Tuesday, October 5, 2010
Glasses That Provide for Both Farsightedness and Nearsightedness!
This is the second time I've come across an article talking about these very glasses, and I felt it necessary to talk about it! Zeev Zalevsky at Bar-llan University in Ramat Gan, Israel has developed bifocal glasses that make it so one can see clearly whether they are looking at something far away or close to them. Zalevsky did this by, basically, scratching the surface of an ordinary lens with "a grid of 25 near-circular structures each 2 millimetres across and containing two concentric rings" (http://www.newscientist.com/article/mg20827806.000-scratched-glasses-give-perfect-vision-for-any-eyesight.html). These scratches are just a few hundred micrometers wide and only one micrometer deep! The purpose of these scratches is to change the way light enters and passes through the lens, causing it to form a channel of light rather than a single spot of light. This is what allows the lens to work its magic. Despite this, there is apparently a decrease of contrast from the lens structure, but Zalevsky claim that the brain will adapt to this decrease in contrast by perceiving what it sees through the lens in the same way it would any regular lens. Some would say, "Don't re-invent the wheel!" but, in Zalevsky's case, a simple take on an old and long-accepted invention bore great results! Well done, good sir! The link in my post is to the better of the two articles I read, and I encourage anyone who found this interesting to read on there!