Function, Structure, Focus, Vision Correction The Eye Function, Structure, Focus, Vision Correction

The Ear vs. The Eye Mechanical Sound Waves with frequency range of 20-20,000 Hz Non-Mechanical Electromagnetic Waves in the Visible Light Range (4.3 x 1014 to 7.9 x 1014 Hz) Focus (pinna focuses sound waves down ear canal) Transfer (ear drum vibrates and causes the 3 tiny bones to vibrate) Interpret (cochlea resonates) Send Signals (aural nerves send impulses to the brain Focus (Cornea refracts light: initial focus through fixed convex lens) Transfer (through the pupil with 2nd refraction through lens (moveable) Interpret (light transferred to retina: cone cells color) Send Signals (optic nerve sends impulses to the brain)

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

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) Photochemical Reaction produced when frequencies of visible light are absorbed

Rods and Cones in the Retina Retina (back of eye) Rod cells (senses intensity) Cone cells (red, green and blue light receptors) Photochemical Reaction produced when frequencies of visible light are absorbed—peak at red green and blue, but produce all colors based upon intensity as well as frequency

Rods and Cones http://www.accessexcellence.org/AE/AEC/CC/vision_background.html http://webvision.med.utah.edu/photo1.html                                                                         <>   <>                                                                    <>

Colors:additive and subtractive http://mysite.verizon.net/vzeoacw1/colorsub.html http://mysite.verizon.net/vzeoacw1/coloradd.html

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 http://www.accessexcellence.org/AE/AEC/CC/vision_background.html http://webvision.med.utah.edu/photo1.html                                                                         <>   <>                                                                    <>

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

28.2 Color by Reflection This square reflects all the colors illuminating it. In sunlight, it is white. When illuminated with blue light, it is blue. This square absorbs all the colors illuminating it. In sunlight it is warmer than the white square.

Why a shirt appears blue. A blue shirt appears blue in white light because it reflects only blue and absorbs red and green (or the other colors) A blue shirt appears black in red light because it absorbs red and reflects nothing. A blue shirt appears blue in blue light because is reflects blue. A white shirt appears blue in blue light because it can reflect blue light.

Why a shirt appears blue. A blue shirt appears blue in white light because it reflects only blue and absorbs red and green (or the other colors) A blue shirt appears black in red light because it absorbs red and reflects nothing. A blue shirt appears blue in blue light because is reflects blue. A white shirt appears blue in blue light because it can reflect blue light.

Colorblindness Colorblindness is a deficiency in the number of red, green or blue cones (too few of one or more cone types). Colorblindness Normal vision http://www.toledo-bend.com/colorblind/aboutCB.html

http://www. colblindor http://www.colblindor.com/2008/10/02/color-blindness-simulator-new-tool-released-on-colblindor/

                                                           

Better Eyes http://micro.magnet.fsu.edu/primer/java/humanvision/accommodation/index.html

Rods and Cones http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/V/Vision.html

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

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

The pupil regulates the intensity of light entering the eye 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

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

Concave lens Convex lens http://www.ghi.com/yourhealth/encyclopedia/articles/color_blindness_basics.html http://micro.magnet.fsu.edu/primer/java/humanvision/accommodation/index.html

CONCAVE AND CONVEX MIRRORS Convex mirror causes light rays to converge. Concave mirror causes light rays to diverge.