreated or stable treated OHT but the optimal frequency of clinical testing (perimetry or optic nerve evaluation) to detect glaucoma remains uncertain.
The economic evaluation findings suggested no clear benefit in intensive monitoring to detect glaucoma. It was clear from public preference data that any service reconfigurations should consider patient experiences, ensuring adequate time to explain the purpose of monitoring and avoid treatment side effects. If the NHS costs for repeat visits to monitor IOP response to treatment are minimised, biennial hospital-based monitoring appears optimal. The economic model may not have fully captured all data uncertainties. The feasibility of community care pathways should be explored. Further research is recommended to refine the glaucoma risk prediction model in a UK setting and determine the optimum type and frequency of serial glaucoma tests.
Katie Banister; email@example.com
Hernández R, Burr JM, Vale L, Azuara-Blanco A, Cook JA, Banister K, Tuulonen A, Ryan M & Surveillance of Ocular Hypertension Study group 2016, 'Monitoring ocular hypertension, how much and how often? A cost-effectiveness perspective' Br J Ophthalmol, vol Online First., 10.1136/bjophthalmol-2015-306757
Takwoingi Y, Botello AP, Burr JM, Azuara-Blanco A, Garway-Heath DF, Lemij HG, Sanders R, King AJ, Deeks JJ; for the Surveillance for Ocular Hypertension Study Group. External validation of the OHTS-EGPS model for predicting the 5-year risk of open-angle glaucoma in ocular hypertensives. Br J Ophthalmol 2013 Dec 19. doi: 10.1136/bjophthalmol-2013-303622. [Epub ahead of print]
Burr JM, Botello AP, Takwongi Y, Hernandez R, Vazquez-Montes M, Elders A, Asoaka R, Banister K, van der Schoot J, Fraser C, King A, Lemij H, Sanders R, Vernon S, Tuulonen A, Kotecha A, Glasziou P, Garway-Heath D, Crabb D, Vale L, Azuara-Blanco A, Perera R, Ryan M, Deeks J, Cook J. Surveillance for ocular hypertension: an evidence synthesis and economic evaluation. Health Technol Assess 2012;16:29.
Cook JA, Botello AP, Elders A, Alia A, Azuara-Blanco A, Fraser C, McCormack K, Burr J, Surveillance of Ocular Hypertension Study Group. Systematic review of the agreement of tonometers with Goldmann applanation tonometry. Ophthalmology 2012;119(8):1552-1557.
Hernández R, Vale L, Ryan M, Burr JM for the Surveillance of Ocular Hypertension Project group. Incorporating results from a discrete choice experiment into a discrete event simulation model: the case of monitoring individuals with ocular hypertension. Health Technology Assessment International (HTAi), Rio de Janeiro, Brazil, June 2011
Botello AP, Elders A, Ali A, Cook J, McCormack K, Azuara-Blanco A, Burr JM for the SOH study group. A systematic review of agreement between measurement tools: alternative tonometers for monitoring ocular hypertension. Health Technology Assessment International (HTAi), Dublin, Ireland, June 2010