Contact Lens Shift Can Compromise Vision of People with Astigmatism with the Blink...( Clinical study compares rotational ...),Health

Clinical study compares rotational stability of two differently designed toric soft contact lenses over a range of every day viewing conditions

JACKSONVILLE, Fla., Dec. 5 /PRNewswire/ -- For contact lens wearers who wonder why their vision may sometimes fluctuate during the day, the answer may lie in the design of their contact lens, a new clinical study demonstrates. The findings, say researchers, may be of particular interest to the more than 11 million wearers of soft toric contact lenses for the treatment of astigmatism, a common vision condition in which surfaces of the eye, including the cornea, have an oval shape. The findings appear in the current issue of Optometry and Vision Science, the peer-reviewed journal of the American Academy of Optometry.

(Photo: http://www.newscom.com/cgi-bin/prnh/20071205/CLW016 )

According to the study, which used a novel, infrared, video-based technique to evaluate the clinical performance of two of the most frequently prescribed toric soft contact lenses in the United States, lenses utilizing an Accelerated Stabilization Design were superior when compared to lenses using a Prism Ballast Design in two of four tasks designed to mimic real-world viewing conditions involving quick, simultaneous movements of both eyes in the same direction.

"During wide angle eye movements, tasks such as scanning a newspaper for information, gazing to the extreme side for changing lanes while driving or parking/backing up, or trying to view a flag on a putting green while teeing off in golf, a rotated contact lens can greatly compromise vision, resulting in blur and a temporary loss of visual clarity," says study co-author George A. Zikos, O.D., M.S., Manhattan Vision Associates/Institute Vision Research. "The rotational position and stability of a contact lens on the eyes during movement are critical in ensuring consistent vision whi
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