All About Contact Lenses

Different Types of Contact Lenses

There are various types of contact lenses available for vision corrections and cosmetic or fashion accessories. You may wear the lenses for correcting vision problems as well as for changing eye color and aesthetic purposes.

Contacts can be divided into several main categories based on what material they're made of, whether you can sleep in them, how often they need to be replaced, how they change the color of your eyes, and the type of refractive error they corrects. Here are details of each category.

Soft and Gas Permeable Lenses Material

Contact lenses come in soft (hydrogel or hydrophilic) and RGP (gas permeable) plastic material types. Soft lenses contain from 25% to 79% water and are very flexible. They are easy to adapt and are comfortable but may not give as crisp of vision as RGP's.

RGP lenses are the improved conventional "hard" lenses that are stiffer and smaller in diameter compared to soft contacts. You need a longer time to get accustomed to them. If you require a specialized prescription chances are gas permeable material can meet your vision correction and occupation needs.

Daily Wear and Extended Wear

The "wear" term refers to wearing time. This is about convenience in wearing contacts.

Daily wear lens is removed at night for cleaning and disinfecting. This lens type is healthier because the risks of eye infections, caused by reduced amounts of tears and oxygen that reach the cornea, are lower.

Some people don't like the hassle of inserting and removing contacts as well as caring for their lenses. They just want to put their lenses in and sleeping with the lenses on for a week at a time. The lenses that cater these needs are extended wear lenses. They are very convenient but some experts warn that the application is less healthy than daily wear lenses.

Flexible wear is a compromise between convenience and eye health. If you wear these lenses you may sleep in them but you can remove your contacts occasionally for lens care as well as for eye care.

Disposable, and Planned/Frequent Replacement Contacts

The above terms refers to replacement schedules, which is the safe wearing interval of contacts before you need to throw them away. For example, RGP lens is discarded after a couple of years. But soft lenses have various replacement schedules:

Daily (one-day) disposable -- replaced every 1 day
Disposable (extended wear) -- replaced every 1 week to 2 week
Frequent/planned replacement -- replaced every 1 month to several months
Conventional -- replaced every 1 year

Today disposable lenses become more and more popular because they are affordable as well as healthy for the eye. Depending on their replacement schedules you don't need to care for them every day. Disposable lenses for astigmatism correction or varying shades color contacts are also available in the market.

Colored, Special Effects and Toric

Colored contacts are available in non prescription as well as in spherical and toric designs that require prescription. They are available for cosmetic and fashion wear, which are usually "plano" or nonprescription type. If you wear colored lenses you will be able to match your costume with a pair of green or blue contacts.

There are many color lens designs that cater special occasions such as scary and fancy lenses for Halloween, or theatrical and special effects for film productions. The color effects may range from adding a little blue or green enhancement to the ones that completely change your eye colors. If you have astigmatism there is colored toric lens.

If you have astigmatism there are toric lenses that answer your needs. Toric lenses have as much variations as spherical soft lenses. They have both daily and extended wear schedules. There is also all range of replacement schedules from daily disposable to conventional lenses. Toric lens is also available in color.

Bifocal Contact Lenses

As you reach presbyopia age you may experience difficulties focusing on up-close object. But don't worry becoming too old to wear contacts; there are contact lens options that correct presbyopic eyes:

Progressive lenses correct your distance vision in the central part of the lens. And your intermediate and near distance visions are corrected with the outer regions of the lens. Some newer aspheric lenses are available in planned replacement and disposable modalities.

Multifocal or bifocal lenses correct vision with at least two powers. There are variations in bifocal lens designs. In concentric or annulus designs, the central part of the lenses correct near vision and the outer rings correct intermediate and distance visions. In translating contact lens designs you'll see a line separating the powers with distance vision on the top and near vision at the bottom.

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