how we see Flashcards
what is the most powerful bender of light
retina
when objects are further than 6m what sort of rays reach the eye
parallel rays
when an object is close what sort of rays hit the eye
divergent- needs more bending power to focus and lens needs to become thicker
what is accomodation
changes focus from distant to close objects
what 3 things happen during accomodation
lens changes shape, pupils constrict, eyes converge
myopia
short sightedness
is myopia bending too much to too little
bending too much, biconcave lens is used
hyperopia and what lens is used to correct it?
long sightedness and convex lens
astigmatism
more than one image formed and both objects appear blurry at the same time
what sort of lens fix astigmatism
cylinder lens
presbyopia
with age your lens gets less mobile so when ciliary contract they dont change shape as well as before
where does phototransduction occur
in cones and rods
visual field
is everything you can see with one eye
what is an emmenotrope
someone with perfect vision
what is keratitis
inflammation of corneal that is infectious or non-infectious
corneal ectasia
cause cornea to thin and bulge outwards- vision gets worse over time
what symptoms do you with corneal abrasion
blurred vision, eye pain and watering.
signs of retinal detachment
squiggly lines that float across your vision, flashes of light in one or both eyes
what is coloboma
genetic eye condition when part of the tissue that makes up the eye is missing making you blind
what is glaucoma
damage to the optic nerve due to raised intraoccqular pressure leading to visual field losses
symptoms of an orbital floor fracture
orbital rim pushes the bones back and causes the bones of eye socket to buckle and damages muscles so eye can’t move properly
lesion to left optic nerve
see nothing in you left eye and normal in the right (left anopia)
lesion to optic chiasma
blindness in temporal visual fields (bitemporal hemianopia)
damage to left optic tract
right homonymous hemianopia
