If you and your doctor decide that contacts are for you, there are a number of options to choose from.
Soft contact lenses. Majority of patients desire and wear this type of contacts. Soft contact lenses are thin, water loving polymer-plastic lenses that conform to the shape of your eye. Soft contacts contain between 25 percent and 79 percent water. Water provides wetness to the lenses, which makes them very comfortable and easy to adapt to. They're more flexible than rigid gas-permeable contacts and are more comfortable from the first wearing. These lenses have a shorter adaptation period and tend to stay in place better, making them a better choice for active lifestyles and sports. Often they are as effective in correcting some vision problems, including higher degrees of astigmatism, as are rigid lenses. They can be easily worn part –time and interchanged with spectacles. Most soft contact lenses today are disposable.
Rigid gas-permeable (RGP) lenses. These lenses are made of harder plastic materials that don't contain water. Although they're not as flexible as soft contacts, they allow oxygen to pass through to the cornea just like soft lenses. They may represent the only solution to provide a patient with excellent vision for certain conditions: such as very high astigmatism and distorted corneal shape caused by keratoconus or corneal irregularities or scars. RGP lenses become more comfortable for most people after a period of adaptation. RGP lenses are easy to insert and remove, and care for. The disadvantages of RGP lenses: they may dislodge off the center of your eye more easily, and may become very uncomfortable in windy conditions if a particle of sand or dust works its way under the lens. And, to achieve maximum comfort with RGPs, you have to wear them every day. If you don't wear your soft lenses for several days, they'll still be comfortable when you put them on a week later. If you don't wear your RGPs for a week, you'll probably need an adjustment period before they're comfortable again. In addition, RGP lenses have some molding effect on the cornea, which results in a changing prescription, so that interchanging them with spectacles may be more difficult.
As you age, you may experience problems focusing on objects that are up close — a condition called presbyopia. Contact lens options that correct this condition also exist.
- Monovision. This is the most common option for people with presbyopia, in which you use a contact lens with the reading prescription in one eye and a lens with the distance prescription in the other eye. The perception usually adjusts to this, and many people feel comfortable with the combined vision from both eyes. The distance vision lens is usually worn in your dominant eye.
- Modified monovision. This option entails wearing a combination of contact lenses that is designed to deliver the best vision at the patient's most frequent working distance, so as to minimize the dependence on spectacles This may be a good option if you spend a lot of time using a computer. Monovision and modified monovision options are available in both RGP and soft lenses.
- Bifocal lenses. Today's bifocal lenses are available in either soft or rigid gas permeable materials. These lenses feature two prescriptions on one lens: one to correct distance vision, if that's needed, and the other to correct near vision.
Three different designs for bifocal contact lenses exist: simultaneous, concentric and alternating vision.
Simultaneous vision designs fit centered on your cornea with both the distance-vision and near-vision prescriptions within the pupil area. Your own visual system learns to interpret the correct prescription choice depending on the distance you're viewing.
In a concentric design, the center portion of the lens contains the distance prescription and the outside portion contains the near prescription, or vice versa.
Alternating vision designs work much like a bifocal eyeglass lens, in that the top of the lens has one prescription and the bottom has the other. That design is commonly used in rigid gas permeable bifocals and has a high degree of success. It is also the most sophisticated, high expertise requiring fit. Our doctors have successfully fitted hundreds of patients with these highly complex lenses. These bifocal options require accurate and professional fitting, and getting used to them takes some time. Not everyone is able to use bifocal contacts. Some people prefer to wear contact lenses that correct their distance vision to normal and use reading glasses over the contact lenses for near vision tasks. To maximize a presbyopic patient's chance of success, the expertise and experience of the doctor is of paramount importance. Our patients can be sure that their doctors have both.
Contact lenses can be worn for a limited period of time before needing replacement. Gas-permeable lenses may be worn for 1-3 years. Traditional soft lenses are only worn for about a year. Today, most of the soft contact lenses are disposable and designed for replacement frequency ranging from once a month to every day. The more frequently you replace your contact lenses, the healthier and more comfortable your eyes are likely to be. Substances like protein, calcium, and lipids — found naturally in your tears — can build up on your lenses. These deposits make your contacts less comfortable than when they were new, and can also make your eyes more prone to infection.
Disposable soft contact lenses, just as traditional, can be worn on a daily wear basis (removing them nightly) or on extended wear basis. Extended wear lenses are soft lenses that are approved for more than 24 hours of continuous wear. They are designed to provide adequate oxygen to your cornea even while you sleep, so they can be worn continuously for up to seven days before they need to be removed for cleaning. In 2001, the Food and Drug Administration approved new extended-wear lenses that can be prescribed for extended overnight wear up to 30 days and nights. These new lenses are made of super permeable silicone hydrogel, which allows far more oxygen to get through to the cornea than do ordinary extended-wear lenses.
A thorough examination and fitting by an experienced professional is crucial to the successful use of contact lenses. "The problem with mail-order lenses, for example, is that you can just keep buying them year after year and no one ever looks at your eyes to see if there have been any changes or adverse reactions that you may not be aware . Regular follow-up is as important as getting a correct fit to begin with. If you're a regular contact lens wearer, see your doctor annually for an eye exam and a contact lens evaluation — more often if you have any problems.
Keep in mind that, as you age, your eyes tend to get dryer. This may limit the length of time you can comfortably wear your contacts. If your eyes are dry without contact lenses, they will feel even dryer with them. However, new developments in the lens material and designs have resulted in improved comfort levels for some people with dry eyes.
The cornea — the clear tissue that overlays the pupil and iris — needs a steady supply of oxygen to stay healthy and function properly. Problems related to the use of contacts can stem from reduced oxygen to the cornea. Although the vast majority of people who try contact lenses have good results, problems — some of them potentially sight-threatening — can develop:
- Overuse. Wearing contacts for too long a continuous period deprives your cornea of oxygen. You may experience blurry vision, pain, excessive tearing, redness and light sensitivity. If this occurs, remove your lenses immediately.
- Corneal neo-vascularization. Oxygen deprivation causes tiny blood vessels to grow into the clear tissue of your cornea. This is an indication of corneal stress and, in extreme cases, may cause scarring of the cornea and potentially clouded vision, and may necessitate switching to another type of lens or discontinuing the use of contacts altogether.
- Corneal warping. Prolonged contact lens wear may produce gradual and unpredictable changes in the contour of the cornea, resulting in uneven or fluctuating vision. This is most common among wearers of standard hard lenses, but also can occur with soft contact lens wear. The cornea usually regains a stable and regular shape after discontinuation of contact lens use, but this may take weeks or even months.
- Giant papillary conjunctivitis (GPC). This is a fairly common allergic disorder among soft lens wearers. Your eyes may itch and emit a discharge, and your contact lenses may be subject to excessive movement. Blurred vision may result. This condition is more common among people whose lenses are old or have developed a protein layer on the surface. You may have to stop wearing them for awhile. The change in your solutions or may be essential to treating this condition. This is less likely to occur with daily disposable soft contact lenses.
Avoid many of the problems associated with the use of contact lenses by practicing proper hygiene:
- Wash, rinse and dry your hands before handling your contacts. Use mild soap. Never use tap water, saliva or homemade solutions to clean or wet your contact lenses.
- Use quality lens-care products according to your eye doctor's directions. Don't reuse solutions.
- Some bacteria can penetrate certain soft contacts. After cleaning your lenses by rubbing each lens in the palm of your hand for a few seconds, soak the lenses in a disinfecting and cleaning solution according to product instructions before wearing them again. This kills most of the remaining bacteria.
- Adhere to wearing and replacement scheduled prescribed by your doctor.