Exercise 10 Flashcards
the sense of vision involves refraction of the light and focusing of light on the ____ and detection of light waves by the
retina; receptors
Cranial Nerve II
optic nerves; carry impulses from the retina to the CNS; responsible for conducting the impulse from the retina to. the optic chiasma
the nasal field of vision is projected on the ____ of the retina, and the temporal field of vision is projected on. the _____ of the retina
lateral side; medial side
Snellen chart
used to test visual acuity or the ability to focus incoming light on the retina
emmetropia
normal vision
hyperopia
farsighted; focal point of the incoming light is behind the retina bc the eyeball is too short; visual acuity is greater than 1
myopia
nearsighted; the focal point of the incoming light is in front of the retina bc the eyeball is too long; visual acuity is less than 1
Jaeger eye chart
testing for hyperopia or near visual acuity; the larger the print must be in order to read it, the less near visual acuity the person has
cornea
responsible for majority of. the refracting or bending of light rays so they fall on one spot of the retina
lens
responsible for fine-tuning the focusing of the light on the retina
astigmatism
person who has an uneven cornea; will see streaks of light radiating from the light source rather than a more uniform halo of light; use a Green’s chart
Corrective lenses
used to properly focus the light on the retina
Single vision lenses
used to correct the vision of ppl w. hyperopia or with myopia
three components of. prescription lens depending upon the vision problems of. the individual
the sphere, cylinder, and the axis component
sphere
corrects for myopia or hyperopia and is the strength of the correction measure in diopters
divergent lenses
used to. correct the vision of a person w myopia; focal point of light is moved further from the cornea and lens and corrects for the greater length of the eye; strength is negative
convergent lenses
corrects hyperopia; condenses light before it enters the eye so the focal point of light is moved closer to the cornea and lens and corrects for the shorter length of the eye; strength is positive
cylinder and axis component
cylinder - strength of the correction
axis - location. of the correction
person with astigmatism has these
optic disc
axons from the ganglion cells converge here in the retina and exit the eye. as the optic nerve; no sensory receptors (blind spot)
Amsler grid
used to detect changes. in the retina as well a in the optic nerve and the pathway of visual info in the brain
temporal field of view
allows you to see toward the lateral side of your body and provides your peripheral vision
nasal field of view
allows you to see toward and somewhat past the midlines of the body
perimeter
used to identify the field of view for each eye
accommodation
the ability to change the focal point of the eye from focusing on a. distant object to focusing on a close object; due to the contraction of the ciliary muscle and a resulting change in the shape of the lens
near point of accommodation
the shortest distance from the eye an object can be brought and still be in focus
presbyopia
the lenses lose elasticity and are less able to thicken for close vision. as a result the distance for near point of accommodation increases
to view close images
the ciliary muscle contracts, the eyes converge, and the pupils constrict
ophthalmoscope
a tool used to view the inside the eye; look to see abnormalities in the macula and fovea centrals, optic disc, and blood vessels of the eye.
