The Eye Function, Structure, Focus, Vision Correction

Stare at bird for 30 s and look to left—what color is the ghost image?

Cyan (blue light + green light) Your red cone receptors are fatigued, so you only perceive cyan.

The Eye and its Structure Focusing lenses (double convex lens system) –Cornea (convex lens)--main focusing, fixed –Lens (convex lens)—fine focusing, adjusts Pupil (light regulator) Retina (back of eye) –Rod cells (senses intensity) –Cone cells (red, green and blue light receptors)

Rods and Cones in the Retina Retina (back of eye) –Rod cells (senses intensity) –Cone cells (red, green and blue light receptors

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Colorblindness Colorblindness is a deficiency in the number of red, green or blue cones (too few of one or more cone types). Normal vision Colorblindness

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What is color? When we see color, we are seeing specific frequencies of visible light VISIBLE LIGHT IS ROYGBIV Red, orange, yellow, green, blue, indigo and violet For visible light –Red has the lowest frequency and longest wavelength –Violet has the highest frequency and shortest wavelength

When sunlight passes through a prism, it separates into a spectrum of all the colors of the rainbow The Color Spectrum roygbiv

Both the cornea and inner lens are convex (convergent) lenses The retina contains rod and cone cells that are photosensitive to different frequencies of visible light. Red-green- blue cone cells are the color receptors The pupil regulates the intensity of light entering the eye

30.6 The Eye Inner lens moves to focus close up and far away images

Concave lens Convex lens

Vision correction Corrected by divergent (concave) lens Corrected by convergent (convex) lens

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Colorblindness Colorblindness is a deficiency in the number of red, green or blue cones (too few of one or more cone types). Normal vision Colorblindness

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