contact lens iris color change - soft perm contacts

lensesesOver 140 million people in the United States wear lenseses. People whose eyes have refractive errors do not see clearly without glasses, because the light emitted from the objects they are observing does not come into focus on their retinas. For people who are farsighted, images come into focus behind the retina; for people who are nearsighted, images come into focus in front of the retina. Lenses work by changing the direction of light so that images contact come into focus on the retina. The greater the index of refraction of the lens material and the greater the difference in the curvature between the two surfaces of the lens, the greater the change in direction of light that passes through it, and the greater lens the correction.Lenses can be unifocal, with one correction for all distances, or they can be correct for more than one distance (multifocal). iris One type of multifocal, the bifocal, has an area of the lens (usually at the bottom) that corrects for nearby objects (about 14 in from the eyes); the remainder of the lens corrects for distant objects (about 20 ft from the eyes).

Over 32 million people in the United States wear these small lenses that fit on top of the cornea. They provide a field of view unobstructed by lenses frames; they do not fog-up or get splattered, so it is possible to see well while walking in the rain; and they are less noticeable color than any lenses style. On the other hand, they take time to get accustomed to; require more measurements for fitting; require many follow-up visits to the eye doctor; can change lead to complications such as infections and corneal damage; and may not contact correct astigmatism as well as lenseses, especially if the astigmatism is severe.