Contact lenses - information

Buying Contact Lenses by Internet, Phone or Mail - Advice from the U.S. Food and Drug Administration on making such purchases safe and effective.

Color Contact Lenses - Informational site on popular colored contact lenses. Includes a lens price guide on all major brand name colored contact lenses.

Consumer Guide to Contact Lenses - AllAboutVision.com - Learn about types of contact lenses and who can wear them, caring for contact lenses, and advice on where to buy.

Contact Lens Consultants - Information and descriptions about all types of contacts.

Contact Lens Council - Advancing quality eye care to the public by providing information on the safe use of contact lenses.

Contact Lens Manufacturers Association - Guide to lenses, individual vision needs, consumer and medical opinions, and resources.

The Contact Lens Society of America - The CLSA is an educational organization. CLSA's objective is to educate and share knowledge among fitters of contact lenses.

Focus Night & Day Contact Lenses - New generation of silicone hydrogel soft contact lenses approved by the FDA for up to 30 days of continuous wear.

Top 10 Reasons to Get Contact Lenses - Explains advantages of contact lenses over glasses or surgery; also includes contact lens myths, and do's and don'ts.

Contact lenses - stores

AC Lens - Contacts, accessories, and free email consultation with a licensed optometrist.

Advantage Contacts - Contact lens retailer carrying all major brands.

Affordable Lenses - Replacement soft contacts by eyecare professionals. Includes a "Doctor On Call" feature.

All American Contact Lenses - Offering name brand contact lenses and delivery at an affordable price since 1998.

Bennewitz - German based retailer of contact lenses, sunglasses, reading glasses and other optical equipment. Ships worldwide and includes shopping cart with currency converter.

Best Price Contacts - Offers a selection of name brand disposable lenses at discount prices.

Big Brown Eyes - Assortment of colored, non-perscription lenses. UK site delivers worldwide.

CLE Contact Lenses - Retailer of replacement lenses. Worldwide shipping of all major brands.

Clear Vision Contact Lenses - Online retailer of replacement soft contacts.

CoastalContacts.com - Retailer features colored, disposable and bifocal contact lenses at discount prices.

Contact Lens Center - Retailer of replacement contacts, designer frames, and sunglasses.

Contact Lens Connection - Retailer of replacement soft and rigid gas permeable (RGP) contacts.

The Contact Lens Shop - Offers brand name contact lenses and solutions. UK based and delivers only inside Europe.

Contact Lens Store - Offers prescription and non-prescription contact lens replacements from major manufacturers.

2020 Contact Lenses - Offers brand name replacement contact lenses.

Contact Lenses by Colored Contacts. - Offering major brand contact lenses to change eye color using cosmetic colored contacts.

Contact Us Today - Optometrist offering online sales of contacts.

ContactlensesUK.net - UK supplier of brand name contact lenses.

ContactLensEtc.com - Includes American Hydron, Bausch and Lomb, Biocompatibles Ciba Vision and Cooper Vision.

Contactlensshop - Australian based retailer, offering brand name disposable and rigid gas permeable replacement contacts. Worldwide delivery and secure online order form.

ContactMania.com - Supplier of replacement contact lenses. Includes contact lens tips and FAQs.

1-800-Contacts - Retailer of replacement contact lenses from all major manufacturers.

ContactsLand.com - Offers discounted, brand name replacement contact lenses.

Contacts4Less.com - Supplier offering monthly, weekly, colored, or toric lenses at a low cost.

E-World Contacts - Brands include Acuvue, Wild Eyes, Bausch and Lomb, and Crazy Eyes.

Eye Clinic - UK supplier of contact lenses and solutions.

Eye Excel - Offers brand name contact lenses and accessories.

Eye Mate - Direct retailer of brand name contacts.

Eye on Fashion - Offering brand name prescription and non-prescription contact lenses.

Eyes International - Sells disposable, colored, bifocal, and toric contact lenses.

Family Vision Center - Connecticut based optometrist offering online sales of replacement contacts lense.

1-800-Get-Lens - Supplier offering monthly, weekly, colored, or toric contact lenses.

Lens and Eyes - Supplier of brand name contact lenses.

Lens.com - Retailer of brand name contact lenses.

LensDiscounters - Canada based retailer offering a variety of brand names. Shipping offered to US and Canada.

Lenses by Mail - Offers contact lenses, sun and reading glasses. Catalogue with prescription data entry form and shopping cart, FAQs and order tracking. Ships world wide and includes currency converter.

Lenses For Less - Discount retailer of replacement contact lenses. A service of Oakwood Eye Clinic in Dayton, OH.

Lensestogo.com - Includes disposables, toric, and colored. Located in Ireland, site delivers internationally.

Lensite.com - A variety of gas permeable and soft lenses. UK site delivers internationally.

LensLand - Shop for brand name contacts by the leading manufacturers.

LensPalace.com - Offers brand name lenses and eye care products.

LensQuest - Supplier of discounted brand name contacts, and special effects lenses for medical, theatrical and entertainment purposes.

LensSolutions.com - Retail sales of lens solutions.

Lensway - Contact lens retailer selling all major brands. U.K. based

LensWorld - Discount retailer of replacement soft lenses.

Nationwide Lens - Offers replacement contacts from all major manufacturers.

New Contacts - Offers a range of brand name contact lenses.

New County Optical - Discount retailer of contact lenses with five full-service optical stores in New York state.

Optical Worldwide - Supplier of brand name disposable contacts.

Payless Contacts - Online retailer of all major contact lens brands.

Postcontact.com - UK supplier of brand name contact lenses and sunglasses.

RGP Lens Company - Replacement for rigid gas permeable (RGP) and hard (PMMA) contact lenses.

1SaveOnLens - Offers replacement contact lenses from major brands as prescribed by eye-care professionals.

Sightcare2000 - Offers brand name contact lenses, solutions, binoculars and magnifying glasses.

SmartView Contacts - Offers replacements from many manufacturers. Lenses can be selected by maker or type. Ships worldwide.

1stPlaceContactLenses.com - Replacement retailer of all major brands of soft contacts.

TryColorContacts - Retailer of disposable color contact lenses, sold by the pair.

Vision Contact Lenses - Offers discounts on major brand name contact lenses.

VisionDirect.com - Offers brand name disposable, color and special effects contacts.

Novelty and Color contact lenses

Contour Contact Lens Ltd - Custom designed special effect and cosmetic contact lenses. Caters to the film industry and corneal trauma patients.

Evil Eyes - Sells novelty contact lenses. Also retailer of gothic goods.

EyeColor.com - Color and special effect contact lenses for fashion and fun.

Fx Eyes - Special effect contact lens designs.

9mm Special Effects - Source for theatrical contact lenses.

Phunky Eyes - UK based retailer of coloured and theatrical contact lenses.

Professional Vision Care - Offers special effects contact lenses for the entertainment industry.

Wild Eyes - Contacts for the terminally gothic, hypnotica, alien, bloodshot, or Manson's white out.

Contact lens article

A contact lens (also known as a "contact") is a corrective, cosmetic, or sometimes protective lens placed on the cornea of the eye.

History

The idea of applying a corrective lens directly to the surface of the eye was first proposed as early as 1508, by Leonardo da Vinci and similar concepts surfaced from René Descartes in 1636, but it was not until 1887 that the German physiologist Adolf Eugen Fick constructed the first successful contact lens.

Usage

It has been estimated that between 32 and 35 million Americans wear contact lenses.

Types of contact lenses

Contact lenses are available in a number of varieties.

Corrective vs. cosmetic contact lenses

A corrective contact lens is a contact lens designed to improve vision. A cosmetic contact lens is a contact lens designed to change the appearance of the eye.

Contact lenses typically correct vision by refracting or bending light to focus on the eye's retina. The specific dioptre that is required to treat the patient's condition can be found with the help of an optometrist and provided by an oculist. The thickness and shape of the contact lens will also vary with the increase in dioptres, and according to the condition that is being treated: Near (or short) sightedness (myopia), far (or long) sightedness (hypermetropia), or astigmatism.

Some contact lenses correct nearsightedness by flattening the cornea.

Heavily tinted contacts are tinted to change the color of the iris, and are used for cosmetic reasons. Some standard contact lenses are slightly tinted in order to make them more visible for handling purposes.

Some companies produce contacts that can change the tint or color appearance of the eye, or can place various designs on it (opaque lenses). There also exist contacts that can give the iris an enlarged appearance, or can be used to mask congenital defects (iris coloboma), absence (aniridia) or damage (dyscoria) to the iris. These contacts are rarely seen day-to-day, although many performers, both in music and movies, commonly use them for artistic purposes. These types of contacts can also have all the features common of corrective contacts, although some blurring or obstruction of vision may occur based on the specific contact lens design being used. Some contacts cover the whites (or sclera) of the eye; these are referred to as scleral lenses.

Some notable musicians that have been known to use such contacts are Wes Borland, Marilyn Manson, and Twiztid.

These lenses were also featured in Star Wars Episode I: The Phantom Menace worn by Ray Park, who played Darth Maul.

Soft vs. hard contact lenses

Contact lenses may also be classified as either soft or hard. Hard contacts are typically not disposable, while soft contacts often are. Some soft contacts are also known as extended wear lenses. The most commonly used contact lenses today are of the soft variety, invented in 1961 by the Czech chemist Otto Wichterle (1913–1998).

Contact lenses (both soft and hard) are made of various types of polymers, the latest containing some variant of silicone hydrogel. Previously, hard contact lenses were made of a polymer known as PMMA. They have since been replaced by rigid gas-permeable (RGP) contact lenses. Many contact lenses are made of hydrophilic (water-absorbing) materials, thereby allowing oxygen to reach the cornea, and make the lens more comfortable to wear.

Piggybacking contact lenses refers to the wearing of a smaller, rigid lens atop a larger, soft lens. This is done for a variety of clinical reasons where a single lens will not provide the optical power, fitting characteristics or comfort required.

Rigid contact lenses are also used to help correct vision in patients with corneal conditions, such as keratoconus, where soft contact lenses or glasses prove ineffective. Rigid contact lenses trap tears beneath the lens. Since the refractive index of tears is very close to that of the cornea, The tears pass light through the affected cornea with minimal distortion. The result is a lens that acts as a regularly shaped "artificial cornea," and improved vision.

Daily vs. extended wear contact lenses

A daily wear contact lens is a contact lens designed to be removed prior to sleeping. An extended wear contact lens is a contact lens designed for continuous overnight wear, typically for 6 or more consecutive nights. Newer materials, such as silicone hydrogels, allow for even longer wear periods up to 30 consecutive nights; these longer-wear lenses are often referred to as continuous wear (CW). Generally, EW lenses are discarded after the specified length of time. These are increasing in popularity owing to their obvious convenience. Such contact lenses are able to be worn for this extended period because of their high oxygen permeability (typically 5-6 times greater than conventional soft lenses), which allows the eye to remain remarkably healthy.

Extended lens wearers generally have an increased risk for corneal infections and corneal ulcers primarily due to tear film instability and bacterial stagnation.

Spherical vs. toric contact lenses

A spherical contact lens is a contact lens in which all meridians of the lens have the same power correction. A toric contact lens is a contact lenses in which the power correction in one meridian of the lens differs from the power correction in the other meridians. People with astigmatism, both myopic (nearsighted) and hypermetropic (farsighted), who have been told they are not suitable for regular contact lenses may be able to use Toric lenses. Toric lenses are made from the same materials as regular contact lenses but have a couple of extra characteristics:

* They have two powers in them, one for spherical correction and the other for the 'cylinder'.
* They are designed to keep the lens in a stable position regardless of eye movement. Typically, the lens is weighted more at the bottom and is marked by tiny striations so the wearer can insert them in the correct position, or they are designed in such a way that blinking will reset the lens to the correct orientation.

Cleaning and disinfection products

While daily disposable lenses require no cleaning, other types require regular cleaning and disinfecting in order to retain clear vision and prevent infections. There are a number of products that can be used to perform these important tasks:

* Multipurpose solution - The most popular cleaning solution for contact lenses. Used for rinsing, disinfecting, cleaning and storing the lenses. Instead of using many different products this is the best and easiest way to clean contacts.
* Saline solution - used for rinsing the lens after cleaning and preparing it for insertion.
* Daily cleaner - used to clean lenses on a daily basis. Usually one puts a few drops of cleaner on the lens and rubs for about 20 seconds (check directions) on each side. One must be extra careful in this step if one has long fingernails.
* Hydrogen peroxide solution - used for disinfecting the lenses. Available as 'two-step' or 'one-step' systems. If using a 'two-step' product, one must ensure that they neutralise any lens taken out of hydrogen peroxide with 'Step 2' before wearing the lens otherwise it can be an extremely painful experience! (do NOT use saline to rinse away the peroxide). Some such solutions, such as CIBA Vision's Clear Care, come with a special storage case that contains a catalyzing disk. If soaked in the solution with the disk for at least six hours, the hydrogen peroxide decomposes and the remaining solution is a simple saline solution that will not harm the eye. This type of cleaning solution is used commonly by people with extremely sensitive eyes that are irritated easily by standard solutions.
* Enzymatic cleaner - used for cleaning the protein off of lenses, usually on a weekly basis. Typically, this cleaner is in tablet form. Using only the daily cleaner may not be sufficient to prevent protein deposits which may make contact lenses uncomfortable or lead to various eye problems.

Some products may contain preservatives such as thimerosal. However, about 10% of contact lens wearers have problems with these products, a reason why several brands no longer use it. Such thimerosal-free products are sometimes labelled "for sensitive eyes". Products that do not contain any preservatives usually have shorter expiration dates. For example, non-aerosol preservative-free saline solution typically only last two weeks once opened.

Attribition: This informational article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Contact lenses.