The Retina Flashcards
What are some questions importantly asked when history-taking in an ocular exam?
- breed & age
- Why might the other eye have been removed?
- which/where was change noted in eye?
- one or both eyes? local or systemic cause? general health status?
- constant/intermittent?
- Vision loss slow or sudden?
- vision worse day or night? does it go out at night?
- on any txt?
Ocular exam
- basic eye reflexes - direct, consensual, menace, dazzle
- complete exam of eye & adnexa
- fundic exam
What is important to remember when evaluating menace reflexes?
be careful not to create air mvmt or touch face –> gives false positive
Direct reflex causes
pupillary constriction in an illuminated eye
Consensual reflex
pupillary rxn in a non-illuminated eye
Dazzle reflex does not affect the…
visual cortex not involved (subcortical solely)
Facts of menace responses
- some animals are stoic & will not react
- neonates have poor reflex dvlpmt until 10-12 wks in foals, pups, kittens
- may be present w/ adv’d retinal dz
- need to test all quadrants of the fundus b/c retinal lesion can be focal
Lack or presence of reflexes does not =
Vision
PLR present + no vision =
Add examples if possible
dz of optic radiation, lateral geniculate, body & visual cortex
Ex: anoxia, polioencephalomalacia, storage dz, hydrocephalus, neoplasia, distemper, GME
No PLR + vision present =
Add examples
eye dz
Ex: ** synechia, atropine, uveitis, iris atrophy, fright**, ciliary ganglion paralysis (Addies syndrome)
PLR + Adv’d retinal dz requires use of
darkened room, good focal light source
mature cataracts do not affect
PLR
iris dz will affect
PLR
Eye reflex + adv’d retinal dz due to… prevent by…
Due to melanopsin ganglia (3% of ganglia)
Prevent by using red light stimulation for rods/cones, blue light for melanopsin
condition?
iris atrophy
Irregular iris margin, scalloped appearance
older poodles, yorkies, possibly any breed
