Ocular Pressure
Ocular Pressure
Project Leads: Prof Paul Glasziou and Dr Rafael Perera - Collaborators: University of Edinburgh
Glaucoma is a chronic progressive optic neuropathy leading to impaired vision and sometimes blindness if untreated. The underlying pathophysiology is an accelerated loss of retinal ganglion cells, compared with the normal aging process, leading to a characteristic pattern of retinal nerve fibre layer atrophy and optic nerve head changes which ultimately result in visual loss. Open angle glaucoma (OAG) is the most common form of glaucoma, affecting about 2% of the population aged over 40 in the UK. In the UK glaucoma is second to age related macular degeneration as a main cause of blindness.
The objectives are to:
- Determine the optimal monitoring criteria in individuals with ocular hypertension (tests, frequency of monitoring, and determinants of progression to OAG) by;
(i) Identifying the optimal number of measurements required to quantify IOP risk based on the variability of the measure (Short term variation = “Noise”)
(ii) Estimate the “Noise” (N) in IOP measurement (Interobserver variability + Biological variation).
(iii). Estimate the “Signal” (S) in IOP measurement (Drift from baseline level = Mean change + Long term variability)
(iv) Estimate the S/N ratio in IOP measurements given different risk levels of OAG
(v) Determine the required frequency of measurement to detect transitions between different risk levels of OAG (10, 20, 30%)
(vi) Explore the impact of different Tonometers on the IOP measurement Noise (increase/reduce Interobserver variability)
(vii) Explore the use of other relevant clinical measures of glaucoma (visual field, optic disc and RNFL) as monitoring measures (Estimate the N, S, and S/N ratio) - Provide estimates to inform models of the impact different plausible surveillance regimes for monitoring ocular hypertension have
- Identify future research needs