What is the stimulus for the eye?
What is visible light?
portion of electromagnetic spectrum humans can see
What protects the eye?
bony orbits of skull (cushioning fat deposits)
What are in tears to prevent infection ?
posterior four-fifths of eyeball, white connective tissue
anterior one-fifth of eye
prevent the reflection of light inside eye
what does the sclera do?
maintain shape of eye and provide site for muscle attachment
What does the cornea do?
it is the transparent and refracts light that enters the eye and bends light
What does the choroid have?
What is in the anterior chamber?
nourish lens and cornea, it is replaced everyday
opening formed by iris muscle to control opening and closing
smooth muscle regulated by ANS
What does the iris control?
amount of light entering the pupil
How does the iris gets its color?
depending on the amount of melanin pigment
what color is the eye when it has less melanin?
what color is the eye when it is rich in melanin?
Black or Brown
Iris: what is the root word for it?
Rainbow, meaning color of eye
lens of camera, transparent, adjustable
what is continuous with iris?
determining far away or close, change shape to focus, helps depth perception
What does the ciliary body control?
shape of lens
contraction of the ciliary muscles cause what to the lens?
it becomes more spherical; accommodation
what does the ciliary process produce?
what is contained in the vitreous chamber?
location through which nerves exit and blood vessels enter the eye
The blind spot is the ____ _____.
the area of the greatest sensitivity to light
where is the fovea centralis
inside the macula
The Retina is lined with what?
the photoreceptors are close to what the __________.
what is the pathway of light?
Light > cornea > anterior chamber > pupil > lens > vitreous chamber > retina
What are the layers of retina?
axons of optic nerve, ganglion cells, amacrine cell, bipolar cells, horizontal cells, photoreceptors
noncolor vision and night vision
color vision and visual acuity
how many cone types are there?
what are the three types of cones?
Blue, Red, Green
how can we see pink?
mixing the ratio of different types of cones
Most visual images are focused on the fovea centralis and macula.
The fovea centralis has a very high concentration of rods.
Macula are more cones than rods.
Where are most of the rods?
periphery of retina
Scotopic Vision uses what photoreceptor?
Photopic vision uses what kind of photoreceptors?
Peak wavelength sensitivity: Scotopic
Peak wavelength sensitivity: Photopic
Blue (cones) 420mm
Green (cones) 530mm
Red (cones) 560mm
Distinguish color: scotopic
Distinguish color: photopic
sensitivity to dim light: Scotopic
sensitivity to dim light: photopic
Location in Retina: Scotopic
primarily in the periphery
Location in Retina: Photopic
primary in the fovea
Visual Pathway: Light from each half of a visual field projects to the same side of the retina.
Visual Pathway: Left optic tract carried a complete representation of the right half of the visual field, and the opposite is true for the right optic tract.
Visual Pathway: Most axons of optic tracts synapse with neurons in the lateral geniculate nuclei LGN.
Where is the LGN ?
in the thalamus
Axons of the LGN project to the primary visual cortex in the midbrain.
Some nerve fibers in the optic tracts send branches to superior colliculi in the midbrain.
excessive pressure buildup in aqueous humor
Difficulty seeing distant objects
difficulty seeing close objects, reading
mild blockage of light to complete blindness, distortion of color vision
Difficulty seeing distant objects
regions of blindness in visual field
inability to recognize familiar faces