CONTACT LENS TYPES AND MATERIALS:
Soft Contact Lenses: Soft contact lenses are made of soft, flexible plastics that allow oxygen to pass through to the cornea. Soft contact lenses may be easier to adjust to and are more comfortable than rigid gas permeable lenses. Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you wear your lenses.
Rigid Gas Permeable (RGP) Contact Lenses: Rigid gas permeable contact lenses (RGPs) are more durable and resistant to deposit buildup. They tend to be less expensive over the life of the lens since they last longer than soft contact lenses. They are easier to handle and less likely to tear. However, they are not as comfortable initially as soft contacts and it may take a few weeks to get used to wearing RGPs, compared to several days for soft contacts.
Orthokeratology (Ortho-K): Orthokeratology, or Ortho-K, is a lens fitting procedure that uses specially designed rigid gas permeable (RGP) contact lenses to change the curvature of the cornea to temporarily improve the eyes ability to focus on objects. This procedure is primarily used for the correction of myopia (nearsightedness). Overnight Ortho-K lenses are the most common type of Ortho-K. There are some Ortho-K lenses that are prescribed only for daytime wear. Overnight Ortho-K lenses are commonly prescribed to be worn while sleeping for at least eight hours each night. They are removed upon awakening and not worn during the day. Some people can go all day without their glasses or contact lenses. Others will find that their vision correction will wear off during the day.The vision correction effect is temporary. If Ortho-K is discontinued, the corneas will return to their original curvature and the eye to its original amount of nearsightedness. Ortho-K lenses must continue to be worn every night or on some other prescribed maintenance schedule in order to maintain the treatment effect. Your eye care professional will determine the best maintenance schedule for you.
Toric Lenses: A toric contact lens has two different powers or curvatures so that it can correct for both astigmatism and either myopia (near-sightedness) or hyperopia (far-sightedness). Increasingly, toric contact lenses, which typically combine the effects of a cylindrical lens with that of a spherical lens, are being prescribed for people who are astigmatic (i.e. have corneas that are not perfectly round) and also need help with their far-away or close-up vision. These are people who, in the past, may have been told that they are not suitable for contact lenses.
Multi-focal Lenses: Multifocal contact lenses are used to correct both short sight as well as long sight. Bifocal have a small portion of the lens at the bottom for correcting short sight and the top portion is used to correct long sight. Multifocal soft contact lenses are difficult to make. Multifocal contact lenses are the best choice for correcting vision, especially during old age. The condition that usually occurs is known as presbyopia, the hardening of natural eye lens or the retina.
Coloured Lenses: Coloured Contact Lenses or Cosmetic Contact lense are designed to change the appearance of the eye. These lenses may also correct the vision, but some blurring or obstruction of vision may occur as a result of the color or design.
CONTACT LENS TYPE BY FREQUENCY:
Daily Disposable Lenses: Daily disposable contact lenses are designed to be worn for a single day, and then thrown-away. As such, these lenses represent the ultimate in convenience for the contact lens wearer. No need for extensive cleaning procedures - you don't even need a contact lens case unless you want to take the lenses out for a while. Moreover, daily-disposable contacts are generally considered the safest and healthiest type of contact lenses because the use of a fresh pair of lenses every day minimizes the chance for build-up of harmful pathogens on the lens surface.
Monthly Disposable Lenses: Contact lenses are worn by more than 75 million people around the world and a growing number of these are choosing to wear monthly disposable lenses. These contacts can be worn for up to one month, as directed by your optometrist. This means that at the end of every day you remove your lenses and clean them before reinserting them. Read our caring for contact lenses article on our blog for more information about cleaning and looking after your lenses.
Bi-Weekly Disposable Lenses: Bi-Weekly Acuvue contact lenses are soft lenses which can be worn every day for two weeks. At the end of this period they are thrown away.