Seeing decade by decade
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eeing decade by decade
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n 1959, I was 11 years old when one of my teachers determined that I needed to be examined by an optometrist who confirmed that I needed eyeglasses. The optometrist found that my eyes were myopic, that is, that I could see clearly close up, but hardly at all at any distance. I was shortly fitted with a wonderful pair of eyeglasses that allowed me to see and read at a distance as well as close-up. If you’ve seen pictures of U.S. Senator Barry Goldwater in the 1960s, then you know what my first set of eyeglasses was like. My first set of lenses were glass (probably crown glass), and very thick. Not quite as thick as the bottom of coke bottles, but still very thick. The frames were the sturdy, black plastic frames. I cannot tell you how many times the frames broke in those early years, but I had extensive time periods when the frames were held together by some form of tape. At some point in the 1960s, my glass lenses were replaced with plastic lenses that were advertised as being safer because they were “shatterproof.” However, another advantage of plastic lenses over glass is that plastics commonly used for eyeglasses generally have a higher index of refraction than glasses used for eyeglasses, so that lenses with the same optical curvature could be achieved in plastic lenses that were lighter weight than the corresponding glass lenses. Frames also evolved during that time period into lighter weight, but sturdier. In the late 1960s and early 1970s, nothing would work for me but thin wire frames, which I believe were made of a base metal plated with a thin gold coating. I think that this was during the time period that I had shoulderlength hair, a Nehru jacket, and bellbottom pants. (God, I hope that none of the photographs from that era survive today!) Although I thought at the time that the wire frames looked good, they certainly weren’t very practical in terms of durability. Today, there are wire frames made of stainless steel, titanium,
and titanium alloys that are somewhat more durable and more flexible. At some point, eyeglass manufacturers developed lenses in polycarbonate materials that are higher in index of refraction than plastic, so that thinner, more lightweight lenses could be manufactured. Polycarbonate lenses are also more resistant to shatter than the original plastic lens materials. I note that lens manufacturers are careful these days not to claim that materials are “shatterproof,” only that they are more shatter-resistant. Today, there are more than a dozen different plastic materials and a half-dozen or so glass materials that are used in lenses for eyeglasses (e.g., see http://en.wikipedia.org/wiki/ Corrective_lens). In my mid-40s, I noticed that it was becoming harder and harder to read at close distances. Sure enough, a visit to my optometrist confirmed presbyopia, the hardening of the lens that occurs with age that increases the difficulty to focus, particularly on objects close to the eyes. At first, I had two pairs of glasses, one for read"Seeing decade by decade" i
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