City Research Online

Abstract

Glaucoma describes a group of optic neuropathies characterised by progressive irreversible loss of visual function. Within this thesis, a health economic model was constructed to map service provision from diagnosis considering two competing strategies: the current practice of annual visual field (VF) monitoring against the proposed guidelines of performing 6 VFs in the first two years. The constructed model found the proposed practice to be cost effective at a willingness to pay ceiling ratio of £30,000 per quality adjusted life year (QALY), identifying an incremental cost effectiveness ratio (ICER) of £21,679. The findings of the model however were potentially sensitive to the modelled infrastructure improvement costs required to undertake the proposed guidelines and a costing study to more accurately ascertain these costs was recommended.

Following this study, statistical analysis of 473,252 VFs was undertaken to investigate trends in initial identification and progression rates whilst also narrowing their parameters within the health economic model. Consequently, the average level of glaucomatous vision loss at diagnosis was found to be improving by 0.11 dB per year on average whilst proportions of patients with ‘advanced’ loss at diagnosis fell significantly from 30% to 21%. Average progression rates were found to have fallen from -0.11 dB per year to -0.06 dB per year whilst average rates of loss in older eyes (>70 years) were found to progress faster than in younger eyes (<60 years). Furthermore, testing frequency was found not to vary by visual impairment risk factors. The constructed health economic model was subsequently updated to incorporate the more narrowly defined parameter distributions whilst also being re-specified to incorporate societal costs of visual impairment to count the true costs of the disease. This resulted in an improved ICER of £11,382.

In conclusion, it is likely that implementing the proposed guidelines of 6 VFs in the first two years is more cost-effective than annual monitoring. This argument is further reinforced once societal costs are accounted for however a scoping study to examine the required costs of improving the glaucoma monitoring infrastructure is required.

Publication Type:	Thesis (Doctoral)
Subjects:	R Medicine > RE Ophthalmology
Departments:	School of Health & Psychological Sciences > Optometry & Visual Sciences Doctoral Theses School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses

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