Uvea Flashcards
What are PPMs?
Incomplete absorption of embryonic vascular tissue and mesenchymal tissue
Originate from the iris collarette
What is the iris collarette?
Separates ciliary zone from pupillary zone
What does the uvea do?
Aqueous production
Maintenance of blood-ocular barrier
Light regulation
Accommodation
What are the two components of the blood ocular barrier?
Blood aqueous barrier
Blood retinal barrier
What does the disruption of the blood ocular barrier cause?
Uveitis
What are the components of uveitis?
Inflammation of the uvea
Increased blood supply
Augmented vessel permeability
White blood cell migration
Breakdown of the blood ocular barrier
What are the clinical signs of uveitits?
Blepharospasm
Epiphora
Photophobia
Red eye - ciliary flush, episcleral injection
Corneal edema
Miosis - charley horse of the eye, contraction of muscles
Aqueous flare
Hyphema
Hypopyon - WBC in the anterior chamber, sinks to the bottom of the eye
Fibrin - mainly cats and horses
Keratic precipitates
Swollen/thickened iris
Iris hyperemia
Rubeosis iridis (chronic)
Decreased intraocular pressure
What are the main chronic clinical signs of uveitis?
Posterior synechia
Iris hyperpigmentation (prostaglandin)
Cataract
Secondary lens luxation
Secondary glaucoma
Retinal detachment
Phthisis bulbi
What is the most common type of uveitis?
Endogenous - comes from inside the eye or bloodstream
What would you see with disseminated mycotic infections?
Pyogranulomatous inflammation
Often involves posterior segment
What would you see with intraocular nematodiasis?
Identification of parasite
Migratory tracts in retina
What would you see with rickettsial diseases?
Vasculitis and retinal hemorrhage
Especially with Ehrlichia
What would you see with lens-induced uveitis?
Leakage of lens proteins from a cataract
Very common
Suspect in any red eye with a cataract
Results from exposure of immunologically isolated lens protein to the immune system
What would you see with uveodermatologic syndrome?
Autoimmune disease directed against melanocytes
Severe bilateral panuveitis
Depigmentation of iris and/or choroid
Ulceration and vitiligo of facial mucocutaneous junctions
Akitas
What would you see with hyperlipidemia?
Elevation of either cholesterol or triglycerides
Milky white lipid laden aqueous