How do glasses help us see? - Andrew Bastawrous and Clare Gilbert
View full lesson: http://ed.ted.com/lessons/how-do-glasses-help-us-see-andrew-bastawrous-and-clare-gilbert Today, glasses help millions of people with poor ...
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Almost 2000 years ago, the Roman philosopher Seneca peered at his book through a glass of water. Suddenly, the text below was transformed. The words magically became clear. But it wasn't until a millennium later that that same principle would be used to create the earliest glasses. Today, glasses can help millions of people with poor vision due to uncorrected refractive errors. The key to understanding what that means lies with the term refraction, the ability of a transparent medium, like glass, water, or the eye to change the direction of light passing through it. The eye has two main refractive surfaces: the cornea and the lens. Ideally, these surfaces work together to refract light in a way that accurately focuses light onto the retina, the layer of light-sensitive tissue a...
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Almost 2000 years ago, the Roman philosopher Seneca peered at his book through a glass of water. Suddenly, the text below was transformed. The words magically became clear. But it wasn't until a millennium later that that same principle would be used to create the earliest glasses. Today, glasses can help millions of people with poor vision due to uncorrected refractive errors. The key to understanding what that means lies with the term refraction, the ability of a transparent medium, like glass, water, or the eye to change the direction of light passing through it. The eye has two main refractive surfaces: the cornea and the lens. Ideally, these surfaces work together to refract light in a way that accurately focuses light onto the retina, the layer of light-sensitive tissue a...
