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Made of gel-like plastic, soft contact lenses contain varying amounts of water (ranging from 25% to 79%). Soft contact lenses provide good initial comfort for first-time wearers but must be replaced often. Statistically, more than 80% of lens-wearers choose soft contacts (Mayo Clinic 2005). The water in soft contact lenses is necessary in order for oxygen to pass through the lens and reach the cornea. This also makes the lens comfortable and easy to adapt to in addition to aiding the lens to remain in place easier than gas permeable lenses. Soft contact lenses the choice selection for those with an active lifestyle.

When selecting soft contact lenses, take note of the fact that although daily wear soft contact lenses are not as durable as gas permiable lenses, they are more durable than disposable lenses. It should be noted that soft contact lenses are not as effective when it comes to correcting certain vision problems such as high degrees of astigmatism. Consult your optometrist for further detail.

Gas permeable contact lenses may also be referred to as RGPs, or rigid gas permeable contact lenses. Gas permeable contact lenses should not be confused with hard contact lenses, as they differ in the fact that oxygen is let through to the eye when wearing RGP contact lenses. RGP contact lenses allow for more oxygen to pass through than traditional soft contact lenses as well. This can be attributed to the fact that RGP contact lenses are made out of silicone. Ultimately, this leads to more comfort for contact lens wearers and promotes the maintenance of a healthier eye. According to the FDA, approximately 16% of Americans wear RGP contact lenses. Additionally, the OK RGP contact lens, made by ConTEX, is the first lens designed to correct nearsightedness by temporarily reshaping the transparent tissue covering the iris and pupil (cornea).

Although one of the major downsides to choosing RGP contact lenses is the adjustment period, long term benefits such as crispness of vision (RGP contact lenses do not bend as easily when blinking), durability (due to being constructed out of heavier material) and reduced protein build up are positive points when comparing the value RGP contact lenses to soft contact lenses. RGP contact lenses can last for years as long as the strength in prescription does not fluctuate.

Gas permeable contact lenses should be a consideration for individuals who fit the following categories:
  • Patients with keratoconus who suffer from visual misrepresentation due to the extreme cone-shape of the cornea.
  • Patients suffering from presbyopia, due to the availability of gas permeable contact lenses in various bifocal configurations.
  • Patients with astigmatism, due to the provision of a more accurate field of vision over soft contact lenses.
  • Patients willing to overlook the adjustment period of gas permeable contact lenses due to being more discriminating of their quality of vision.
For patients who have an astigmatism, it is now probable that soft contact lenses can be provided to correct eyesight, where once, there was no choice but to wear gas permeable toric, or astigmatism correcting, contact lenses. Toric contact lenses cannot rotate when in the eye due to a special mechanism; they are split into two sections - divided by curvature - consisting of two different powers.

There are many more types of contact lenses, for a pair which best suit your needs, contact Dr. Soma Bose.
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