Carolina$117.00

Visual Perception Kit

Time RequiredApproximately 8 minutes per stationWith 10 stations that will require 80

minutesAdditional time is required to answer

assessment and review questions

PreparationPrior to lab review eye structure and

functionLab is designed so that 10 stations can be

set up and instructions for each station are included

Pre-lab set-upWrap white paper lengthwise around pencilsSet up “Depth Perception Tester” on level

surface

Pre-lab Activities• Demonstrate visual acuity test and benefit of

corrective lenses• Have students predict and then identify their

dominant eye– Look at an object ~3m away– With both eyes open, hold your thumb arms’

length and “cover” the object with your thumb– Close right eye– Results – if your thumb appears to move to the

right, the right eye is dominant. If your thumb did not seem to move, your left eyes dominant.

Activities Included1. Visual Acuity2. Astigmatism and Blind Spot3. Visual Mapping4. Color Vision5. Depth Perception6. Accommodation7. Near Point8. Peripheral Vision9. Afterimages10. Illusions

• Visual Acuity– Uses Snellen chart (eye chart) to determine

emmetropia (normal vision), hyperopia (farsightedness), myopia ( nearsightedness)

• Astigmatism and Blind Spot– Astigamatism- irregular shape of cornea or lens• Results in blurred or distorted images

– Blind spot- area on retina with no photoreceptors

• Visual Mapping– Used to determine the size of the fovea centralis• Fovea centralis- area of eye with greatest visual acuity,

contains more cone cells than any other region of eye

• Color Vision– Cones- cells in retina which see color– Rods- cells in retina which see dim light and shades

of gray– Different cones work together to see different

colors• Depth Perception– Ability to judge the relative distance between

objects in three dimensions– Done using monocular vision(seeing with one eye)

and binocular vision(seeing with two eyes) • Accommodation– Combination of reflex actions by which the lens of

the eye changes to keep the focal length constant– If works normally= emmetropia– If eye ball is deeper than normal = myopia– If eye ball is not deep enough= hyperopia

• Near Point– Minimum distance at which the eye can focus on

an object• Peripheral Vision– Ability to see things which fall outside the direct

line of vision– Used in the detection of motion

• Afterimages– Optical illusion that occurs when looking away

after staring intently at certain images or colors• Illusions– Deceptive, self-contradictory, or misleading

images– Visual tricks which take place in the brain rather

than the eye

Today…Get in groups of 3We will test our

Depth PerceptionPeripheral VisionIllusions