Special Senses: Vision
Define PRESBYOPIA
"OLD VISION" - Lengthening of the near point accommodation
A test result of 20/15 is better or worse than normal vision
20/15 VISION IS BETTER than normal
Define CATARACTS
A condition causing the lens to become increasingly hard and opaque
Define ACCOMMODATION
Ability of the eye to focus on objects closer than 20 ft
The ability of the eye to focus differently for objects of near vision & 6m (20 feet) is called?
Accommodation
______ is blurred vision caused by irregularities in the curvature of the lens or cornea
Astigmatism
The ______ chart was used in the lab to show irregularities in curvature of the lens/cornea
Astigmatism chart
Predators have what type of vision?
Binocular vision/depth perception
Name one part of the fibrous tunic/layer labeled "A" with the blue tape
Cornea/Sclera
Define HYPEROPIA
Farsightedness. Image is focused behind the retina
name one depolarizing cell found in the sensory layer/tunic
Ganglion cell, bipolar cell, rods, or cones
What is the cause of presbyopia?
Loss of elasticity of the lens over time
Fibers from which eye are found in the left optic tract?
Medial fibers from right eye and laterals fiber from left eye
closer in children and young adults and farther with old age, the _______ is the closest distance an object can be focused on clearly
Near point of accommodation
Define MYOPIA
Nearsightedness. Image is focused in front of retina
the ______ chart is used to measure visual acuity
Snellen Chart
The Snellen chart was used to test _____
Visual acuity
The branched optic radiations will terminate in which region of the brain?
Visual cortex
what do the tarsal glands produce?
an oily substance
name one part of the vascular tunic/layer labeled "A" with the blue tape
choroid
the _____ lens is used to correct the myopic/nearsighted eye
concave
which specific type of lens is used to correct myopia?
concave lens
the photoreceptor cells called _____ are responsible for color vision
cones
what is the medial rotation of the eyes called?
convergence
The _____ lens is used to correct the hyperopic/farsighted eye
convex
Which specific type of lens is used to correct hyperopia?
convex lens
what are the tears comprised of?
dilute salt solution with lysozymes
What is the function of the ciliary glands?
eyeball lubrication
What do the extrinsic muscles allow the eye to do?
eyeball movement, follow a moving object
what is the function of the lacrimal sac?
fills & stores tears
What eye disorder is caused by compression of retina/optic nerve?
glaucoma
Name one of the non-depolarizing supporting cells found in the retina
horizontal cells
What is a sty?
inflammation of the ciliary (sweat) glands or a small oil gland
what is conjunctivitis?
inflammation of the conjunctiva
Name one of the 2 groups of muscles responsible for eye reflexes
intrinsic/extrinsic muscles
What is the function of the lysozyme?
kill bacteria
Name of constituent of the lacrimal apparatus
lacrimal sac
Fibers from which eye are found in the left optic nerve?
left eye
Fibers from which eye are found in the optic chiasma
median fibers from the left and right eyes
prey tend to have what type of vision?
panoramic
the _____ reflex is observed by sudden illumination of the retina by bright light causing the pupil to constrict in direct proportion to light intensity
photopupillary
what is the function of the scleral venous sinus?
reabsorption of aqueous humor
what accompanies conjunctivitis in the eyeball?
redness
what is the bending of light upon passing from one substance to another called?
refraction
light bending power of the cornea, lens, or vitreous humor is called its
refractive index
in the convergence reflex test done in the lab, what was the reaction of looking and focusing at a distant object and then focusing at a very close object by the eyes?
regular eye movement, then medial eye movement to view close object
The ____ is the part of the eye that is examined when using the opthalmascope
retina
name one part of the sensory tunic/layer labeled A with the blue tape
retina
fibers from which eye is found in the right optic nerve?
right eye
the photoreceptor cells called _____ are responsible for dim light vision
rods
what do the lacrimal glands produce?
tears
A test result of 20/40 is better or worse than normal vision
worse than normal vision
______ is the general name of the involuntary muscles that are responsible for changes in both the lens curvature and pupillary size
Intrinsic muscles
_______ is the specific name of the color plates used to test for color blindness in lab
Ishihara Color Plates
optic tract fibers will synapse with what part of the brain?
Lateral geniculate body of the thalamus
What causes glaucoma
Optic nerve due to lack of drainage of the aqueous fluid
fibers/axons from the lateral geniculate nucleus will branch into the
Optic radiation
In the accommodation pupillary reflex test done in the lab, what was the reaction of looking and focusing at a distant object and then focusing at a very close object by the pupils?
Pupil dilation & constriction
