Vision Lectures Flashcards
accommodation
focusing on far off/near objects by changing how much we bend light rays
refraction
light rays bend to form a sharp image on the retina
refractive errors
mismatch between how much we bend light
the cornea, VH, AH and lens are all transparent to allow light to fall on the ……..
retina
light waves from an object bend at the ……. bend some more at the …….. to form a clear image at the ……….
cornea
lens
retina
when the object gets closer - will the lens become thinner or thicker?
thicker
eye needs more bending power to focus on the object
the …….. is the most powerful bender of light but the …… has the capacity to change its bending power
cornea
lens
what 3 things happen simultaneously to comprise accommodation
lens changes shape (thicker and more spherical)
pupil constricts
eyes converge
myopia
short sightedness
hyperopia
long sightedness
astigmatism
non-spherical curvature of the cornea (or lens)
short sighted means distant objects are
blurred
prebyopia
long sightedness in old people
emmetrope
perfect vision
what is the most common cause of myopia?
the eyeball is too long
how do you treat myopia?
biconcave lenses
two main causes of hyperopia
eyeball is too short
cornea and lens are too flat
in hyperopia - where does the image form?
behind the retina
in myopia - where does the image form?
in front of the retina
treatment for hyperopia
biconvex lenses
astigmatism what is blurry?
both close and far away objects
how do you treat atigmatism?
cylindrical glasses (curved in only one axis)
prebyopia treatment
biconvex glasses
how do we see?
what is the process called?
phototransduction
phototransduction involves the energy in light waves stimulating …….. ………. in the retina
photoreceptor cells
phototransduction is defined as the conversion of what to what to generate what?
light energy to an electrochemical response to generate APs
phototransduced rods and cones need to activate ……. ……… ……… in order to generate an AP
optic nerve neurons
what role does vitamin A play in visual pigmentation?
visual pigment regeneration
what effects does vitamin A deficiency have?
corneal ulceration
corneal melting
amblyopia
lazy eye
pupils are different sizes. what can this be a sign of?
horners syndrome
if you see a patient with 3rd nerve palsy you must check their pupillary reflex. if absent what might this be?
cerebral artery aneurysm
horners syndrome is cause by damage to……. innervation to the eye
sympathetic
oculomotor nerve controls every eye muscle except what two?
lateral rectus
superior oblique
superior oblique is controlled by what CN?
trochlear
Lateral rectus is controlled by what CN?
abducens
when pupils are two different sizes (due to a disruption in the sympathetic innervation to the pupil) this is what syndrome?
horner’s