Exam 1, eyes Flashcards
What is anophthalmia
NO development of optic vesicle
- usually bilateral
- uncommon
What is micropthalmia
- miniature globe in normal sized orbit
- involution following injury to the globe (injury can be in utero, ischemic, or due to infection)
What is the difference between CYCLOPIA and SYNOPHTHALMIA
cyclopia is a SINGLE midline globe
synophthalmia has duplication of intraocular structures
What is one cause of cyclopia in sheep
ewe ingests Veratrum californicum on day 14 of gestation
What is coloboma and what is the consequence of it
- defect resulting from incomplete closure of the optic fissure
- can result in outpouching of the retina
- one of the lesions of collie eye anomaly
What is entopion
What are the secondary lesions/consequences
- inward rolling of eyelid margin due to inadequate length
- corneal irritation, ulceration
What is ectropion
What are the secondary lesions/consequences
- outward rolling of eyelid margin due to excess length
- chronic exposure keratitis, conjunctivitis (from debris collection); less severe than entropion
What is distichasis
What are the consequences
- cilia emerging from Meibomian glands (ectopic cilia)
- causes corneal and conjunctival irritation
What is trichiasis
What are the consequences
- misdirection of normal cilia such that they contact the cornea
- causes corneal and conjunctival irritation
What is chalazion
What are the consequences
- leakage of Meibomian gland
- this secretion causes granulomatous inflammation
Name one cause of conjunctivitis in cattle
bovine herpes virus I
Name one cause of conjunctivitis in cats
feline herpes virus I
Name on cause of conjunctivitis in horses
Habronemiasis (nematode larvae of Habronema deposited in conjunctiva)
What is the underlying cause of third eyelid prolapse
congenital laxity of the connective tissue anchoring the gland to the cartilage of the 3rd eyelid
What is a potential complication of surgical removal of the gland
gland produces 1/3 of aqueous tears so removal would predispose the patient to dry eye
Know the definition and potential sequela of corneal dermoid
- presence of haired skin i the corneal epithelium
- clinical significance depends on the degree of corneal irritation caused by hair
What are the 3 corneal responses to injury
adaptive cutaneous metaplasia
epithelial/stromal necrosis
wound healing/repair
Adaptive cutaneous metaplasia
- response to persistent mild irritation
- keratinization, epithelial hyperplasia, neovasularization
Epithelial/stromal necrosis
- response to more severe external injury (dessication [KCS=dry eye], mechanical injury, chemicals, infection)
- corneal ulceration secondary to edema
Wound healing/repair
- epithelium
- stroma
- sliding of cells followed by mitosis
- repaired stroma/collagen typically not transparent (granulation tissue)
What is feline corneal sequestrum
- increased superficial stromal necrosis compared to normal corneal epithelial injury
- accumulation of brown pigment from tear film (porphyrins) into corneal stroma
What is the typical morphological feature of feline corneal sequestrum
- central dark brown corneal pigmentation, is pathognomonic
What lesion is associated with pink eye
corneal ulcer that progresses to suppurative keratomalacia
What is the cause of pink eye
Moraxella bovis
- is transmitted by flies, direct contact, fomites
What is the most common cause of feline karatitis
feline herpes virus I
Know the lesion, characteristic anatomic location, and proposed cause of canine pannus keratitis
- begins at lateral limbus and spreads toward central cornea, bilateral
- is superficial stromal keratitis
- likely immune mediated disease
Know the most common cause of mycotic keratitis in horses and be able to explain the associated lesions
- Aspergillus spp. as secondary infection of corneal wound
- can progress to suppurative keratomalacia and corneal perforation due to changes in Desemet’s membrane (?)
What are the 4 lesions associated with collie eye anomoly
- choroid hypoplasia and hypopigmentation
- posterior coloboma
- retinal detachement
- microphthalmia
Hypopyon
pus in anterior chamber
Anterior uveitis (iridocyclitis)
inflammation of the iris and ciliary body
Posterior uveitis
inflammation of choroid
Chorioretinitis
inflammation of the choroid and retina
Panuveitis
inflammation of all 3 components of the uvea
Endophthalmitis
inflammation of uvea, retina, and ocular cavities (anterior/posterior chambers, vitreous)
Panophthalmia
inflammation of the entire globe, including cornea and sclera
Phacolytic uveitis
- leakage of lens protein through the lens capsule
- highly antigenic
- occurs secondary to cataracts
Phacoclastic uveitis
- release of lens protein through ruptured lens capsule –> traumatic rupture of lens capsule
- rapidly progressing diabetic cataracts
What is the most common cause of mycotic uveitis
- in dogs
- in cats
- blastomycosis (Blastomyces dermatitidis)
- cryptococcosis (Cryptococcus neoformans)
What is the typical lesion of the eye associated with mycotic uveitis
pyogranulomatous endophthalmitis (exudate accumulates in choroid and subretinal space)
Know the lesions of uveodermatologic syndrome and the predisposed breeds
- bilateral granulomatous uveitis, depigmentation of facial skin
- akitas, siberian huskies, samoyeds
What is the cause of feline infectious peritonitis
mutated enteric coronavirus
What is the lesion of FIP in the eye
immune-mediated anterior uveitis
What are the 3 proposed causes of equine recurrent uveitis (moon blindness)
- idiopathic
- immune mediated reaction against Leptospira antigen
- Onchocerca cervicalis
Name 2 uveal neoplasms of the dog, which is the most common
- uveal melanocytoma (most common)
- iridociliary adenoma
Name 2 uveal neoplasms of the cat, which is the most common
- primary ocular sarcoma (only in cats)
- diffuse iris melanoma (most common)
Name 2 neoplasms of the eyelid of dogs, which is the most common
- Meibomian adenoma (most common)
- melanocytoma
What is the most common conjunctival neoplasm in horses and cattle
squamous cell carcinoma
