Intro | Cornea | Optic Disk and Blind Spot | Fovea | Iris | Lens | Muscles (to move eye) | Muscles (to adjust lens) | Optic Nerve | Pupil | Retina

Part 1: Image-Mapped Tutorial
Part 2: Matching Self-Test
Part 3: Multiple-Choice Self-Test

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The Lens of the eye lies directly behind the cornea, and acts to focus the light rays on the receptor cells of the retina. As in a camera, the lens of the eye inverts and reverses the image of the outside world on the retina. Light from the left side of the world will hit the right side of the retina and light from above will hit the bottom of the retina (see for example the inverted pencil in the figure). Sometimes the lens becomes cloudy with increasing age. These so-called cataracts affect approximately 3/4ths of people over the age of 65.