Abstract
Background
Blink-induced lens movement causes a reduction in visual performance that is potentially greater with toric than with spherical soft contact lenses because of the combination of vertical lens movement and rotation. This study examined the effect of the two most common methods of toric lens stabilization (prism ballast and dynamic stabilization) on vision.
Method
Four toric soft contact lens wearers were the subjects (astigmatic range 1.25 to 2.25 D). Stimulus presentation (10.5 cpd sine wave grating flashed for 16 ms) occurred at specified times up to 400 ms after the blink. Contrast thresholds were determined monocularly with spectacles and the two types of contact lenses.
Results
For the grouped data, the prism ballasted lens gave better overall visual performance than the dynamic stabilization at all times after the blink. Separate analysis of subject data suggested that this general pattern was not true for all individuals.
Conclusions
Clinical evaluation of different lens designs on individual patients is required for achieving the optimum visual performance with toric soft lenses.
Blink-induced lens movement causes a reduction in visual performance that is potentially greater with toric than with spherical soft contact lenses because of the combination of vertical lens movement and rotation. This study examined the effect of the two most common methods of toric lens stabilization (prism ballast and dynamic stabilization) on vision.
Method
Four toric soft contact lens wearers were the subjects (astigmatic range 1.25 to 2.25 D). Stimulus presentation (10.5 cpd sine wave grating flashed for 16 ms) occurred at specified times up to 400 ms after the blink. Contrast thresholds were determined monocularly with spectacles and the two types of contact lenses.
Results
For the grouped data, the prism ballasted lens gave better overall visual performance than the dynamic stabilization at all times after the blink. Separate analysis of subject data suggested that this general pattern was not true for all individuals.
Conclusions
Clinical evaluation of different lens designs on individual patients is required for achieving the optimum visual performance with toric soft lenses.
| Original language | English |
|---|---|
| Pages (from-to) | 545-549 |
| Number of pages | 5 |
| Journal | Optometry and Vision Science |
| Volume | 71 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sept 1994 |
Keywords
- Blink-induced lens movements
- Contrast sensitivity
- Dynamic stabilization
- Prism ballast
- Toric contact lenses
ASJC Scopus subject areas
- Ophthalmology
- Optometry