Vision Flashcards
How do cone cells work?
Cone cells use iodopsin to respond to visual stimulation. Each cone cell is connected to a single nerve and sends sharp, colored images to the brain under good light and fuzzy, black and white images to the brain under dim light. (8-7)
How do rod cells work?
Rod cells use rhodopsin to respond to visual stimulation. From 10 to 10,000 rod cells are connected to each nerve; resulting in greater light sensitivity but lower acuity. Rod cells see only shades of grey. (8-8)
How long does full dark adaptation take?
30 to 45 minutes. (8-10)
How large is the day blind spot?
5.5 to 7.5 degrees — located about 15 degrees from the fovea. (8-11)
What are the three types of vision and when are they active?
- Photopic — daylight (8-13)
- Mesopic — dawn, dusk, and moonlight (most dangerous) (8-14)
- Scotopic — dark/low light (8-15)
How large is the night blind spot?
5 to 10 degrees in the center of the visual field. (8-16)
What are the primary visual deficiencies?
- Myopia — nearsightedness (8-19)
- Hyperopia — farsightedness (8-22)
- Astigmatism — difused images (8-23)
- Presbyopia — lens hardening (8-24)
- Retinal Rivalry — conflict between aided and unaided eye (8-26)
What are the night vision techniques?
- Off-Center Vision (8-47)
- Scanning (8-50)
- Shapes or Silhouettes (8-52)
What are the categories of monocular cues?
- GRAM
- Geometric Perspective (LAV)
- Retinal Image Size (KITO)
- Aerial Perspective (FLiP)
- Motion Parallax *
(8-55)
What are the geometric perspective monocular cues?
- LAV (8-56)
- Linear Perspective
- Apparent Foreshortening
- Vertical Position in Field
What are the retinal image size monocular cues?
- KITO (8-60)
- Known Size of Objects
- Increasing or Decreasing Size of Objects
- Terrestrial Association
- Overlapping Contours
What are the aerial perspective monocular cues?
- FLiP (8-65)
- Fading of Colors or Shades
- Loss of Detail or Texture
- Position of Light Source and Direction of Shadow
