Multi-dimensional Stimuli for Clinical Perimetry
Research type
Research Study
Full title
Functional Mapping of the Biological Changes in the Retina in Glaucoma
IRAS ID
152375
Contact name
Tony Redmond
Contact email
Sponsor organisation
Cardiff University
Duration of Study in the UK
3 years, 0 months, 0 days
Research summary
'Standard Automated Perimetry' (SAP) is the gold standard clinical test of the visual field. During the test, the patient must press a button to indicate that they have seen a small spot (presented on a screen) in their peripheral vision. The brightness of the spot is increased and decreased according to their responses, and the instrument attempts to find the dimmest spot that is still perceivable at many locations in the visual field.
This technique is characterised by several important shortcomings that limit its usefulness for measuring progressive deterioration in glaucoma:
• The variability of the test increases in damaged areas of the visual field.
• In patients with moderate disease, many visual field locations have sensitivities that are well beyond the measurable range.
• Moreover, the extremely high stimulus illumination levels may cause artefacts and render the test unrepresentative of the patient’s vision in real-world conditions.Furthermore, a recent study (Redmond et al IOVS, 2010) indicated that greater accuracy and precision of visual field testing might be achieved by varying the area of the spots, either instead of varying brightness, or simultaneously with it.
To test this hypothesis, two groups of participants (glaucoma patients and healthy controls) will be recruited. After establishing eligibility with some standard ophthalmic tests, both groups will be invited to undertake 4 types of visual field test: brightness-varied stimuli (one of standard size and one significantly smaller); area-varied stimuli; and brightness-and-area-varied stimuli.
Once the optimum of the four tests is found, we will investigate its test-retest performance, and its performance in the presence of increased light scatter (that patients with cataract generally experience), compared to the current standard test.
The study is sponsored by Cardiff University and will last 3 years in total. It is funded by a postgraduate scholarship awarded by the College of Optometrists.
REC name
East of Scotland Research Ethics Service REC 2
REC reference
15/ES/0070
Date of REC Opinion
18 May 2015
REC opinion
Further Information Favourable Opinion