Lecture 9: Equine Ophthalmology Flashcards
Horses visual field is __degrees
350
Retina contains rods and cones in a __ ratio
9:1
rods sensitive to __light and ___
dim light, motion detection (night vision)
cones sensitive to ___, responsible for __vision
bright light, color vision
what colors do horses see
blue, green, yellow
define Epiphora
tearing (pain)
define blepharospasm
squinting (pain)
foals less than __weeks do not have menace
2-3 weeks
what CN do PLR test
2 and 3
what CN do you test for palpebral reflex
5 and 7
what CN do you test with menace
2 and 7
what CN do you test with dazzle
2,3, and 7
Identify 1-3
- Tapetum
- Non-tapetum
- Optic disk
what are the black dots that arrow pointing to
stars of Winslow
what IV sedation used for eye exam and what dose
xylazine at 150-250mg for 1000lb horse
what blocks are used on eye and what do they block
auriculopalpebral- motor to orbicularis oculi
Supraorbital nerve- sensory to medial 2/3 upper eyelid
Identify blocks 1-2
- Auriculopalpebral
- Supraorbital
what diagnostic test do you do on every horse, every time with eye problem
fluorescence stain
fluorescein stain adheres to __
corneal abrasions
Schirmer tear test must be done prior to ___ and ___
any medications in the eye, prior to sedation with alpha-2 that increase lacrimation
when is the schirmer tear test indicated
Chronic ulcerations or dry cornea
<__mm on schirmer tear test is deficient
10
what is normal IOP
16-30mmHg
consistently high IOP indicates __
glaucoma