Study Guide Exam 2 Flashcards
Closed Angle Glaucoma
Angle-closure glaucoma, a less common form of glaucoma caused by blockage in the canals of scheme and results in a sudden rise in intraocular pressure. The blockage is the result of a closed or narrow angle between the iris and cornea.
Superior Colliculus
A layered structure, where superficial layers are sensory-related, and receive input from the eyes as well as other sensory systems, deep layers are motor-related, capable of activating eye movements as well as other responses, and there are also intermediate layers, with multi-sensory cells and motor properties.
The general function of the tectal system is to direct behavioral responses toward specific points in egocentric (“body-centered”) space.
Axial Hyperopia
A form of farsightedness where the eyeball is too short so the light doesn’t converge at the back of the eye like it should.
Optic Radiation
The axons going from the neurons in the lateral geniculate nucleus to the primary visual cortex.
Melanopsin Ganglion Cells
Cells which respond to melanopsin (a photopigment) and help regulate circadian rhythms.
Dichromat
“normal colorblindness,” they have 2/3 cones but are missing one kind
Hypercomplex Cells
Sensitive to angles, specifically the length of a particular line/angle.
Axial Myopia
A form of nearsightedness where the eyeball is extra long and so the light doesn’t hit the back of the eyeball like it should.
Decussaion vs. Commissure
Decussation: The action of crossing (as of nerve fibers) especially in the form of an X. Commissure: a band of nerve tissue connecting the hemispheres of the brain, the two sides of the spinal cord
Refractive Myopia
A form of nearsightedness where the cornea bends the light too much so it doesn’t hit the fovea
Blindsight
The ability to respond to visual stimuli without consciously perceiving them. This condition can occur after certain types of brain damage.
Visual Pathway from Retina to Visual Cortex
Retina Optic Nerve Optic Chiasm Optic Tract Lateral Geniculate Nucleus (in the Thalmus) Optic Radiation Primary Visual Cortex (V1)
Zeitgeber
Events that keep our circadian rhythms regulated. The alternation of the light/dark cycle of a 24-hour day is the most important natural zeitgeber. Another is the earth’s magnetic field. An alarm clock is an example of an artificial zeitgeber.
Deprivation Amblyopia
Also called lazy eye, its caused by visual stimulation failing to be transmitted through the optic nerve to the brain for a continuous period of time. It can also occur when the brain “turns off” the visual processing of one eye to prevent double-vision, for example in strabismus (crossed eyes). It often occurs during early childhood and results in poor or blurry vision
Vergence
The simultaneous movement of the pupils of the eyes toward or away from one another during focusing.
Contralateral Hemianopsia
Loss of vision on one side due to damage to the brain on the other side.
Object Agnosia
A form of visual agnosia in which a person cannot rely on visual cues to guide them directionally due to the inability to recognize objects. Nevertheless, they may still have an excellent capacity to describe the visual layout of the same place.
Detached Retina
The retina peels or detaches from the back of the eye. If not treated immediately, can cause blindness.
Refractive Hyperopia
A form of far sightedness where the cornea doesn’t bend the light enough.
Tectospinal Tract
A nerve pathway that coordinates head and eye movements.
Achromatopsia
Inability to see color
Cytochrome Oxidase
Found in the mitochondria, the more present in a cell, the more energy utilization happening
Decussation
The action of crossing (as of nerve fibers) especially in the form of an X.
Stereopsis
The perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision
Negative Afterimage
caused by adaptation of the photoreceptors in the retina
Hyperopia
Far Sightedness; the focal point no longer hits the fovea, its too far backward, and so everything close up is blurry.