Impact of RE or reduced accommodation on PrVEPs & PERGs (V1)
Research type
Research Study
Full title
The clinical impact of reduced visual acuity due to refractive error or reduced accommodation on the measured parameters in the pattern-reversal visual evoked potentials (PrVEPs) and pattern electroretinograms (PERGs).
IRAS ID
311247
Contact name
James Wolffsohn
Contact email
Sponsor organisation
Aston University
Duration of Study in the UK
0 years, 6 months, 30 days
Research summary
Research Summary
Visual electrodiagnostic tests examine the function of the back of the eye and the visual pathway to the brain to check for any dysfunctions that may affect vision. Some Electrodiagnostic tests such as pattern-reversal visual evoked potentials (PrVEPs) and pattern electroretinograms (PERGs) test vision by presenting patterns on a screen. Recommended standards emphasise the need of clear vision throughout these tests to ensure these patterns are seen clearly and signals reach the correct eye area. Therefore if individuals routinely wear glasses/contact lenses then these should be worn.
Although glasses may be required by all ages, as individuals become older, the eye loses the ability to focus on near images/words, for which further glasses are needed. Scientific literature emphasises that this also requires consideration for these tests.
Scientific literature has looked at the effects of incorrect glasses/unclear vision on PrVEPs and PERGs, but they have only considered large errors from clear vision. Realistically in clinic, smaller errors are more likely. Also limited information is available about the impact of aging eyes on these tests.
This study will therefore look at the effects of smaller errors and effect of the loss of near focus in aging eyes.
Healthy volunteers with no underlying eye problems will be recruited, of two different age groups; group 1: 18-40 years, group 2: 50 years and older. The age groups will incorporate individuals who are able to focus naturally on near images/words (group 1) and those who have lost this ability, (group 2, it has been proven in research studies that individuals over 50 years lose this ability). This will assist with improving test protocols, reporting and overall patient management.
Participants will attend once for a duration of approximately 1.5 to 2 hours. PrVEPs and PERGs will be recorded whilst glasses prescriptions/vision is altered with different lenses to determine the effects.
Summary of Results
Visual electrodiagnostic tests examine the function of the back of the eye and the visual pathway to the brain to check for any dysfunctions that may affect vision. Some Electrodiagnostic tests such as the pattern-reversal visual evoked potentials (PrVEPs) and pattern electroretinograms (PERGs) test vision by presenting patterns on a screen. Recommended standards emphasis the need of clear vision throughout these tests to ensure these patterns are seen clearly and signals reach the correct area of the eye. Therefore, if individuals routinely wear glasses/contact lenses then these should be worn.
Although glasses may be required by all ages, as individuals become older, the eye loses the ability to focus on near images/words, for which further glasses are needed. Scientific literature emphasises that this also requires consideration for these tests.
Although research has already looked at this, they have not considered more clinically realistic situations such as when patients attend appointments with old glasses, or older individuals who have reduced or lost the ability to focus on near forgot their near glasses. Additionally anyone younger than 40 years are presumed to still have the ability to focus on near objects or words, however no studies have looked at this specifically in relation to the PrVEP and PERG, hence this cannot be confirmed.
This study therefore looked at the following:
1. Understand if younger patients will benefit with glasses for near viewing distance for the PrVEP and PERG
2. To determine if older individuals who have lost the ability to focus on near would benefit with glasses for near for both the tests
3. Understand if current glasses are required to obtain accurate PrVEP and PERG results or older glasses may be ok to useResults from this study indicated that:
1. Using distance prescription only during PrVEP and PERG for younger individuals provides accurate results so they do not need additional glasses for near for these tests
2. Older individual do need to be wearing their near glasses during both the tests
3. Out of date glasses prescription impacts both the PrVEP and PERG results, where PERGs are affected more than PrVEPs.REC name
South East Scotland REC 02
REC reference
22/SS/0083
Date of REC Opinion
25 Oct 2022
REC opinion
Further Information Favourable Opinion