Contact lenses are becoming increasingly popular as they provide an alternative to spectacles as a vision corrective measure. Many people suffering from refractive errors choose to wear contact lenses as they provide excellent vision and comfort as well as convenience. Contact lenses can also minimize, and in many cases eliminate, the inconvenience caused by poor vision and the effect it may have on the wearer's life-style. This is particularly evident in the case of people whose lives involve regular physical activities such as athletes and others who rely on using instruments held in close range to the eyes such as photographers and camera operators. Contact lenses provide a better cosmetic effect than spectacles as they are hardly noticeable and do not leave any marks or traces of wear.

At the same time, contact lenses can have disadvantages if they are improperly prescribed or used. Contacts must be individually prescribed to ensure that each eye is fitted with a proper corrective contact lens. Poor contact lens prescribing and/or fitting can cause not only problems in the vision correction process, but also serious eye problems such as infections. Contact lenses are worn in direct contact with the eyes and must therefore be cared for, cleaned, disinfected and stored correctly. This ensures that no unwanted residue or substance is building up on the contact lenses that may otherwise be transmitted to the wearer's eyes. Contact lens wearers need to undergo eye examinations more frequently in order to detect and prevent any problems that may be developing. If contact lenses are prescribed and fitted correctly, the chances of such problems developing are very minimal.

Frequent Replacement Contact Lenses (Disposables)

Soft contact lenses are the type most frequently prescribed. Soft contact lenses are intended to be replaced more frequently and at shorter intervals. Frequent Replacement Contacts are usually replaced daily, 2 weekly or monthly. The short intervals between replacements ensure that the lenses are cleaner and healthier as they are disposed of and replaced before any harmful deposits can build up on the surface of the lens. Frequent Replacement Contacts can provide for better vision but are typically made from materials that tend to wear out more quickly. Therefore, it is important that contact lens replacement schedules be strictly followed.

Caring for your Contact Lenses

Contact lenses must be cleaned and disinfected after every wear unless they are due to be disposed of and replaced. Poor hygiene and the wearing of contact lenses for swimming are two of the most common problems associated with wearing contact lenses and often lead to eye problems, primarily infections. It is always best to consult an optometrist or ophthalmologist about the best care procedures and wearing schedules applicable to your prescribed lenses. Typically, caring for contact lenses involves two main procedures:

1. Cleaning the lenses

Cleaning your contact lenses is an important step as it prevents any unwanted deposits from building up on the surface of the lens. Contact lenses must be cleaned whenever they are removed from the eye, regardless of the duration or environment in which they are worn. In effect, deposits can start building up on the lens immediately on contacting the eye. This is because the deposits are composed of protein and lipids from the tears. The build up of these deposits can cause the lens to become uncomfortable and less effective. In addition, protein and lipid deposits can enable microorganisms to attach to, and reside on the lens' surface.

Contact lenses must be cleaned with an appropriate cleaning solution. These are special lens cleaning solutions and may vary depending on the type of contact lens. It is always best to consult the lens manufacturer and an optometrist as to the best solution suited for your particular contact lenses. Usually, the lenses are cleaned by rubbing them with a finger as they rest on the palm of the other hand. After cleaning, the lenses are rinsed with a sterile saline solution, or with contact lens multi-purpose disinfecting solution.

2. Disinfecting the lenses

Disinfecting the lenses is an essential step in order to destroy any microorganisms that may have attached to the lens surface. Failing to properly disinfect the lens can lead to bacteria and other microorganisms reproducing and transmitting to the eye on re-wearing the lens.

Lenses are disinfected with special disinfection systems. Again, these systems may vary depending on the type of lenses used. It is therefore important to consult an optometrist/ophthalmologist as to the most suitable disinfection system for your contact lenses.

Wearing Schedules (Frequency)

Wearing contact lenses for periods longer than they are intended is one of the common causes of eye problems amongst contact lens wearers. It is very important that a contact lens user follows their optometrist's recommendations and advice as to the amount of time they are to wear their contacts. Nowadays, contact lenses fall mostly within two categories:

1. Day wear

Day wear contact lenses are most commonly used. These lenses are inserted in the morning and removed at night. Day wear contact lenses' replacement frequency can vary from one day to one month. As mentioned previously, the lenses must be cleaned and disinfected before being worn again.

2. Extended wear

Extended wear contacts are a newer type of lens using materials that allow a large amount of oxygen to flow through the lens. This allows the wearer to continue to wear the lenses even while they are asleep. Extended wear contacts can typically be worn for up to 30 days continuously and without having to remove them, hence the name 'Extended Wear'.

Extended wear contact lenses may not be suitable for everyone, therefore, it is extremely important to consult your optometrist before using this type of lens. Never sleep in your lenses unless your optometrist or ophthalmologist has advised you it is safe for you to do this.

Eye Examination

Contact lenses should be obtained only after a proper prescription is issued by an optometrist or ophthalmologist. These professionals take various factors into account when prescribing contact lenses. Refractive error correction is the prime objective, however, an optometrist will also ensure that the lenses are unlikely to cause injury to the wearer's eyes. Contact lenses are placed in direct contact with the eye surface as well as the eye lid that needs to ride over them without causing any discomfort to the wearer. Because contact lenses sit directly on the eye surface, an optometrist will assess whether it is likely for the lens to provoke any reaction from the eye or immune system of the wearer.

Prescription

To make a prescription for contact lenses, the optometrist follows a lens prescribing procedure which involves several steps. Firstly, the optometrist assesses the health of the eye and measures the degree of any refractive errors that need to be corrected. After determining the level of the health of the eye, the optometrist discusses the issues associated with the use of contact lenses with the patient including their visual needs, life-style and other issues that may influence the recommendation as to the type of lenses best suited for the patient. Then, the optometrist takes eye measurements including the curvature of the front surface of the eye so that the prescribed lenses sit on the eye surface without causing any discomfort to the wearer. Once the lens measurements are determined, one or more trial lenses are placed on the eye until the best possible lens fit is determined. Once this has stage been reached, the optometrist makes the prescription and the lenses are ordered.

Initially, these will be preliminary lenses and the patient is introduced to the proper way of inserting them on the eyes as well as cleaning, disinfecting and storing. Often, the optometrist will perform a subsequent examination after a week or two to assess whether the lenses are performing well and to assess each eye's response and any reaction to the lenses. If any problems are detected, it is sometimes necessary to alter the prescription to avoid any complications. Altering the prescription may not necessarily mean altering the strength of the lenses, but may involve changing the type, frequency or make of the lenses.

After-care

Contact lens wearers need to have eye examinations regularly. Although it is rare, complications may develop suddenly even in patients who have been wearing contacts for lengthy periods of time. Frequent eye examinations can help detect any such complications and deal with them at an early stage. This is particularly important as eye health problems, including infections, can lead to serious and permanent damage. Therefore, regular eye examinations are the best insurance a contact lens wearer can take. So contact lens wearers should have an eye examination at least once each year, or more frequently depending on the type of lens being worn.

Basic Hygiene Rules

1. Thoroughly wash your hands prior to handling contact lenses.

2. Never use tap water on contact lenses.

3. Rinse any container used to store contact lenses daily with contact lens solution.

4. Replace the contact lens container at least every three months.

5. Wear goggles if swimming whilst wearing contact lenses.

6. Use fresh contact lens solution every day to clean and/or store weekly / fortnightly / monthly / extended wear contact lenses.

7. Avoid wetting contact lenses with water when in the shower or bath.

8. Do not sleep in extended wear contact lenses if you or someone in the household has a cold.

9. If you experience redness, soreness or irritable eyes, take out your contact lenses and seek advice from your eyecare provider immediately. This is particularly important if the symptoms persist, and of course, don't sleep whilst wearing extended wear contact lenses if any of these symptoms are present.

10. Saline is NOT a disinfecting solution, so contact lenses must never be stored in saline.