Over the last decade the contact lens industry has seen an explosion in sales as the different shapes, sizes, colours and designs of the contact lenses have grown. Today, millions of people are choosing to wear contacts instead of glasses. Some are skeptical though, that a tiny disc of different material and colour can be worn on the eye daily and still provide clear comfortable vision. So read on to learn more about the different types, coloured lenses, how to take care of and health warnings about contact lenses.
WHAT ARE CONTACT LENSES?
Definition: A contact lens is a corrective, cosmetic or therapeutic lens placed on the cornea of the eye.
Leonardo da Vinci described and sketched the first ideas for contact lenses in 1508, but it took more than 300 years before lenses were actually worn on the eye.
Contact lenses usually serve the same corrective purposes as spectacles, but are lightweight and almost invisible. They are thin optical discs, worn directly on the eye and are held in place by layers of tears. The contact lens acts as an extension of the eye itself, correcting aberrations that cause a variety of defects.
‘Clear’ prescription contact lenses have a faint blue colour called a visibility tint to make the lenses more visible when immersed in cleaning solution. Cosmetic contact lenses are deliberately coloured to alter the appearance of the eye. Most contact lenses are surfaced treated with a UV coating to reduce UV damage to the eyes natural lens.
CONTACT LENSES or EYEGLASSES
Contact lenses are worn for many reasons, often because of their practicality and appearance. When compared with spectacles, contact lenses are less affected by wet weather, do not steam up and provide a wider field of vision. They are suitable for a number of sporting activities. Additionally, certain eye conditions likekeratoconus and aniseikonia cannot accurately be corrected by spectacles and contact lenses are a much better option.
Some other reasons to wear contacts are:
- The advances in contact lens technology in recent years have given people a great amount of freedom and comfort.
- Contact lenses move with your eye, allow a natural field of view, have no frames to obstruct your vision and greatly reduce distortions.
- They do not fog up, like glasses, nor do they get splattered by mud or rain.
- Contact lenses do not get in the way of your activities.
- Many people feel they look better in contact lenses.
- Today, almost all corrections can be done with contact lenses and more eye care professionals are recommending their use to a wide variety of patients.
TYPES of CONTACT LENSES
Disposable soft contact lenses are normally worn from 2 weeks up to 30 days and then discarded. They are made of soft, pliable plastics that allow oxygen to reach the eye. They are easy to adapt to and comfortable to wear and are available in almost all prescriptions. They require daily removal and cleaning.
Daily wear soft disposable lenses are worn for a single day and then discarded. The major advantage of this is that there is no lens cleaning or lens care required and new lenses are worn everyday. The disadvantage is that they are not appropriate for all prescriptions and may not provide sharp enough vision for some people.
Extended-wear lenses are soft and can usually be worn continuously for up to 30 days without being removed.
Rigid gas permeable lenses (hard) are made from slightly flexible plastics that allow oxygen to pass through them. They may provide sharper vision than soft lenses and can be used to correct most vision problems. However, they do take longer to get used to them (approx. 2 to 4 weeks).
Spherical contact lenses are soft or hard lenses that contain a single prescription power.
Aspheric contact lenses are used by people with only slight astigmatism.
Toric contact lenses are soft or hard lenses that combine a spherical and cylindrical component to correct astigmatism. They are usually thicker in one area than another so they can stay in the correct position on the eye.
Bifocal or multifocal contact lenses work like bifocal or multifocal spectacles. They provide sharp vision up close and at a distance. These are usually given to patients over the age of 40.
Orthokeratology lenses are also called Ortho-K or reverse geometry lenses and are a non-surgical method of reshaping the cornea. They are worn overnight and they progressively adjust the cornea’s shape, correcting the vision defect. The effect lasts about 12 hours before reversing itself.
COLOUR CONTACT LENSES
Coloured contact lenses have become very popular across the globe, especially in these times when it is important the way you look and to always change something about your looks. Coloured contact lenses are NOT for medical purposes; they are used to change the way a person looks i.e. purely cosmetic and decorative reasons. Coloured contact lenses have become a fashion accessory like a new bag or shoes, and they are also representing a way to have fun.
Coloured contact lenses come in many types and many styles. For dark coloured eyes, blue, grey, green and hazel are recommended. For light coloured eyes, all shades of blue, green and gray work well. There are also contact lenses that imitate the eyes of cats, or contact lenses that make you look like a vampire. The choice here is endless and can be great fun. They are becoming increasingly popular with teenagers and young adults as they seek to find their most appealing eye colour /complexion / hair colour match. Increased technology and supply has led to coloured contact lenses becoming increasingly affordable to many.
The coloured contacts are as safe as normal clear contact lenses and it is important to clean them daily, to follow exactly the rules regarding their wearing and NOT borrow them to another person.
HOW TO TAKE CARE of CONTACT LENSES
Wearing contact lenses DOES restrict the amount of oxygen passing through the cornea and if a contact lens is worn for too long it may cause blurry vision, pain and redness. Improper cleaning and care of contact lenses can cause bacterial infections which can lead to other eye diseases. Contact lenses require greater care than spectacles because they come into direct contact with the eye. Whatever is on the lens-dust, pollen, bacteria and chemicals, also reaches the eye surface.
Always follow the optometrist’s directions, as well as manufacturer’s instructions on cleaning methods. Your optometrist should also be consulted about changing brands of solution.
Avoid swimming with contact lenses because of the risk of bacterial contamination from the pool or sea water.
Contact lenses have to be cleaned daily and should be removed for sleeping.
Potential Risks in Wearing Contact Lenses
Corneal ulcers can occur from long term contact lens use. Ulcers can cause scarring, lead to vision loss, including partial or complete blindness.
Treat your lenses with care, follow the instructions of your optometrist, clean daily, limit your wearing time and they will reward you with great comfortable vision.
SIGNS OF POTENTIAL PROBLEMS
It is normally not difficult to wear contact lenses. However, there are times where problems are experienced. If any of the following happens, contact your optometrist as soon as possible:
- Sudden onset of blurred vision,
- Red, irritated eyes
- Uncomfortable lenses
- Pain in and around the eyes
Following your optometrist’s advice and scheduling regular follow up visits will prevent most problems.
FAQ ABOUT CONTACT LENSES
Here are some the other frequently asked questions I get as an optometrist who prescribes contact lenses:
1. At what age can I wear contact lenses?
With the variety of lenses now available, more people can wear contact lenses. Children as young as 8 years can wear contact lenses if they are responsible enough and properly trained. Contact lenses are normally good for their self esteem and prevent them from being teased at school. They would require more frequent follow up visits.
2. If I wear bifocals/multifocals, can I wear contact lenses?
There are many options for people who are over the age of 40 and are affected by presbyopia. Presbyopia occurs when, as part of the natural aging process, the eye’s crystalline lens loses its ability to bring close objects into clear focus.
These people would require a bifocal or multifocal contact lens to provide clear vision at distance as well as near. Another option is Monovision. This means wearing a contact lens for near vision in one eye and, if needed, a lens for distance in the other eye. A third option would be a combination of contact lenses and reading glasses.
3. If I have astigmatism- can I wear contact lenses?
Many people with astigmatism are under the impression that they can’t wear contact lenses. But nowadays, toric lenses are available and these work perfectly for astigmatism.
Astigmatism is a long word for distorted vision as a result of having an irregularly shaped cornea. Toric lenses have the ability to correct this defect and they also have a stabilizing mechanism that keeps them flush on your eye when you blink.
4. Can contact lenses damage my eyes?
If you have never worn contact lenses before, putting something in your eye can seem a daunting task. But millions of people around the world wear contact lenses without any problems. As long as you follow the basic cleaning steps, you could be one of them. Colour contacts and ‘crazy lenses’ normally arouse curiosity and envy among your friends. It is important to never, ever share them as this could cause a nasty infection.
5. What if the lens goes behind my eyeball?
It is impossible for a foreign object like a contact lens to go behind the eyeball. The worst that could happen is that the contact lens may slide and get misplaced under the eye lid. If this happens, move the eyes in the direction of the lens, which will slide back into place.
6. Is it better to get my contact lenses from an Optometrist or Ophthalmologist?
An ophthalmologist is a medical doctor and specializes in the eye. They are concerned more with eye surgery and treating eye diseases. There are a few who would specialize in contact lenses. An optometrist is trained to perform eye examinations and prescribe vision correction devices like spectacles or contact lenses. Both can give you the contact lenses you need. Find one you’re comfortable with and be assured that you are in good hands.
Health Caution: Many sites on the internet offer to buy contact lenses online. Almost all eye care professionals advise against this. Direct contact with your optometrist and regular check ups are of utmost importance.
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