Eyes Flashcards
Eye development in children
- macula develops 4-8 months- 80% NB farsighted (decreases 7-8yrs)- eyeball adult size age 8
Eye Developments in Older Adults
- drooping (loss of skin elasticity)- lipids gather at iris/limbus- lens cannot change shape (presbyopia), discolors/thickens (cataract)- floaters in vitreous humor- glaucoma (increased pressure)
distance vision acuity test
Snellen Chart- patient at 20 ft- 20/20 (distance/where normal eye could read same line)- 20/200 = legally blind
myopia
nearsighted
hyperopia
farsighted
presbyopia
> 40; trouble reading due to loss of ability of lens to accommodate (not shape of eye)
approximate completely
when upper lid and bottom lid close completely
Pupil size
3-5mm 5 mydriasis (increase intraocular pressure - glaucoma, increase intracranial pressure)
strabismus
weakness or paralysis of 1+ extraocular muscles, due to congenital defect, orbital fracture, trauma, or CVA-related palsy
nystagmus
when eyes will oscillate in place, only normal in far lateral view
visual pathways: optic nerve cut
blind in that eye, CN2 does not cross over
visual pathways: chiasm cut
bitemporal hemianopsia: blind in temporal vision field; only the fiber on the nasal side crosses over chiasm (nasal views temporal)
visual pathways: optic tract
will lose nasal field in side that was affected and temporal field of opposite side
optic disc
fibers converge to form CN2; on nasal side, should have distinct edges; creamy yellow/pink in color
physiologic cup
small circle area inside disc - where blood vessels exit and enter