Vision and Eye movements Flashcards
what is the coloured part of the eye?
the lens
what eye structure receives light from the lens?
the retina
what is analogous to the skin?
the retina
where are photoreceptors within the eye located?
in the peripheral retina
what are photoreceptors analogous to?
mechanoreceptors in the skin
what do photoreceptors respond to?
a change in light
what are the types of photoreceptors?
rods and cones
where are rods primarily found?
the peripheral part of the retina
what does it mean that rods are achromatic?
the don’t sense colour
what helps us to see in low levels of light?
rods
are there more rods or cones?
rods! 20:1 ratio
where are cones found in the retina?
centre of the retina (fovea)
what lets us see colour?
cones
what is the region of the retina where axons are leaving?
optic disk
where in the eye are there no photoreceptors?
in the optic disk (blind spot)
is the blind spot the same in both eyes?
no
where does most of our vision come from?
macula
what eye structure is responsible for detailed vision?
fovea
where does all the high acuity vision occur?
in the center of the retina
what are the 2 types of ganglia in the ganglion cell layer of the eye?
parasol ganglion cells
midget ganglion cells
what are characteristics of parasol ganglion cells?
large cell bodies, receptive fields, axons
what are the characteristics of the midget ganglion cells?
small cell bodies, receptive fields, axons
fine visual detail and colour
more numerous
what demographic often has macular degeneration?
people with diabetes
older individuals
what eye structure is impacted with macular degeneration?
macula
what does macular degeneration look like?
central vision affected
what causes diabetic retinopathy?
excess blood sugar damages retinal blood vessels
what does diabetic retinopathy look like?
patty vision loss throughout the visual field
what is cataracts?
blurring of the lens or a clear coating over the eye