Vision Flashcards
What is the function of the pigmented layer of the retina and what is the pigment?
Melanin
Nutrition
Ensures no reflection back to the retina
What are they 3 classes of visual neurones?
Ganglion
Interneurones
Photoreceptors so rods and cones
What is retinal detachment?
The neural and pigmented layer separate and therefore the photoreceptors may not recieve the nutrition they need
Which layer of the retina are the rods and cones in?
Outer neural layer
What cells does the inner nuclear layer of the retina contain?
Amacrine cells
Horizontal cells
Bipolar cells
What is the function of the ganglion cells?
Responsible for the final output from the retina after it has been to the CNS
What are cones responsible for?
Daytime vision
Colour
What are rods responsible for and where are they not found?
Night vision
Not found in the central retina
What colour vision do we have?
Red, blue and green
How is a colour formed as vision?
Colours arms mixed depending on the cones that are stimulated and also depends on frequency of impulses
What artery supplies the central retina?
The central artery of the retina
What artery supplies the choroid, rods and cones?
The ciliary artery
Where does the upper retinal field tracts go around?
Parietal lobe
Where does the lower retinal field fibres run around?
Temporal lobe
What are the 4 events that happen with accommodation?
Lens bulges
Convergence of eyes
Contraction of ciliary muscles
Pupils constrict
What is lateral strabismus?
The eyes are not both coordinated
One faces outwards
What is ptosis?
Dropped eyelid
What are saccadic movements?
Fast, horizontal movements
What is exotropia?
Eye turned out strabismus
What is esotropia?
Eye turned in strabismus
What is hypertopia?
Eye is elevated strabismus
What is hypotopia?
Eye depressed strabismus
What visual field defect do you get with gluacoma?
You get a peripheral visual field defect which only becomes apparent when the fovea is damaged
Why can you sometimes get a defect affecting the macula but still have macula sparing?
Large amount of receptors and a large representation in the brain
What is horners syndrome?
Sympathetic lesion
Anhydrosis on side of lesion
Ptosis
Miosis
What eye defect do you get with albinism?
Nystagmus
What is hypermetropia?
Far sightedness
Due to eyeball being top small or lens is too weak resulting in bending of light
What is myopia?
Near sightedness
Either eye is too elongated or there is increased power of the lens
What cones are affected in colour blindness?
Red and green
What is retinitis pigmentosa?
Gradual loss of vision
Degeneration of photoreceptors
Apoptosis
Narrowed retinal vessels and formation of clumps near blood vessels
