A Basic Introduction to Contact Lenses
Contact Lens types available
Soft Contact Lenses are hydrophilic or "water loving". Their water content ranges from 24% to 80% for different applications. Usually the higher the water content the higher the oxygen transmission, except for silicone hydrogel lenses. Soft lenses are divided into two main groups – Conventional and Disposable.
Conventional Soft Contact Lenses or non-disposable contact lenses are expected to last for 12 to 18 months of normal wear. They are sold individually, and are often custom made for each person. They require more lens care than disposable contact lenses – there are usually separate solutions for cleaning, rinsing, disinfection and storage.
Disposable Soft Contact Lenses offer better eye health through regular lens replacement before lens aging and protein deposits on the lens surface can develop. Always comply with the replacement schedule advised by your optometrist. Disposable contact lenses are available in daily wear, 2 weekly replacement, monthly replacement or 30 day continuous wear. If you are wearing a monthly lens it will be good for 30 wears, but needs to be discarded after 3 months even if you have not worn it 30 times. These are sold in multi- packs for each eye. They have simple one step lens care cleaning and storage solutions.
Rigid contact lenses or RGP lenses have zero water content, however because of the chemicals in the new gas-permeable materials they do allow oxygen to pass through for the eye’s health. Rigid contact lenses are often called hard lenses.
Spheres or spherical lenses are standard contact lenses they do not correct astigmatism.
Toric contact lenses correct astigmatism. These have a cylinder and axis (like a spectacle lens) and a special feature to keep the contact lens stable without rotating it out of position. These lenses are more complicated in design and are specific to the individual patient and often need to be custom made.
Bi-focal and Multi-focal Contact Lenses have and add (like a spectacle lens) which is an extra adjustment which will allow you to see near and far.
Clear or Tinted There are a number of different tint options available ranging from a visiblity tint to an opaque tint.
A Visibility Tint makes is easier to see and handle the contact lens, it is often pale blue or green and is usually included in lenses at no extra charge.
Transparent Tints also known as enhancer colour, designed to specifically to enhance and brighten the natural eye colour.
Cosmetic Tints are used to change eye colour e.g. make brown eyes blue, and for matching eye colour for those with 2 different coloured eyes.
Often the main motivation to wear contact lenses is cosmetic, to avoid the need for spectacles. However many spectacle wearers are choosing to wear disposable contact lenses for sport or a special occasion. Contact lenses may even be worn with no prescription (Plano) simply to change eye colour. Nevertheless, they are still a prescription device that sits on a healthy eye and must only be fitted by a qualified eye care professional. Nothing is more precious than your sight and you should never put it at risk.
Although all eyes look pretty much the same, in reality everybody's eyes are slightly different. Eyes come in a variety of shapes and sizes and it is essential that anyone wanting to try contact lenses should visit an optometrist for a contact lens consultation and fitting. After being fitted for contact lenses you will be given instructions on how to properly insert and remove your contact lenses without causing any damage to your eye, you will also be given advice on lens handling, which will help you get the most out of your lenses without damaging them. If you wear a damaged contact lens it can irritate your eye and cause a nasty eye infection.
All contact lenses have a different wearing schedule according to the lens and the patient, so it is very important that you follow recommendations made by your optometrist. If you are experiencing any discomfort or eye redness, remove the contact lens immediately and consult your optometrist.
Borrowing contact lenses, or obtaining them without a prescription, could lead to serious vision problems due to incorrect fit. Even if you've been wearing contacts for years, it's a good idea to have your optometrist check your prescription to make sure that your lenses offer the best possible fit for your unique eyes.