special senses- eyes Flashcards
anterior uveitis is
inflammation of the iris and ciliary body
endophthalmitis is
inflammation of the uvea and three ocular chambers
hypopyon is
accumulation of neutrophils and fibrin that settles ventrally in the anterior chamber
hyphema is
accumulation of blood in the anterior chamber
what is the ABCDE of the cornea layers
anterior epithelium
bowmans membrane
corneal stroma
descemets membrane
endothelium
true or false large animals have potentially twice the corneal layers as small animals
true, small 5-7, large 8-15
how does the cornea remain in a dehydrated state
passively through intracellular junctions and actively through solute pumps in the endothelium
how does response vary between a shallow ulceration and chronic corneal irritation
shallow- edema and a rapid return to normal by the epithelial regeneration
chronic- cutaneous metaplasia of the epithelium+ formation of rete pegs + pigmentation and fibrosis and vascularization
what is a descemetocele
a deep ulcer going down to descemets membrane
what is an indolent ulcer
failure of a normal ulcer to heal and stick to the underlying stroma
what is a melting ulcer (suppurative keratomalacia)
ulcer where release of lytic enzymes leads to stromal malacia/ necrosis
melting ulcer are usually caused by
gram negative bacteria or fungus is common cause in horses like aspergillus or fusarium (keratomycosis)
melting ulcers can be sterile however
what is keratoconjunctivitis sicca
desiccation due to reduced quantity of tear film
KCS is more common in dogs than other species- what breeds are more at risk ?
english bull dog, shih tzu, west highland terrier)
true or false- keratoconjunctivitis sicca is usually caused by bacterial pathogens
false, its a chronic, progressive and usually idiopathic disease that may be immune mediated
a french bull dog with KCS may be at risk for
ulcerative keratitis, cutaneous metalplasia and pigmentation
a dermoid can occur on the cornea or the bulbar conjunctiva, which location is most common
the bulbar conjunctiva
infectious bovine keratoconjunctivits is caused by
moraxella spp
what is the progression of pink eye
conjunctivitis and edema that progresses to central corneal ulceration and can lead to phthisis bulbi
what is the most common cause of keratitis in cats
herpesvirus keratitis (feline herpes virus 1)
true or false; FHV1 can be found on the cornea of normal healthy cats
true- this is why causality is hard to prove
dendritic ulcers are pathognomonic of what
herpesvirus keratitis
what is herpesvirus keratitis associated with and what secondary bacterial infections are likely
associated with feline sequestrums and feline eosinophilic keratitis
secondary bacterial infections include chalmydia and mycoplasma felis
what species are likely to get eosinophilic keratitis
cats and horses, cat>horses
what are the gross features of eosinophilic keratitis
in cats it starts as a raised white/ pink plaque on the lateral cornea/conjunctiva
true or false; eosinophils are the main cell type in eosinophilic keratitis
false- a chronic lesion will have more lymphocytes, plasma cells, and macrophages
what are the most common species to get a corneal sequestrum
cats>horse, dogs
what are corneal sequestrums associated with
orangne/ brown pigment in the superficial stroma
what is chronic superficial keratitis of dogs (pannus)
an immune mediated disease targeting altered antigen of the cornea - associatated with higher altitudes and UV
what are the neoplasias of the cornea
limbal melanocytic neoplasia
corneal squamaous cell carcinomas
corneal hemangiosarcoma
which speices are more likely to develop limbal melanocytic neoplasia
dogs
true or false persistent pupillary membranes are rare to find in dogs
false, pretty common
uveal cyst are common in dogs and which kind of cat
burmese cats
why is it concerning to see a uveal cyst in a golden retriever
uveal cyst are usually benign and a degenerate condition but in goldens can lead to glaucoma and pigmentary uveitis
what is phacoclastic uveitis
what happens after there’s been a ruptured lens - leads to granulomatous endophthalmitis
which fungus is associated with cataracts in rabbits
encephalitozoon cuniculi
what is moon blindness ?
equine recurrent uveitis - the most common cause of glaucoma and cataracts and blindness in horses
which bacterial infection may be associated with moon blindness
leptospira spp- the antibodies also react to components to the equine eye
what are some sequelae of uveitis
- anterior or posterior synechiae
- retinal detachment
- cataracts
- corneal vascularization
- glaucoma
- phthisis bulbi
- pre iridal fibrovascular membrane
what are the infectious causes of uveitis in cattle, cats and rabbits
cow- malignant cararrhal fever
feline- FIP
rabbit - encephalitozoon cuniculi
what are the common tumors of the uvea in cat and dog
dog- melanocytic tumors- benign mostly
cat- feline diffuse iris melanoma- malignant
true or false; diabetic cataracts are likely to affect a majority of patients and are bilateral and rapidly progressing
true; 1/2 develop cataracts within 6months 80% within 16 months
why does diabetes cause cataracts
hyperglycemia + sugar in the AQ humor, excess glucose is turned into sorbitol in the lenses, hyperosmotic effect drawing in water, the swelling leads to damage, cataracts
what is nuclear sclerosis
the cloudy blue eyes that old dogs get, its the constant adding of new lenses fibers throughout life making the lenses less transparent over time- no effect on vision
which lens luxation is painful and more likely to cause glaucoma
anterior luxation
what is the second most common primary ocular tumor in cats
feline posttraumatic ocular sarcoma
describe feline posttraumatic ocular sarcomas
initiated by ocular trauma and delayed in manifestation (5 years), arises from the lens epithelium and highly infiltrative
where does retinal detachment occur
the outer nuclear layer and the retinal pigmented epithelium
what are the 2 main mechanisms in which retinal detachment occurs
exudative detachment
tractional detachment
what species get glaucoma the most
dogs»_space;> cats»_space;»»» horses
what is glaucoma
a clinical syndrome leading to reduced aq outflow and sustained elevated IOP
what are the types of primary glaucoma
closed angle glaucoma (maldevelopment of the trabecular mesh network where the aq fluid drains) and open angle glaucoma (dysfunction of the angle rare in vet med, beagles)
what is secondary glaucoma
caused by a blockage of the iridocorneal angle by exudate or cells, or tumors hemorrhage or fibrin or inflammation or lens luxation causing the increase in pressure
what is trichiasis
hairs in a normal position are misdirected to contact the cornea - common in brachycephalic dogs- irritation
what is distichiasis
abnormally positioned eyelash coming from the opening of the meibomian glands- minor damage
what is ectopic cilia
abnormal eyelashes contacting the palpebral conjunctiva - severe corneal damage
entropion is a from of
trichiasis
what is the most common tumor of the canine eyelid
benign meibomian gland tumor
true or false eyelid melanocytomas are usually malignant
false, eyelid melanocytomas are usually benign while conjunctival melanomas are malignant
squamous cell carcinomas of the eye are most common in
cattle and horses, then cats
whats the difference in eye scc between cows and horses and cats
horses and cows it occurs on the third eyelid cats it occurs on the skin of the eyelid
