A: Depending on the make of the lenses, some last for one day, some for two weeks and some for one month.

A: Sleeping in your contact lenses puts you at greater risk of eye infections and corneal ulcers, but depending on the type of lenses you are wearing, occasional overnight wear is acceptable. However, sleeping in them regularly is not healthy.

A: Usually, most people can, depending on your prescription, your visual requirements and your lifestyle.

To wear contact lenses successfully requires a partnership between you and your optometrist. His or her knowledge, skill and care must be combined with a continual effort on your part. Regular cleaning and disinfecting are essential to ensure clean, hygienic and comfortable lenses.

Regular optometric check-ups are necessary to ensure long-term success, and if contact lens wear is being considered, the on-going costs involved must be borne in mind. In conclusion Your optometrist is a skilled and caring professional. Together you will make an intelligent decision on contact lens wear after considering all the available options. Have your eyes examined at least once a year.

To find the right contact lenses for your circumstances, you have to consider your needs and wants.

Your visual needs
Your eyes, vision problems, lens prescription and eye health may limit your lens choice. Your optometrist will advise you on these matters after a series of tests to determine your eye health, vision history and contact lens evaluation.

Your lifestyle
Your choice of lenses must be compatible with your daily activities. For sportsmen and sportswomen, soft lenses are ideal. If the sharpest vision is needed for your job, then RGP lenses could be advised. And if you enjoy outdoor life or travel frequently, these activities would need to be considered.

Your personality

Broadly speaking, contact lenses fall into three categories:

Soft lenses
These are made from a very soft and flexible water-absorbing plastic that allows oxygen to pass through to nourish the eye. Adaptation is usually very easy and these lenses are comfortable to wear almost from the start. They have a close fit, which makes them more difficult to dislodge and under which dirt is less likely to get trapped. The vision offered is good, but the focus is a “soft” type. They need periodic replacement.

Rigid gas-permeable (RGP) lenses
Made of a different rigid or slightly flexible plastic that allows oxygen and water to pass through. They cover only part of the cornea. A longer adaptation period and consistent wear are required to maintain adaptation. They offer sharp, crisp vision, correction for most vision problems and durability, and require less frequent replacement than soft lenses.

Disposable lenses
Made of soft, flexible materials called hydrophilic polymers, which are able to absorb water that carries oxygen to the eye. They are easy to adapt to and because of the higher water content are extremely comfortable. Cleaning and disinfection procedures are recommended according to the type of lenses you wear. There are three different types of disposable contact lenses from which to choose. Your choice should be governed by your particular requirements:

Extended wear of disposable lenses should only be done under controlled conditions and with the guidance of your optometrist. The “throwaway” factor means there is less chance of deposit accumulation which could impair the health of the eye.

Tinted lenses
These have a number of applications, mostly of a cosmetic nature (changing the eye colour, for example). They may also correct refractive errors.

Contact lenses for astigmatism
Soft, rigid and disposable lenses are available for the correction of astigmatism.

Contact lenses may give better vision than spectacles for some visual conditions such as severe short-sightedness, astigmatism, long-sightedness, corneal distortion or after cataract removal. A wider field of view is afforded by contact lenses, as the side view is not blocked as with spectacles frames. Contact lenses are unaffected by rain and do not “fog up” with changes in temperature and perspiration. Some people think they look unattractive in spectacles, while sportsmen often find contact lenses far more convenient.