What are contact lenses?

Contact lenses are thin, transparent hydrogel disks that are placed directly on the surface of the eye and float over it to correct vision.

Contact lenses are thin, transparent hydrogel disks that are placed directly on the surface of the eye and float over it to correct vision. They can correct myopia and farsightedness. They can also correct astigmatism and presbyopia.

The principle for contact lenses is the same as for glasses. They bend the light and redirect it to the retina to improve your vision.

What are contact lenses made of?

Today most people wear soft contact lenses made of a moisturizing rich material called a hydrogel. Hydrogel lenses are breathable, allow oxygen to pass through them to keep your eyes healthy and fresh.

There are different types of contact lenses available to suit your vision and individual lifestyle needs. Your eye care professional can help you choose the right type of lens for you.

Types of contact lenses

• Soft Contact Lenses

  Soft contact lenses are the preferred choice among the majority of users, more than 80% of contact lens users use them for being the most comfortable and practical. They come in several versions, depending on how they are used.

• Rigid and Gas Permeable Contact Lenses

  Hard contact lenses, most commonly used today are rigid and gas permeable contact lenses (RGP). They are made from plastic and other materials such as silicone or fluoropolymers. Hard lenses retain their shape, however, allowing a free flow of oxygen between the lenses and the cornea. RGPs may be the best option when the cornea has enough astigmatism to change its shape (it has the shape of an egg instead of an orange); A soft contact lens does not provide such clear vision. They may also be preferred when a person has allergies or tends to form protein deposits in contact lenses or if he works in environments saturated with gases that could affect the cornea.

• Other Types of Contact Lenses

  • Daily Use Lenses

    Daily wear lenses are the least expensive, and are removed every night and replaced with an individualized frequency. They should not be used as long-term lenses.

  • Extended Use Lenses

    Long-wearing lenses are worn overnight, but are removed at least once a week for thorough cleaning and disinfection. These are recommended less frequently, as there is an increased risk of corneal infection with any nighttime use of contact lenses.

  • Disposable Lenses

    Disposable lenses are more expensive, but they are prosthetic. They are removed every night and replaced daily, weekly or monthly. Disposable lenses are occasionally recommended for people with allergies and those who tend to form protein deposits on lenses.

  • Cosmetic or Decorative Contact Lenses

    Cosmetic or decorative contact lenses are color lenses that change the appearance of eye color, and in the case of circular lenses they also make the iris appear larger. Decorative lenses are available by prescription and should only be used after a vision examination and be tested in the presence of a vision professional. Decorative contact lenses sold without prescription, including circular lenses, are illegal and pose a serious danger to your eye health, as they can cause eye injuries and infections, and loss of vision.

  • Soft Toric Contact Lenses

    Soft toric contact lenses can correct astigmatism, but sometimes not as well as RGP lenses do. They are usually more expensive than other contact lenses.

    The shape of the toric contact lenses creates different refractive powers, or focus, in the vertical and horizontal orientations. Refractive power increases or decreases gradually as the eye moves through the lens.

  • Bifocal or Multifocal Contact Lenses

    Bifocal or multifocal contact lenses are available in soft varieties and RPGs. They can correct myopia, farsightedness and astigmatism in combination with presbyopia. Cleaning and disinfection depend on the lens material. Often the visual quality is not as good as with simple vision lenses, however, the ability to correct presbyopia is worth for some people.