The US Food and Drug Administration (FDA) on April 10 cleared the first contact lens to incorporate an additive that automatically darkens the lens when exposed to bright light.

The Acuvue Oasys Contact Lenses with Transitions Light Intelligent Technology are soft contact lenses indicated for daily use to correct the vision of people with non-diseased eyes who are nearsighted or farsighted and can be used by people with certain degrees of astigmatism, an anomaly of The eye, according to FDA.

"This contact lens is the first of its kind to incorporate the same technology that is used in eyeglasses that automatically darken in the sun," said Malvina Eydelman, Director of the Division of Ophthalmic, and Ear, Nose and Throat Devices at the FDA's Center For Devices and Radiological Health. The contact photos contain a photochromic additive that adapts the amount of visible light filtered to the eye based on the amount of UV light to which they are exposed, reports Xinhua.

This results in slightly darkened lenses in bright sunlight that automatically return to a regular tint when exposed to normal or dark lighting conditions, FDA said. FDA reviewed statistical evidence including a clinical study of 24 patients that evaluated daytime and nighttime driving performance while wearing the contact lenses.

The results of the study indicating there was no evidence of concerns with either driving performance or vision while wearing the lenses. The patients should not sleep in these contact lenses, expose them to water or wear them longer than directed by an eye care professional. FDA also warns that these contacts should not be used as substitutes for UV protective eyewear.