Nearsightedness and Farsightedness

Manipulate[
With[{pts={{.0,0},{1,0},{.95,1},{.05,1}}},Graphics[{Thickness[.065],Orange,Line[{{.8,.55},{1,.63}}],Thickness[.025],BSplineCurve[{{.015,.3},{.215,.3},{.215,.7},{.015,.7}},SplineClosed->True],LightRed,Disk[{.5,.5},{.43,.47}],Orange,Thickness[.025],Orange,BSplineCurve[pts,SplineClosed->True,SplineKnots->"Unclamped"],LightOrange,Disk[{.09,.5},{.065,.175}],LightBlue,Disk[{.12,.5},{.04,.17}],Which[correct∧r>0,{Blue,Polygon@Join[Table[{1.01Cos[θ]+0.955336489125606-.2,1.01Sin[θ]+.5},{θ,π-.3,π+.3,.01}],Table[{1.01Cos[θ]-0.955336489125606-.2,1.01Sin[θ]+.5},{θ,-.3,+.3,.01}]]},correct∧r<0,{Blue,Polygon@Join[Table[{1.01Cos[θ]+0.955336489125606-.1,1.01Sin[θ]+.5},{θ,π-.3,π+.3,.01}],Table[{1.01Cos[θ]-0.955336489125606-.3,1.01Sin[θ]+.5},{θ,-.3,+.3,.01}]]},True,{}],Red,Thickness[.005],Line[{{-.5,.5},If[correct,{.93,.5},{1+r,.5}]}],Line[{{.12,Which[correct∧r<0,.65,correct∧r>0,.62,True,.635]},If[correct,{.93,.5},{1+r,.5}]}],Line[{{.12,Which[correct∧r<0,.35,correct∧r>0,.38,True,.365]},If[correct,{.93,.5},{1+r,.5}]}],Line[{{.12,Which[correct∧r<0,.65,correct∧r>0,.62,True,.635]},{-.2,Which[correct∧r<0,.62,correct∧r>0,.65,True,.635]},{-.5,Which[correct∧r<0,.62,correct∧r>0,.65,True,.635]}}],Line[{{.12,Which[correct∧r<0,.35,correct∧r>0,.38,True,.365]},{-.2,Which[correct∧r<0,.38,correct∧r>0,.35,True,.365]},{-.5,Which[correct∧r<0,.38,correct∧r>0,.35,True,.365]}}],Black,Point[If[correct,{.93,.5},{1+r,.5}]]},PlotRange->{{-.5,1.5},{-.1,1.1}},ImageSize->450]],
{{r,-.5,"image distance q"},-.5,.5,Appearance->"Labeled"},
{{correct,correct,"corrective lens"},{False,True}}]

CAPTION

Nearsightedness and farsightedness (also known as myopia and hyperopia) are defects of the lens, cornea, or axial dimension of the eyeball. The image of an object comes to a focus in front of the retina in one case and behind the retina in the other, causing blurred vision of distant or nearby objects. This can be corrected with concave and convex lenses, respectively, by adjusting the image distance q, which spans from the lens (light blue) to the focus (black point), to be on the retina.

DETAILS

For more details on the subject, see the Wikipedia entries Myopia and Hyperopia.

THIS NOTEBOOK IS THE SOURCE CODE FROM

"Nearsightedness and Farsightedness" from the Wolfram Demonstrations Project
 http://demonstrations.wolfram.com/NearsightednessAndFarsightedness/

Contributed by: Enrique Zeleny

A full-function Wolfram Mathematica system (Version 6 or higher) is required to edit this notebook.
GET WOLFRAM MATHEMATICA »

© Wolfram Demonstrations Project & Contributors   |   Terms of Use   |   Make a new version of this Demonstration »