Special Senses
What are the characteristics of collie eye anomaly?
-Choroidal hypoplasia -Optic disc coloboma (defect) -Retinal detachment + rosettes.
What are four defects that affect the organogenesis of the entire eye?
1. Anophthalmia- No globe development. 2. Microphthalmia- Inadequare growth > small/disorganized globe 3. Cyclopia/ Synophthalmia - Single globe vs. incomplete separation of globes. 4. Coloboma - Congenital absence/defect of tissue resulting in a "gap".
What infectious agent causes "blue eye"? What layer of the cornea does this target?
Canine adenovirus-1. Targets corneal endothelium (bottom layer of cornea). Destroys ion channels so dehydration quickly occurs.
Compare and contrast the disease presentation of Chlamydophila felis and Feline herpesvirus-1.
Chlamydophilia felis- Bacterial conjunctivitis. Feline herpesvirus-1- Viral conjunctivitis.
White in the cornea indicates
Fibrosis (mild, chronic dz or an eye that has healed)
Compare and contrast Infectious Bovine Rhinotrachetitis and Infectious Bovine Keratoconjunctivitis.
Infectious Bovine Rhinotrachetitis- Viral conjunctivitis caused by bovine herpesvirus type-1. Purulent conjunctivitis & respiratory dz. Not pinkeye. Infectious Bovine Keratoconjunctivitis- True pinkeye. Transmitted by face fly (muscus autumnalis), caused by Moraxella bovis (a cytotoxin). Lacrimation, blepharospasm, corneal ulceration.
What ocular defect arises from incomplete atrophy of the fibrovascular sheet?
Persistant pupillary membrane
What layer of the cornea is dehydrate? Why does this matter in corneal ulcers?
Stroma = dehydrate Corneal ulcers cause injury to the epithelium and stroma. This allows fluid in > edema > blindness.
What parasite is a "true" eye worm (one that inhabits the conjunctival sac)?
Thelazia
What plant causes cyclopia/synophthalmia in lambs? What day of gestation do gravid ewes have to ingest this plant for this to occur?
Veratrum Californicum. Day 14 of gestation.
Red in the cornea indicates
blood vessels
Yellow in the cornea indicates
cellular infiltrates
Blue in the cornea indicates
corneal edema
Brown in the cornea indicates
pigment
Black in the cornea indicates
sequestrum or foreign body