This week we started to learn about sensation and perception. The first sense that we learned about is vision. As we learned about the eye itself, Mrs. Perl mentioned the lens, the part of the eye that bends different ways to make the picture you are seeing clear. The lenses bend the lightwaves that are entering the eye which allows us to see the picture clearly. If your lenses don't bend correctly, you can't see clearly. Glasses act as an external lens. Even though glasses don't physically bend, like your internal lenses, the lenses of the glasses are bent and curved correctly to see the lightwaves clearly.
When people have trouble seeing, they are either nearsighted, or farsighted. When someone can see perfectly, the lightwaves entering the eye focus directly on the retina rather than in front of or behind. People who are nearsighted, the lightwaves entering their eyes are focuses right in front of the retina and people who are farsighted, the lightwaves focus behind the retina.
The lenses in glasses are bent and curved differently for nearsighted and farsighted people. For nearsighted people, the lenses are curved in which bends the light towards the top of the lens causing the focal point in the eye to move closer to the retina. For farsighted people, the lenses are bent in a concave fashion which helps the light bend more to the center of the lens causing the focal point to move forward.
I hope that this blog post has helped my glasses-wearing friends understand the function of glasses and that they aren't just for fashion (even though spongebob simply rocks the ray-bands).
Thanks for the information about glasses! I have been wearing glasses for nine years now and I didn't known exactly why until we covered sensation and perception of vision in class. For the past five years, I have also been wearing contact lenses. Although you didn't mention it in your post, I find it very interesting that I wear my contacts for up to fourteen hours a day and that I don't feel them. This is sensory adaptation at work. Since my brain can only process 40 bits of information a minute, it puts the sensation of annoying circles over the cornea to the side while it processes other information. In Twilight (I know, bad reference) the vampires sometimes wear contact lenses to mask their garish red eye color. Vampires innately have extremely low absolute thresholds and superhuman cognitive skills, so the contact lenses over their eyes do bother them more than they bother a human. This is all just food for thought about the science behind wearing corrective lenses.
ReplyDeleteHave you ever thought about how cool contact lenses are? You're basically inserting an artificial lens into your eye and wearing it around all day. Major props to whoever invented contact lenses. They really make life so much easier (though I do love my glasses of courses.)
ReplyDeleteResponding to Lily, I never actually did think about contact lenses. But I guess the name would suit itself. It truly is like a lens you are putting into your eye to fix your vision. Never thought of it like that! Thanks for the insight
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