Contact lens care
Types of contact lenses
There are 3 types of contact lenses: hard lenses, rigid gas permeable lenses, and soft lenses. Soft lenses are the most popular. Conventional ones can be worn for one to 2 years, while disposable ones are generally worn for between 2 and 8 weeks.
Why are soft contact lenses more popular?
Soft contact lenses are generally more popular for a number of reasons.
- Many people find soft lenses more comfortable and easier to remove than hard contact lenses.
- It is often easier to switch from soft lenses to glasses, without the initial blurriness that hard contact lens wearers can experience.
- Soft lenses are less likely to become dislodged from the eye and are useful for wearing during sports.
- Soft lenses are less likely to trap dust, eyelashes or other foreign material under the lens.
The disadvantage of soft contact lenses is that their wearable life is shorter than hard lenses, and they are more easily ruined if not cared for properly. Soft contact lenses are a hydrogel-type product and prone to contamination, so it is important that they are cleaned and disinfected regularly.
Caring for soft contact lenses
Caring for contact lenses requires a combination of cleaning, disinfecting, soaking and wetting, rinsing and storing. Some products combine 2 or more of these steps. It is likely that your optometrist has prescribed a particular lens care system suited to your particular type of lenses.
Normal tears can leave protein and oil deposits on contact lenses. If these deposits are not cleaned off they harden and can cause distorted vision, as well as reducing the wearable life of the lenses.
Soft contact lenses need 2 cleaning steps:
- detergent-like or citrate cleaners to remove the oil deposits; and
- enzymatic liquid or tablet cleaners to remove the tough protein debris.
Protein build-up should be removed daily with liquid enzyme cleaner, or weekly using enzyme tablet systems. This makes them more comfortable to wear, and reduces the risk of bacterial infection and other associated problems. Most soft contact lenses require disinfection as well as cleaning after each wearing, because they are more prone to contamination than hard contact lenses.
Tips for handling contact lenses
The following are some helpful tips for handling contact lenses.
- Always wash and dry your hands well when handling contact lenses.
- If a hard lens is lost or dropped, use a vacuum cleaner with pantyhose over the inlet to catch the lens.
- If a soft lens is lost, turn out the light and shine a torch around the room — light will reflect off the lens.
- Soft lenses become very brittle when they dry out. If a lens becomes dehydrated, rehydrate it with saline before handling it. Do not use saliva to wet the lens.
- Don’t wear lenses when around noxious fumes or smoke.
- Follow the expiry dates on contact lens solutions and discard unused solution, especially if it does not have a preservative.
- Replace the lens case every 4 weeks.
- Insert lenses before applying make-up.
- Take lenses out before removing make-up.
- Cream and liquid gel eye shadows are preferable for lens wearers. Powder eye shadows may cause particles to fall into the eye and irritate it.
- Mascara with lash building fibres may also drop into the eye.
Drug-induced contact lens problems
In general, contact lenses should be removed before applying eye drops, ointments or gels into the eye, as the medications and preservatives they contain may be absorbed into the lens. The only exceptions are when using lens wetting agents or when directed by your eye care professional. You should always check with your optometrist or pharmacist to ensure that the drops are compatible with the lens.
Although uncommon, soft lenses, in particular, can change colour when exposed to chemicals in diagnostic eye drops and to drugs which are secreted into tears. For example, rifampicin (used to treat tuberculosis and to help prevent meningococcal disease) is secreted into the tears after it is swallowed, staining the tears and lenses orange.
Some medications such as diuretics, antihistamines, decongestants and anticholinergics may cause dry, red eyes. Other drugs can also cause eye irritation or change the effectiveness of the lens. For example, sedatives can reduce the blink rate, which normally helps lubrication by washing tears around the lens.
In general, you should use your normal wetting solution, or artificial tears, for lubrication. However, even artificial tears may cause some lens wearers initial discomfort if they are not ideally suited to the type of lens being worn. If you are experiencing problems with dry eyes, speak with your pharmacist who will be able to recommend a suitable lubricant. Contact an optometrist if there is any unusual or ongoing irritation, redness or pain, or if you are having problems with your eyesight.
Last Reviewed: 12 July 2001
