Contact lenses are grouped in many different ways

FOR IMMEDIATE RELEASE
(Free-Press-Release.com) November 15, 2011 -- Contact lenses are grouped in many different ways.

Cosmetic contact lenses

A cosmetic contact lens is created to change the look of the eye. These lenses may also correct the vision, but some blurring or obstruction of vision might happen due to the colour or design. In the USA, the Food and Drug Administration often calls non-corrective cosmetic contact lenses decorative contact lenses. These types of lenses seem to cause mild irritation on insertion, but after adapting to the lenses, the eyes tolerate the lenses quite well. As with any contact lens, cosmetic lenses carry risks of mild and serious complications, including ocular redness, irritation, and infection. Everyone who decides to wear cosmetic lenses should check with an eye care professionalbefore using them, as well as having frequent visits to avoid potentially blinding complications.

Scleral lenses cover the white part of the eye (i.e. sclera) and are used in many theatrical lenses. Due to their size, these lenses are difficult to insert and do not move very well within the eye. They may also hamper the vision as the lens has a small area for the user to see through. As a result they generally cannot be worn for more than three hours as they can cause temporary vision problems.

Theatrical contact lenses are a type of cosmetic contact lens that are usually used in the entertainment industry to make people’s eyes look confusing and arousing in appearance,most often in horror film and zombie movies, where lenses can make someone’s eyes look cat-like or demonic, cloudy and lifeless, or even to make the pupils of the wearer appear dilated toimmitate the natural look of the pupils under the influence of several illicit drugs.

Similar lenses have more direct medical applications. For example, some lenses can give the iris an enlarged appearance, or mask defects such as lack of (aniridia) or damage to (dyscoria) the iris.

A new popular lens in Japan, South Korea and China arethe circle contact lenses. Circle lenses look bigger because they are not only tinted in areas that cover the iris of the eye, but tinted mainly in the extra-wide outer ring of the lens. The result is the appearance of a bigger, wider iris.

Although many brands of contact lenses are lightly tinted to make them easier to handle, cosmetic lenses worn to change the colour of the eye are far less common, accounting for only 3% of contact lens fits in 2004.

As a specialist's tool, in the hands of the untrained general public, non-prescription cosmetic contact lenses might cause a health risk.

Corrective contact lenses

Corrective contact lenses are designed to improve vision. For a lot of people, there is a mismatch between the refractive power of the eye and the length of the eye, which can turn into a refraction error. A contact lens neutralises this mismatch and allows for correct focusing of light onto the retina. Conditions that are correctable with contact lenses include presbyopia,myopia (near or short sightedness), hypermetropia (far or long sightedness) and astigmatism. Contact wearers must usually take their contact lenses out every night or every few days, depending on the brand and style of the contact. Recently, there has been a new found interest in orthokeratology, which is the correction of myopia by purposely flattening the cornea which leaves the eye without contact lenses or glasses correction during the day.

ChromaGen lenses have been used and these have been shown to have some limitations with vision at night although otherwise producing large improvements in colour vision.An earlier study showed very significant improvements in colour vision and patient satisfaction.

For people with certain colour deficiencies, a red-tinted "X-Chrom" contact lenses may be used. Even though the lens does not restore normal colour vision, it allows some colour-blindindividuals to distinguish colours better.

Later work that used these ChromaGen lenses for dyslexics in a random, double-blind, placebo controlled trial showed large improvements in reading ability over reading without the lenses. This system has been approved by the FDA in the United States.

For more detail visit :- http://www.manlyoptometrist.com.au

eye correction     ortho-k     orthokeratology