Types of Contact Lenses

Types of Contact Lenses

Contact lenses are a useful alternative to wearing glasses and having refractiive surgery. We discuss them in three broad categories, listed below.

- Disposable contact lenses

- Leave-in (extended wear) contact lenses

- Rigid gas permeable contact lenses 

Contact lenses are worn on the eye surface and need to be cared for correctly to reduce the risk of eye infection.

 


  • Disposable Contact Lenses

Disposable contact lenses are soft lenses which are designed to be replaced on a regular basis - daily, fortnightly or monthly. Disposable lenses have been around since the early 1990s and the majority of new lens fits in the twentyfirst century are for disposable lenses. This means that many of the problems that wearers experienced when contact lenses were replaced annually or less often are rarely seen now. The more often a lens is replaced, the less dirty and deposited it becomes In addition, twentyfirst century materials minimise problems related to oxygen deprivation due to their superior oxygen transmissibility.

Daily disposable contact lenses are the ultimate in disposable lenses since they are thrown away after only one day's wear. They don't need to be cleaned ard offer exceptional convenience and good value for money. Lenses which are replaced on a fortnightly or monthly are usually a slightly cheaper option and are available for a slightly wider range of prescriptions, including multifocals. They must be cleaned and disinfected after each wear.


  • Rigid Gas Permeable Contact Lenses

Rigid gas permeable contact lenses are non-disposable lenses made of rigid materials. They're custom made and they're particularly useful for high prescriptions, unusual eye conditions and irregular eye shapes. Rigid lenses are used for for fitting people who have had corneal grafts and people with keratoconus. They provide excellent clarity of vision, and are an option for less exotic prescriptions too although they require a longer period of adaptation than soft lenses. Orthokeratology (a process of reshaping the eye surface overnight in order to see clearly during the day without contacts or glasses) involves wearing rigid gas permeable lenses overnight. Gas permeable contact lenses offer excellent long-term corneal health since they allow almost as much oxygen reach the eye surface as not wearing a lens.

Nearly all rigid lenses in the twenty first century are made from gas permeable materials and should be replaced every year or two. Hard lenses made last century have a very long life span but provide less oxygen to the eye surface. Wearers of all kinds of contact lenses should have eye exams annually.

 


  • Leave-in (Extended Wear) Contact Lenses

Leave-in (extended wear) contact lenses are designed to be worn continuously, (usually for up to thirty days and nights) and then replaced. They are a very convenient option since they don't need to be put in or taken out daily, and generally don't need cleaning. They offer good vision without glasses around the clock and almost eliminate the need for contact lens solution. They are available in a wide range of prescriptions, including multifocals.

It's important to be aware that wearing lenses overnight comes with a higher riskof serious eye infection than wearing your lenses only during the day does, so you need to discuss the pros and cons fully with your contact lens practitioner. If you're wearing this kind of lens it's particularly important to have regular checkups and to take immediate action if you have a red or sore eye.

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