Vision Flashcards
scotopic vision –
monochromatic vision produced through the rods in low light
photopic vision
– chromatic vision produced through the cones under well-lit conditions
dark current
– continuous inflow of Na+ and Ca++ into rods and cones in dark through cGMP-regulated channels, causing hypopolarization and glutamate release
hemidecussation
– partial crossing of optic fibers in the chiasma opticum ensuring that information collected from the same part of the visual field by the two retinas is analyzed in the same hemisphere
Optic illusion
is characterized by visually perceived images that differ from objective reality.
sclera
– the outermost, white layer of the eyeball
cornea
– frontal, transparent part of the sclera with the highest refracting power
conjunctiva
– very sensitive epithelial membrane covering the sclera and cornea and lining the inside of the eyelids
iris –
circular, pigmented membrane behind the cornea, perforated by the pupil; its contraction regulates the amount of light passing into the eye
choroid
– the middle, vascularized layer of the eyeball, including the iris and the ciliary body (ciliary muscles)
fovea centralis
– a depression in the center of the macula of the retina, the area of the most acute vision, where only cones are present
blind spot (optic disc)–
the spot on the retina, where the axons of the ganglion cells and blood vessels penetrate the wall of the eyeball; no receptor cells are found here
musculus ciliaris
– the lens is attached to the ciliary body (ciliary muscles) in the eye, its contraction is needed for accommodation
glaucoma
– eye disease caused by an excessive intraocular pressure due to a disturbance in the production and reabsorption of the aqueous humor
cataract –
eye disease caused by an opacity of the lens