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Visual accommodation and sustained visual resolution in multiple sclerosis.
N A Ogden1, J E Raymond, T P Seland
1Department of Psychology, University of Calgary, Alberta, Canada.
Investigative Ophthalmology & Visual Science
|August 1, 1992
Summary
Multiple sclerosis patients struggle with sustained accommodation, leading to slower visual reaction times at varying distances. This impacts contrast sensitivity, suggesting viewing distance is key in testing.
Area of Science:
- Ophthalmology
- Neuroscience
- Vision Science
Background:
- Multiple sclerosis (MS) patients often report transient visual blurring.
- This symptom may stem from difficulties in maintaining accommodative responses at different viewing distances.
Purpose of the Study:
- To investigate if accommodative sustainment issues cause visual blurring in MS patients.
- To compare visual reaction times and contrast sensitivity between MS patients and healthy controls.
Main Methods:
- Measured accommodative range, tonus position, and pupil size.
- Assessed reaction time (RT) to optotype changes across viewing distances using a Badal lens system.
- Evaluated contrast sensitivity (CS) at a fixed viewing distance.
Main Results:
- MS patients and controls showed similar accommodative ranges and tonus positions.
- MS patients exhibited significantly slower RTs than controls when stimuli were not at their tonus position.
- Both groups had slower RTs at extreme distances, but this effect was more pronounced in MS patients.
Conclusions:
- Inability to sustain accommodation contributes to visual disturbances in MS.
- Dynamic dioptric factors influence contrast sensitivity deficits in MS.
- The relationship between accommodation tonus position and viewing distance is crucial for CS testing in MS.