The Visual System Flashcards
Name the major components of the human eye
- Cornea
- Iris
- Pupil
- Lens
- Retina
The _________ is the transparent protective tissue located over the front of the eye
Cornea
Iris
Round pigmented membrane that adjusts the amount of lights that enters the eye
The _______ is the opening in the center of the iris. It allowa light to enter the eye.
Pupil
The _______ is a transparent, biconvex membrane that directs light rays entering the pupil upon the retina.
Lens
Retina
Thin multi-layered membrane which covers most of the posterior compartment of the eye, contains the photoreceptors
What two types of photoreceptor cells are located in the retina?
Cones and Rods
Where are Cones located within the retina
Located in Fovea Centralis and parafovea region
What are the functions/qualities of Cone cells?
Respond selectively to colors, sharp detals, allows for daytime vision.
Where are Rods located within the retina
Located in peripheral region and parafovea region
What are the functions/qualities of Rod cells?
very sensitive to low light levels, allows for night vision, poor acuity; detects movement, and edges/lines. Not color sensitive, shades of gray/”purple”
Where is the day blind spot and how many degrees does it cover?
Located in the optic disk because it contains no receptor cells (also blind at night).
Covers 5.5 to 7.5 degrees
Where is the Night blind spot and how many degrees does it cover?
Located in the Fovea Centralis area because it contains no Rods.
Covers 5 to 10 degrees of the field of vision.
Astigmatism
Unequal curvature or irregularities in the cornea or lens that create multiple focal points in the anterior chamber
Myopia
nearsightedness; far objects are blurry
Hyperopia
farsightedness; near objects are blurry
Presbyopia
“old eyes”; due to hardening of the lens that occurs naturally with age; both near and far objects appear blurry; need bi-focals
Types of approved corrective eye surgery
PRK, LASIK, and LASEK
Types of vision
P.M.S. Photopic Mesopic Scotopic
Photopic
Day vision
Mesopic
Dusk/dawn; full moon, twilight vision
Scotopic
Night vision; partial moon or starlight
Which type of vision is considered the most dangerous for Aviation
Mesopic
Cues to distance estimation and depth perception (2 types)
Binocular and Monocular
Monocular
Visual cues from one eye
Binocular
Visual cues from two eyes
Which type of cue is more important in aviation (monocular or binocular)
Monocular
What is the acronym for the monocular cues for depth perception
G.R.A.M.
Expand the acronym G.R.A.M
Geometric Perspective Retinal image size Aerial perspective Motion Parallax
Types of Geometric Perspective L.A.V.
Linear Perspective Apparent Foreshortening Vertical position in the field
Types of Retinal image size K.I.T.O.
Known size of objects Increasing or decreasing size of objects Terrestrial association Overlapping Contours
Types of Aerial Perspective F.L.P.
Fading of colors and shades Loss of textures and detail Position of light source
What is the MOst important of the MOnocular cues
MOtion parallax
_______ compensates for the night blind spot?
Scanning
An unequal curvature of the cornea resulting in the inability of the eye to focus on multiple objects simultaneously in the horizontal and vertical planes is called?
Astigmatism
What is the proper name for nearsightedness?
Myopia
What is the proper name for farsigthedness?
Hyperopia
This occurs with the aging process and results in the hardening of the lens?
Presbyopia
Vitamin A is required for the production of?
Rhodopsin
The apparent relativ motion of stationary objects as viewed by a moving observer is?
Motion Parralax
Average time to dark adapt is ____ - _____ minutes for a well rested aviator
35 - 40
