Contact lenses that you can wear while you sleep—this earth- shattering concept arouses no less interest and excitement than the Pill did when it was first introduced. This is the glamour lens that everybody wants to know about and have, and is probably the lens of the future. Like the Pill, which forever altered our sexual standards, the extended-wear contact lens promises to usher in a new era and change our attitudes toward visual correction. But the similarity doesn’t end there: Though this lens seems to be the answer to every contact lens wearer’s prayers, it has not yet been perfected. It is definitely not for everyone, and some practitioners are reluctant to prescribe it at all.
Canada, Australia, and Europe enjoyed several types of extended-wear contact lenses several years before we did. However, there is no Food and Drug Administration in those parts of the world, and because of this lack of strict monitoring control and quality, these lenses have posed a health problem, especially as related to corneal complications. Read the rest of this entry »
The eventual comfort of gas-permeable lenses lies somewhere between that of soft and hard lenses. Novice contact lens wearers will experience some of the initial foreign-body sensation similar to that of the hard lens, but the point at which they can be worn full time comes much sooner. In addition the number of hours meant by “full time” is longer: sixteen hours is common, as opposed to the eight that’s usual for conventional hard lenses. Some who switch from conventional hard lenses to gas-permeable lenses are not initially impressed with the difference in comfort and wearing time, but this gradually improves as the eye recovers from the effects of wearing (and overwearing) their original hard lenses. Read the rest of this entry »
Though the eventual comfort level is somewhere between that of a hard lens and a soft lens, a few wearers may complain of an initial scratchy sensation. Because of the nature of the materials, the lenses are often made slightly larger than conventional hard lenses. There are also difficulties in modifying and adjusting the fit of some of the lenses, and these lenses cannot be fenestrated successfully to relieve any dry-eye problem.
Astigmatism is not corrected quite as well as it is with conventional hard lenses. However, vision is appreciably sharper than with soft lenses, even the toric soft contacts.
Gas-permeable lenses are more expensive than hard lenses; they cost even more than conventional soft lenses. But since they are nearly as durable as hard lenses, replacement is less frequent. The lenses can, however, be chipped and scratched. Warping may occur with time, though damage is minimized with proper handling. CAB lenses can be stained by eye makeup and hairspray. The surface deposits that form easily on the silicone lenses can’t always be removed completely with the usual cleaning and soaking solutions. This is less prevalent with the CAB lenses.
The lenses are difficult to make and delivery time may take a few weeks. The right lens cannot be dotted to avoid confusing the right and left lenses.
Contact Lenses Care .
