Effect of Correcting Astigmatism 20deg Off-axis
Research type
Research Study
Full title
Effect of Correcting Astigmatism 20 degrees Off-axis on Multifocal Visual Performance and Acceptance
IRAS ID
300445
Contact name
Ruchi Gupta
Contact email
Sponsor organisation
CooperVision International Limited
Duration of Study in the UK
0 years, 6 months, 25 days
Research summary
Standard of practice is to correct presbyopes (people over 40 years needing both distance and near corrections) who are short sighted (myopia) or long sighted (hyperopia) and have astigmatism with progressive contact lenses that do not correct low level of astigmatism. This is possible because the vision produced is adequate in terms of quality of vision and visual acuity. Previous studies have quantified the potential benefits of also correcting low levels of astigmatism and have shown that they produce better visual acuity. However, the approach would require an extremely large number of different contact lens powers, which is not practically manageable. In contact lenses the astigmatism is corrected, but the direction of the correction is not perfect but within 20 degrees the number of contact lenses required is manageable. The question, is therefore, whether this approach still achieves an improvement in visual acuity and visual performance.
The rationale for the study is to mimic the situation where the astigmatic correction is 20 degrees off optimal direction by using contact lenses and over spectacles to measure in the clinic the visual acuity without astigmatic correction (control current practice) and with astigmatic correction 20 degrees off axis(test).REC name
London - Westminster Research Ethics Committee
REC reference
21/PR/0749
Date of REC Opinion
3 Jun 2021
REC opinion
Further Information Favourable Opinion