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Contact lenses are the top choice for a growing number of people. There's probably one that is right for you. Soft Contact Lenses - SCL - Soft contacts can be classified in a number of ways. There are three main divisions- (1) The disposal cycle or useful lifetime of the lens; (2) Daily wear vs. extended wear (1-30 day continuous wear) FDA approval; and (3) The prescription they correct (i.e. nearsightedness, astigmatism, bifocal, etc.). Most divisions overlap each other and since extended wear is becoming less common, it is easiest to start with the disposal cycle classification. Consumers and the contact lens industry are primarily, if not exclusively, interested in disposable lenses. Secondarily, we look at the oxygen transmission (Dk value) of the lens polymer. Extended wear lenses have higher Dk values and are FDA approved for overnight wear (although at increased health risk to the patients). We're still very concerned with oxygen transmission and generally use the higher value lens whenever possible to give daily wear patients the added comfort and safety margin benefit.
Some of the newest soft contact lenses are called silicone hydrogels;
they allow six times more oxygen transmission than traditional
disposable lenses. Some of these new lenses can be worn up to 30
days of extended wear. So if we look at disposal cycles we have- "Daily Disposables" for 1 day, single use and disposed of each night. There are 3 brands at present to correct simple near- or far-sighted prescriptions. You can think of these as the ultimate in convenience and eye health. "Disposables" meaning 1-2 weeks of use before disposing. This is by far the most common class of lenses currently being prescribed and most are extended wear materials. New releases even include good bifocal and astigmatism correcting lenses in this class, as well as, tints to turn "your brown eyes blue" or other shades. It is very often the best blend of comfort, eye health and value. "Frequent Replacement" lenses of 1-3 month cycles. These often include more specialty lenses like bifocal or astigmatism lenses. This is a good option for patients who are stepping down from traditional 1 year lenses. Many are extended wear materials and a few have tint options. "Traditional, or Non-Disposable" these lenses first introduced in the 70's last on average 6-12 months or longer. There are many daily wear, extended wear or tint options. This class, being the oldest, has the widest range of specialty and high prescription options but can become soiled over time decreasing comfort, eye health and vision. If soiled or lost, replacement can be costly. Rigid Gas Permeable - RGP - These are the new generation of the hard contact of the 1960-70’s and they have some of the best oxygen permeability of any contact. They are very durable and tend to give very sharp vision even to high prescriptions. Adaptation takes about one week. RGP’s are more likely to get dust trapped under them while wearing making them not as practical for sports or people in dusty environments. These are used almost exclusively on a daily wear schedule. They come in various colors and all are custom made. Once adapted to this lens we have little reasons to change to soft lenses unless comfort becomes a problem. Dr. Kirk and Dr. Crissman can help you determine which of these lenses best suits your lifestyle and meets your eye care needs. |
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