Contact Lens Shift Can Compromise Vision of People with Astigmatism with the Blink...(le wearers are performing eye movement t...),Health

Contact lenses using a Prism-Ballast design rely primarily on the effect of gravity and to a small degree the squeezing force of the upper eyelid to align the lens on the eye. Although this design concept has been shown to be effective in orienting lenses while in the doctor's chair, it's prone to rotating with the eyelids' movements (i.e., during blinking) or when the forces of gravity are not aligned with the direction of the lid forces, such as when the head is tilted when watching TV from a reclining position or while playing sports that require large eye and head movement. This may cause wearers to experience contact lens instability and some blurriness or fluctuation in vision.

In contrast, much like the on-demand four-wheel drive feature now available in many cars, contact lenses using an Accelerated Stabilization Design rotate quickly to the desired position and remain stable when properly aligned. Lenses using this design concept harness the natural pressures of a blinking eye to balance the lens in place and quickly realign the lens if it rotates out of position during all eye and head movements.

About the Study

The purpose of the study was to compare objectively the rotational stability of two differently-designed toric soft contact lenses over a range of natural viewing conditions using a novel, infrared, video-based technique.

Twenty contact lens wearers (10 men, 10 women), ranging in age from 23-55, participated in this double-blind, randomized, crossover study. Following a baseline evaluation, participants were randomly fit with one of the top two selling toric lenses -- ACUVUE(R) ADVANCE(R) Brand Contact Lenses for ASTIGMATISM (Vistakon(R), Divisio
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