Visual Function in Retinal Degeneration
Research type
Research Study
Full title
A prospective observational study of visual function, using the latest assessment techniques, to assess the utility and reliability of these assessments in patients with inherited retinal degeneration.
IRAS ID
286579
Contact name
Robert E MacLaren
Contact email
Sponsor organisation
University of Oxford, CTRG Joint Research Office
ISRCTN Number
ISRCTN24016133
Duration of Study in the UK
1 years, 8 months, 1 days
Research summary
Research Summary:
The study will use the most up-to-date visual assessment techniques to assess different aspects of vision in patients with retinal degeneration. Visual function tests, such as reading letters on a letter chart, allow measurement of the level of vision. The current standard visual tests used in ophthalmology include the Snellen and LogMAR chart. These involve reading high contrast black letters on a white background. Whilst these are good for obtaining accurate spectacle prescriptions, they are insensitive to detect early diseases changes. Other tests are available which maybe more sensitive but they are yet to be formally assessed in patients with inherited retinal disease.
In addition, other assessments used, such as the Goldmann visual fields machine, are out of date and no longer in production. Visual field assessments involves measuring the size of a seen area or the eyes sensitivity to a particular light level in an area. New machines and technology are available to do this, however, like visual function assessments they are yet to be formally assessed in many inherited retinal diseases.
Different eye conditions cause different visual function problems. When assessing visual function, it is important that the most appropriate tests are used to measure the problem. An inappropriate test, includes a test that is too difficult or one that is insensitive to visual deficits. This study will enable us to apply the latest tests and assessment methods to determine their suitability and usefulness in subjects with specific inherited retinal diseases. The overall aim is to improve clinical measures and clinical trial outcome measures.
Summary of Results:
Traditional vision tests, such as letter chart tests, mainly measure central vision and often are unable to detect small vision changes that result from eye disease. In addition, some patients with specific eye diseases that affect the retina, the light-sensitive layer at the back of the eye, are unable to perform standard peripheral vision tests and get useful results. Research to develop new treatments for eye diseases affecting the retina is ongoing. For this research to be successful, vision tests must be able to detect vision changes that matter to patients in everyday life. The Visual Function in Retinal Degeneration project evaluated a range of alternative vision tests.
Project results
Low-light microperimetry (a computer-based test that measures how sensitive the central retina is to light) was found to be the most suitable test. It reliably measures vision in the treated area of the retina and is associated with quality-of-life questionnaire results, suggesting it reflects aspects of vision that are important to daily activities. Alternative letter chart tests did not show any additional benefits compared to standard letter chart testing. Scotopic microperimetry (a version of microperimetry carried out in very low light to assess night vision) was also evaluated, but many patients found the test difficult to complete. Patient feedback showed that some tests can be tiring, highlighting opportunities to improve test delivery through clearer explanations, reassurance, and regular breaks.Conclusion
Overall, the project supports microperimetry as a key outcome measure for future retinal gene therapy trials and provides recommendations to improve patient experience and research delivery.REC name
West Midlands - Black Country Research Ethics Committee
REC reference
20/WM/0283
Date of REC Opinion
3 Dec 2020
REC opinion
Further Information Favourable Opinion