Related Experiment Videos
Vertical yoked prism--patient acceptance and postural adjustment
1University of California, School of Optometry, Berkeley 94720.
Summary
Patients may accept 2 delta base down yoked prism in multifocal lenses, but 4 delta base down prism is often rejected. Adaptation and postural changes were minimal with 2 delta prism, unlike the significant changes observed with 4 delta prism.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- Vertical yoked prism is used in multifocal lenses for thinner designs or to address oculomotor deficiencies.
- Improper vertical spectacle lens placement can also induce vertical prism effects.
- Understanding patient adaptation to vertical prism is crucial for effective prescription.
Purpose of the Study:
- To investigate patient acceptance and adaptation to vertical yoked prism in spectacles.
- To evaluate postural and perceptual responses to different magnitudes of vertical prism.
Main Methods:
- Twenty-three subjects participated in the study.
- Spectacles with no vertical prism (0 delta) and bilateral vertical yoked prism (2 delta base down and 4 delta base down) were worn by subjects.
- Patient acceptance, postural adjustments, and perceptual changes were assessed.
Main Results:
- Subjects could not significantly distinguish between 0 delta and 2 delta base down prism.
- A near-unanimous rejection of 4 delta base down prism was observed.
- Significant postural changes occurred with 4 delta prism wear, but not with 2 delta prism wear.
Conclusions:
- 2 delta base down vertical yoked prism may be acceptable for most patients.
- 4 delta base down vertical yoked prism is likely to be rejected by patients.
- Clinical application of vertical yoked prism should consider patient tolerance and potential postural effects.