Eyeglasses and contact lenses are now very ordinary. Costs can range from cheap to pricey, partly as a result of vanity and marketing. Ignoring cosmetics and humor, the basic function for both lens types is to correct degraded vision.
Yawn. Big deal. So What?
Any reader older than about 50 probably remembers what spectacles used to be like. Heavy frames, thick and heavy glass lenses, often very uncomfortable, and far too easy to damage.
So a few developments in different kinds of materials led to some very nice improvements.
Plastics evolved that were very clear, light weight, and with higher index of refraction than glass. All this meant lenses could be thinner and far less heavy in plastic than in glass. Break resistance came as a free bonus. Of course, it is easier to scratch plastic than glass, but coatings have decreased that problem.
Frames were originally made of wire or such natural things as tortoise shell, and could be expensive. Development of break resistant plastics brought down frame prices, but not weight. Metal frames tended to be heavy or thin and easily bent. Modern alloys permit light weight metal frames with both flexibility and shape memory.
The result of such developments is spectacles that weigh a small fraction of the best available about a generation ago.
And then contact lenses arrived. The originals were made from blown glass bubbles and covered the visible portion of the eye (sclera). Then came those plastics that were very clear, light weight, and with higher index of refraction than glass. Hard or rigid lenses became practical in the 1930s, but comfort was far from perfect. Later various materials evolved for lenses that could bend with the shape of the cornea. Small grooves or holes improved the flow of tears and oxygen in hard lenses, then came materials that were gas permeable and hydrophilic.
Modern contact lenses take very little adaptation time, have negligible irritation for most users, and can be worn for long periods. Recent studies, however, strongly suggest that even long-wear lenses be removed at least a few hours per week. With declining prices, disposable lenses offer a nice alternative to careful lens cleaning.
Not every vision problem can be solved by contact lenses, but we still have those modern spectacles. Laser eye surgery can not be reversed, and can not prevent further eye aging. Contacts and spectacles are far more sensible than LASIK for making your eyes young again.
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For more articles about safe and enjoyable use of contact lenses and spectacles, see 3daycontacts.com/articlelist.htm by Dr. Don Miller.
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