{"id":1977,"date":"2012-02-16T01:26:11","date_gmt":"2012-02-16T06:26:11","guid":{"rendered":"http:\/\/eportfolios.macaulay.cuny.edu\/messenger\/?p=1977"},"modified":"2012-02-16T01:26:11","modified_gmt":"2012-02-16T06:26:11","slug":"glasses","status":"publish","type":"post","link":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/2012\/02\/16\/glasses\/","title":{"rendered":"Why Do I Need Glasses?"},"content":{"rendered":"

I\u2019ve had several conversations with a number of my friends concerning the wearing of glasses; some of them don\u2019t want to wear them because they \u201clook bad\u201d or because they don\u2019t want to look \u201cnerdy\u201d, while others think that their vision is \u201cgood enough.\u201d Regardless, the eye is a fascinating organ, and the reason for glasses is something many people don\u2019t actually understand. Personally, I like wearing glasses; they make me look smart, and my visual ego will take all the stroking it can receive.<\/p>\n

Anyway, to understand the eye, one must know about the (arguably) exciting branch of physics known as Optics. Optics deals with light\u2013its properties, behavior, etc.; since the eye is just a light sensitive organ, the two go hand in hand. The eye is actually like a camera for our brain. Light passes through a lens located at the front of the eye, and (ideally) converges the incoming light at the retina. The retina serves the same purpose as the film of a camera (or for a digital camera, a CCD chip): light hits the retina, creating a 2-D version of the world around us, which cause electrical impulses to be sent to the brain via the optic nerve. The brain interprets those impulses and creates the world that we see. With one eye, it would look just like a camera\u2019s image, with the depth being inferred by our knowledge of the world, but not actually seen visibly in the photograph. However, because we have two eyes, our brain is constantly receiving two different images at slightly different angles, and can integrate the two to create a 3-D world. Thus, people with one eye, or who cover one eye long enough time will have severe problems with depth perception (so stop blaming your bad driving on your terrible depth perception — you have no excuse!).<\/p>\n

All lenses, including those in your eye, bend light in ways depending on the shape. The lenses in your eye are convex, shaped a little like a small cigar. Convex lenses, also known as converging lenses, take incoming light and converge it at what\u2019s known as a focal point, the place where all light beams meet. It is at this focal point that a focused image is created. If you look at an object through a converging lens, unless the image screen is placed at the focal point, the picture created will be blurry. We\u2019re now approaching how you explain Myopia (nearsightedness) and Hyperopia (farsightedness). The lens of the eye has to converge light from the world onto your retina. It cannot focus the entire world at once (this is easy to notice when you focus on a far away object, and then immediately focus on, say, your hand\u2013your eye has to increase its focusing power to see your hand clearly), and so the eye adjusts the lens to allow you to focus on the image at which you are looking at. However, sometimes, it is unable to focus on either close objects (Hyperopia) or far away objects (Myopia). If the eye\u2019s lens is unable to focus the light on your retina, the images become blurry. In the case of farsightedness, you cannot focus on nearby objects, because the image converges behind your retina. So how do you correct it? You wear glasses, or \u201ccorrective lenses\u201d; these lenses are converging, and shift the focal point to your retina. <\/p>\n

\"\"<\/a><\/p>\n

So that explains farsightedness and its corrective lens solution\u2026but what about nearsightedness? Well, people with Myopia have the opposite problem — when trying to focus on far away objects, the focal point of the lens falls short of the retina, and needs to be shifted backwards. This is done using a concave or diverging lens. This type of lens is shaped like an hourglass, and causes light beams to be scattered away from each other. Then, the light beams get converged by the eye\u2019s lens, and voil\u00e0, the focal point is pushed back onto the retina. Focused images!<\/p>\n

\"\"<\/a><\/p>\n

I have (hopefully) demonstrated the cause of bad eyesight, and why glasses are a necessity for many people. Of course, contact lenses work too, it\u2019s just that they are directly on top of the eye, hence contact<\/em> lenses — the correction without sacrificing the \u201ccool.\u201d I don\u2019t know, I\u2019m a four-eyes and proud of it. So if you have bad eyesight, please get some glasses! I\u2019m looking at you, my nameless friends.<\/p>\n

This entry was originally featured on Science for Dessert<\/em>, a blog created by Dan Feldman. For more cool science, visit his site.<\/a> <\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

I\u2019ve had several conversations with a number of my friends concerning the wearing of glasses; some of them don\u2019t want to wear them because they \u201clook bad\u201d or because they don\u2019t want to look \u201cnerdy\u201d, while others think that their vision is \u201cgood enough.\u201d Regardless, the eye is a fascinating organ, and the reason for…<\/p>\n","protected":false},"author":703,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"portfolio_post_id":0,"portfolio_citation":"","portfolio_annotation":"","openlab_post_visibility":"","footnotes":""},"categories":[26],"tags":[776,896,1044,1226,1476,1598,1680,1940,2364],"class_list":["post-1977","post","type-post","status-publish","format-standard","hentry","category-science","tag-eyes","tag-glasses","tag-hyperopia","tag-lens","tag-myopia","tag-optics","tag-physics","tag-science-2","tag-vision"],"_links":{"self":[{"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/posts\/1977","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/users\/703"}],"replies":[{"embeddable":true,"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/comments?post=1977"}],"version-history":[{"count":0,"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/posts\/1977\/revisions"}],"wp:attachment":[{"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/media?parent=1977"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/categories?post=1977"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/openlab.macaulay.cuny.edu\/messenger\/wp-json\/wp\/v2\/tags?post=1977"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}