Contact lenses are a great option for active people, athletes, and those who prefer the freedom from eyeglasses.

The best way to get contact lenses with the best material, fitting design, and care regime that will work best for your eyes and lifestyle is to talk to your doctor of optometry.

Contact lenses are generally described by their wearing period, replacement schedule, correction style or tint.

By wearing period

Daily wear: you can only wear these lenses during waking hours, usually up to a maximum of 18 hours. Daily wear lenses are removed at night and cleaned and disinfected after each removal.

Extended wear: Extended wear lenses may be worn on an overnight basis for up to seven consecutive days (six nights). You should wear your lenses on an extended wear basis only on the advice of your doctor of optometry. Extended wear lenses generally have a higher water content or thinner center thickness than other lenses. This means more oxygen can reach the eye. However, their use has been linked to a higher incidence of eye problems. Extended wear lenses need to be cleaned and disinfected at recommended intervals and discarded after the use period.

By replacement period

It is important to replace lenses often. Soon after you put them in, contact lenses begin attracting deposits of proteins and lipids. These deposits build up and, even with ongoing lens care, start to reduce how well your contact lenses work. This can be a risk to your eye health.

Contact lenses are often prescribed with a specific replacement suited to your needs and the design of the contact lenses. 

Planned (or frequent) replacement contacts are disposed of and replaced with a new pair according to a planned schedule, usually daily, biweekly or monthly.

Planned replacement lenses generally have a higher water content or thinner center thickness than other lenses and allow more oxygen to reach the eye. They are less protein and lipid resistant, and need to be replaced more often as they become dirty more easily.

Except for daily disposables, planned replacement lenses require cleaning and disinfection after each period of wear unless they are discarded immediately upon removal. Planned replacement lenses can be worn as daily wear removed before sleep or as extended wear, if recommended by your practitioner.

A specific replacement schedule helps prevent problems before they might happen. Contact lens wearers, in turn, enjoy the added comfort, convenience and health benefits of a planned replacement program.

Unplanned replacement lenses (often called conventional lenses) are not replaced according to a predetermined schedule. They are typically used for as long as they remain undamaged, but should be replaced every 12 months. These lenses are used much less frequently and are usually reserved for special circumstances.

By type of vision correction required

Contact lenses may be identified by the type of refractive error they are designed to correct.

• Spherical contact lenses for nearsightedness (myopia) and farsightedness (hyperopia);
• Toric contact lenses for astigmatism; and
• Multifocal lenses for presbyopia, the loss of ability to focus on reading or close-up activities.

As an alternative to special bifocal contact lenses, many practitioners use a system called monovision where the dominant eye is fitted with a distance lens and the non-dominant eye with a reading lens. Approximately two-thirds of patients adapt to this type of contact lens wear.

By type of tint or colour

Contact lenses may either be clear or tinted. Tints are used to make lenses more visible
during handling, or for therapeutic or cosmetic reasons. Tints can also enhance eye colour,
or change the eye colour altogether. Three categories of tinted contact lenses are available:

• Cosmetic enhancement tints are translucent and are designed to enhance your
  natural eye colour. They are best for light-coloured eyes (blues, greens, light hazel
  or grays). When wearing these tints, the colour of your eye becomes a blend of the
  lens tint and your natural eye colour and iris pattern.
• Opaque or cosmetic tints change the apparent colour of your eyes whether they are
  dark or light. The pattern on the lens, which is coloured, overlies the coloured part of
  your eye, resulting in an eye colour with a natural look.

Visibility or handling tints are very pale, coloured just enough to make the contact lens visible while you are handling it. They usually have no effect on eye colour and are often a pale blue or green.