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82 Cards in this Set
- Front
- Back
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What 3 structures normally atrophy around birth?
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hyaloid artery
pupillary membrane tissue covering iridocorneal angle |
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What are 2 conditions of defective organogenesis of the eye?
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microphthalmia: congenitally small eye (horses, cattle)
coloboma: a notch-like defect resulting from incomplete fusion of lips of embryonic fissure |
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What is persistent pupillary membrane?
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failure of pupillary membrane to atrophy around time of birth
iris strands go to lens very common & usually subclinical heritable in Basenji, Collies, Corgis; spontaneous in most dogs |
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What is goniodysgenesis?
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maldevelopment of iridocorneal angle
can lead to 2º glaucoma |
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What are some conditions resulting from anomalies of surface ectoderm?
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dermoid: piece of skin (often haired) stuck to cornea or conjunctiva (choristoma)
microphakia, lenticonus, lentiglobus: shape & size abnormalities of lens congenital cataract |
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macropalepbral fissure
a. signalment b. predisposes to.. c. concurrent facial features d. tx |
a. familiar trait in brachycephalic breeds
b. lagophthalmos (inability to completely close eyelids) & corneal ulceration c. shallow orbits, large eyelid openings, nasal fold hair that can rub on surface of eye d. medial canthoplasty |
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disthichiasis
a. definition b. predisposes to.. c. tx |
a. cilia emerging from a dysplastic gland, usually meibomian gland
b. cause corneal & conjunctival irritation/ulceration if they contact globe (often asymptomatic) c. cryosurgery |
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entropion*
a. definition b. signalment c. predisposes to.. |
a. inversion of lid margin & periocular skin
b. -1º entropion seen in breeds w/ excess facial skin (ex. Shar Pei) -common in newborn sheep, horses d/t tissue edema (transient) c. contact of facial hair w/ globe --> conjunctival & corneal irritation |
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meibomitis (internal Hordeolum)*
a. defintion b. species affected c. etiology |
a. suppurative inflammation of meibomian glands
b. dogs, cats. c. usually d/t Staph infection & often assoc. w/ generalized dermatoses |
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chalazion*
a. definition b. gross appearance c. cause |
a. granulomatous inflammatory rxn to retained meibomian gland secretions
b. firm, yellow mass visible thru palpebral conjunctiva c. obstruction of glands d/t adenoma or inflammation |
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blepharitis
a. defintion b. etiologies |
a. inflammation of eyelid skin
b. Staph (dogs), pox virus (birds), dermatophytes, Demodex (dogs), Habronema (horses), allergic or immune mediated (ocular manifestation of atopy) |
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meiobomian gland adenoma*
a. signalment b. biolgic behavior c. tx |
a. very common in older dogs
b. benign, slow growing c. cryosurgery preferred (will recur w/ excision) |
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eyelid melanoma*
a. species affected b. biologic behavior |
a. dog
b. benign |
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What is the biologic behavior of eyelid SCC in cat?*
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malignant: usually fast growing & locally invasive, but not metastatic
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What are the responses to injury of conjunctiva?*
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hyperemia
chemosis (edema) ocular discharge (serous, mucoid, purulent) follicle formation (lymphoid tissue: nonspecific finding assoc. w/ chronic irritation) |
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conjunctivitis*
a. etiology in dogs b. etiology in horses c. etiology in cats |
a. often secondary to other ocular dz
bacteria (bacteria found in conjunctival sac of normal eyes --> conjunctivitis occurs when an injury alters normal homeostasis & allows bacteria to proliferate), allergic, systemic viral dz (distemper), rickettsial b. often secondary to other ocular dz bacterial, allergic, parasitic (Habronema, Onchocerca) c. usually d/t primary pathogen feline herpes virus-1, Chlamydia felis, Mycoplasma |
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episcleritis*
a. presumed etiology b. 2 types c. tx |
a. idiopathic, presumed immune mediated inflammation of sclera
b. simple, diffuse episcleritis: hyperemic & engorged episcleral & conjunctival vessels, often perilimbal corneal edema nodular granulomatous episclerokeratitis (NGE): nodule formation on sclera w/ fleshy red apperance c. topical steroids |
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episcleral melanocytoma (limbal melanoma)*
a. species affected b. biologic behavior |
a. common in dog & cat
b. benign, generally slow growing can invade cornea, iridocorneal angle late in course |
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prolapse of nictitans gland (cherry eye)*
a. cause b. tx |
a. congenital laxity in CT anchoring gland to cartilage at base of nictitans
b. surgical replacement (removal predisposes to dry eye) |
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What is the common result of lesions of the lacrimal system?*
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obstruction to normal tear drainage & epiphora (excessive tearing)
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imperforate lower puncta
a. species affected b. cause |
a. congenital in dogs
b. born w/o opening to lower puncta b/c it’s covered w/ sheet of tissue that normally atrophies --> epiphora |
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dacryoadenitis*
a. definition b. results if chronic c. etiology in dogs d. etiology in cats e. etiology in rats |
a. inflammation of lacrimal gland
b. atrophy, fibrosis, & squamous metaplasia of affected glands w/ resultant loss of secretory function c. presumed immune mediated d. FHV-1 e. coronavirus |
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keratoconjunctivitis sicca (KCS)
a. species affected b. causes c. effects d. tx |
a. common in certain dog breeds
b. presumed immune mediated destruction of lacrimal tissue c. fibrosis of lacrimal glands from dacryoadenitis loss of aqueous portion of protective tear film --> 2º effects on cornea & conjunctiva painful, can lead to blindness if chronic & severe c. cyclosporine |
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What is the major indicator of corneal dz?
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loss of transparency
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What is the response of the cornea to chronic injury?
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undergoes metaplasia to become scleral-like tissue & can respond w/ a full range of inflammatory responses
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What are some responses to corneal injury?
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ulceration
edema vascularization inflammatory cell infiltrate pigmentation fibrosis (scarring) metabolic infiltrate |
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What is corneal ulceration?
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loss of corneal epithelium w/ or w/o stromal loss
initiated by trauma or irritation complicated by bacterial or fungal infection |
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What causes corneal edema?
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implies either epithelial or endothelial damage or loss
whitish to light blue speckled appearance |
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corneal vascularization
a. superficial insult b. deep insult |
will vascularize at depth of lesion (helps localize dz process)
a. superficial corneal vessels that originate from conjunctival vessels (branching, cross limbus) b. deep corneal vessels that originate from episcleral vessels (straight, “brush border”, cannot be seen crossing limbus) |
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What is the oculopupillary reflex?
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CN V --> brain stem --> CN III --> ciliary body & iris sphincter m.
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What is the axonal reflex?
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involves prodromic & antidromic axoplasmic flow along CN V from cornea to iris & ciliary body
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What are the responses of adjacent tissues to corneal injury?
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conjunctival vascular injection & congestion
miosis & ciliary body spasm: oculopupillary & axonal reflexes |
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What are the characteristics of corneal wound healing?*
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epithelial: sliding of cells to cover ulcer, followed by mitosis (rapid rate: 1 mm/day)
stromal: slow & incomplete, new collagen produced generally NOT transparent |
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chronic superficial keratitis
a. other name b. cause c. aggravated by... d. tx |
a. German Shepherd pannus
b. presumed immune mediated rxn to altered corneal antigen c. UV light d. topical steroids |
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What is corneal stromal dystrophy?
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hereditary stromal lipid deposits (occurs in many dog breeds)
occurs as result of a focal alteration in corneal lipid metabolism usually just a cosmetic issue |
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corneal endothelial degeneration
a. cause b. signalment c. effects |
a. age related ↓ in endothelial cell density 2º to endothelial cell necrosis
b. common in older dogs or middle aged Boston terrier, Chihuahua, Dachshund c. progressive corneal edema results: endothelial cells pump water from cornea into anterior chamber & keep cornea “dehydrated” & transparent |
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What is pannus?
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corneal scarring
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corneal sequestrum
a. other names b. signalment c. may be sequelae to.. d. gross lesion |
a. corneal nigrum, necrotizing keratitis
b. only affects cats (predilection for Persian, Siamese, Himalayan) c. FHV-1 keratitis d. central dark pigmented lesion: almost pathognomonic |
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What is the sequence of events in ulcerative keratitis?
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epithelial loss
stromal loss: considered to indicate microbial infection descemetocele: corneal ulcer that has extended to depth of Descemet’s membrane corneal perforation: usually evident by iris tissue & fibrin w/in corneal wound (anterior synechia) |
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What are the most common etiologies of ulcerative keratitis in:
a. dog b. cat c. horse d. cow e. sheep f. goat |
a. endogenous trauma (ex. eyelash disorders, lagophthalmos, KCS, etc.), can initiate 2º microbial infection
b. FHV-1 c. exogenous trauma w/ 2º bacterial or fungal infection d. Moraxella bovis e. Chlamydia f. Mycoplasma |
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refractory superficial corneal ulcers
a. other names b. signalment c. cause |
a. Boxer ulcers, indolent ulcers
b. older dogs (Boxers), horses c. failure of normal wound healing d/t epithelial cell non-adherence generally an epithelial ulcer w/ loose rim of non-adherent epithelium |
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cataract
a. definition b. species affected c. pathogenesis |
a. any opacity in lens
b. most common in dogs, less common in horses, rare in cats c. exposure to wide variety of physical or chemical insults, derangement in lens metabolism |
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stages of cataract development
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incipient: early cataract
-detect using retroillumination: foci of tapetal reflection blocked out immature mature: entire lens opaque (no tapetal reflection) hypermature: lens fibers liquefy, can leak out basement mem (lens capsule) into anterior chamber --> inflammation (lens induced uveitis) |
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What are some etiologies of cataract formation?
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-genetic** (hereditary, familial): most common etiology of cataracts in dogs (~80%); usually adult onset: b’twn 2-6 years old
-postinflammatory: 2º to byproducts of uveal inflammation or trauma to lens capsule, w/ derangement of lens fibers (most common cause in cats & horses) -diabetes mellitus (esp. dogs) -nutritional in puppies, kittens - secondary to retinal degeneration: by products of retinal degeneration (dialdehydes) diffuse thru vitreous to perturb lens metabolism |
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What is the pathogenesis of cataracts associated w/ diabetes mellitus?
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glucose levels in eye ↑ d/t DM --> hexokinase (regulatory enzyme) becomes saturated --> glucose accumulates in lens & begins to be metabolized thru sorbitol pathway via aldose reductase --> sorbitol & fructose accumulate w/in cells of lens since they penetrate cell mems poorly --> intracellular accumulation of solutes & hypertonicity --> accumulation of water w/in lens fibers --> swelling & rupture of lens fibers --> formation of vacuoles in lens cortices --> this continues until entire lens becomes cataractous
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lenticular (nuclear) sclerosis
a. definition b. signalment c. distinguishing from catarct d. distinguishing from corneal edema |
a. progressive lens fiber formation & internal compression of older lens fibers
b. common in old dogs: gray/smoky, translucent lens c. doesn't interfere w/ tapetal reflection like a cataract does d. can see iris w/ nuclear sclerosis, can’t w/ corneal edema in general, doesn't interfere w/ vision |
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lens luxation & subluxation
a. pathogenesis b. normal direction of displacement c. normal sequelae d. etiologies e. clinical sign f. tx |
a. involves damage to lens zonules
b. ventral c. secondary glaucoma d. primary*: familial tendency in terrier breeds 2º to chronic uveitis: cats, horses idiopathic: age-related degeneration of zonules trauma: uncommon e. aphakic crescent: portion of pupil NOT covered by lens (diagnostic for lens displacement) f. remove lens |
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glaucoma
a. definiton b. species affected c. 1st tissues to be damaged by increased IOP d. pathogenesis |
a. pathophysiologic state caused by a sustained ↑ in IOP beyond that compatible w/ normal ocular function
b. one of most common causes of blindness in dogs, less common in cats & horses c. neural retina, optic nerve d. obstruction to flow of aqueous humor anywhere along pathway |
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primary glaucoma
a. cause b. types c. px |
a. abnormality of iridocorneal angle --> ↓ outflow
b. narrow or closed angle: most common type of 1º glaucoma in dog; genetically determined, age related narrowing of iridocorneal angle goniodysgenesis: glaucoma that occurs 2º to abnormal development of iridocorneal angle; instead of pectinate fibers, angle covered w/ broad band of tissue w/ few to no flow holes open angle (rare): obstruction to outflow occurs deep to actual iridocorneal angle c. bilateral, progressive dz w/ guarded long term px for vision |
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causes of secondary glaucoma
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occurs secondary to some other abnormality
- anterior uveitis: #1 cause in cats, horses; swelling of uveal tissues in angle; extensive posterior synechia -lens luxation: pupillary block; vitreous in angle -other: intumescent cataract, introcular neoplasia, hyphema |
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lesions associated with glaucoma
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corneal edema
conjunctival & scleral vascular stasis (hyperemia) paralysis of iris musculature: dilated, non-responsive pupil uveal atrophy retinal atrophy: esp. inner retina or ganglion cell layer optic nerve “cupping” or posterior bowing buphthalmia: enlarged globe (hallmark of chronic glaucoma) corneal scarring from inability to blink eyelids (from buphthalmia) |
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What structures make up the
a. anterior uvea? b. posterior uvea? |
a. iris, ciliary body
b. choroid |
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iris atrophy
a. signalment b. dx |
a. idiopathic degeneration of iris seen in old dogs & cats
b. pilocarpine fails to constrict pupil; incomplete pupillary light reflex |
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iris cysts
a. signalment b. cause c. distinguishing from iris melanoma |
a. common in old dogs, esp. Great Danes, Goldens, Boston terriers (usually asymptomatic)
b. multifocal cystic separation of posterior iris epi, or, rarely, ciliary body epi c. cysts are translucent (can see some of tapetal reflection) |
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iris melanosis
a. definition b. signalment c. monitor for? |
a. accumulation of normal melanocytes in iris
b. benign condition in old dogs c. transformation to malignancy |
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What is..
a. endophthalmitis? b. panophthalmitis? |
a. inflammation of uvea, retina, & ocular cavities (all internal eye structures involved)
b. inflammation of all ocular structures |
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What clinical findings are associated w/ anterior uveitis?
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pain
redness swelling of iris loss of function: ocular hypotony (dec. IOP), breakdown of blood-ocular barrier --> progressive exudate accumulation in anterior chamber (aqueous flare, fibrin, keratic precipitates, hypopyon, hyphema), corneal edema, poor response to topical mydriatic agent |
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What are some etiologies of anterior uveitis?
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trauma
introcular sx secondary to corneal or scleral dz systemic microbial infection: histoplasmosis, brucellosis, toxoplasmosis, ehrlichiosis, canine infectious hepatitis, FIP, FelV, etc. immune mediated: lens induced, canine adenovirus, uveodermatologic syndrome, chronic idiopathic neoplasia |
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What are the 2 types of lens induced uveitis?
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phacolytic (phacotoxic) uveitis: mild anterior uveitis resulting from release of lens proteins from an intact lens capsule; common w/ hypermature cataracts in dogs
phacoclastic uveitis: severe anterior uveitis rsulting from disruption of lens capsule --> massive release of lens proteins into ocular tissues (usually d/t penetrating trauma) |
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uveodermatologic syndrome
a. another name b. signalment c. cause d. effects e. tx f. px |
a. VKH-like dz
b. Arctic Circle dog breeds (ex. Akita, Siberian Husky) c. caused by immune mediated destruction of melanocyte containing tissue (ex. eyes, skin) d. severe panuveitis w/ retinal detachment & dermal depigmentation e. systemic immunosuppressive agents & topical anti-inflammatories f. poor for vision |
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chronic idiopathic uveitis
a. cause b. tx |
50% of anterior uveitis in dogs, 70% in cats, 90% in horses (equine recurrent uveitis)
a. initial injury to blood-ocular barrier (from any insult) --> immune mediated factors are thought to contribute to most cases b. anti-inflammatory therapy |
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What is the most common anterior uveal tumor in dogs, cats, & horses?
What is its biologic behavior? |
melanoma
usually benign, slow growing, & rare to metastasize in dogs & cats |
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diffuse iris melanoma
a. species affected b. biologic behavior c. tx |
a. cats
b. late in course, presents as a change in iris color & 2º glaucoma; diffuse infiltration of anterior uveal tract (progresses slowly); high metastatic potential (50-70%) c. enucleation |
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What is the most common secondary tumor of the uvea?
What might it look like grossly? |
LSA
may look grossly like anterior uveitis: always have LSA as a ddx: thickened iris +/- cellular accumulation +/- mass lesion |
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What is the ocular fundus & what are its layers?
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posterior aspect of eye as viewed ophthalmoscopically
sclera choroid: tapetum, pigment retinal pigment epithelium (RPE): non-tapetal fundus, tapetal fundus sensory retina: retinal vasculature |
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What is the area centralis?
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portion of fundus w/ high concentration of photoreceptors (area of most acute vision)
found temporal (lateral) to optic disc: relatively avascular area |
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thinning or absence of retina
a. causes b. effect on tapetal fundus |
a. atrophy, degeneration
b. hyperreflectivity (focal or diffuse); if assoc. w/ central dark area: tapetal necrosis or RPE hyperpigmentation |
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thickening of retina
a. causes b. effect on tapetal fundus |
a. dysplasia, inflammation, edema, neoplasia
b. hyporeflectivity (focal or diffuse) |
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retinal detachment
a. defintion b. mechanisms c. causes d. effects on tapetal fundus |
a. separation b’twn RPE & sensory retina
b. traction from vitreous: bleeding in vitreous (least common) subretinal fluid accumulation: exudates, edema, blood, liquid vitreous (most common); inflammatory cells push retina off attachment rhegmatogenous: tear in retina, vitreous dissects into subretinal space --> lifts sensory retina off attachment c. trauma, neoplasia, inflammation, vascular & hematologic changes, following intraocular sx, degenerative changes in vitreous (age related) d. hyporeflectivity, whitish discoloration in non-tapetal fundus, folding or retina, giant retinal tear |
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retinal vasculature
a. causes of engorgement b. causes of attenuation c. causes of hemorrhage |
a. hypertension, inflammation, hyperviscosity syndromes, polycythemia
b. atrophy of sensory retina, anemia, glaucoma, occlusive vascular dz, hypotension c. trauma, inflammation, neoplasia, bleeding disorders, vascular |
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choroid
a. causes of thinning b. causes of thickening |
a. atrophy, hypoplasia (ex. Collie Eye Anomaly)
b. inflammation, neoplasia |
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What are some causes of a small optic nerve?
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congenital hypoplasia: genetic lesion in dogs
coloboma: notch/pit like lesion in optic n. (lesion of CEA); may cause optic n. to look too big OR too small; same as cupping, but congenital, NOT acquired cupping: acquired change assoc. w/ chronic glaucoma atrophy & loss of myelin: 2° to optic nerve or retinal injury |
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What are some causes of a large optic nerve?
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excessive myelinization: normal; may be seen in sporting breed dogs
optic neuritis (inflammation) papilledema: swelling of optic nerve (rare) neoplasia: rare coloboma |
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Collie Eye Anomaly
a. pathophysiology b. lesions |
a. choroidal & retinal hypoplasia (generally focal); inherited in collies
b. (bilateral): choroidal hypoplasia, tortuosity of retinal vasculature, optic disc colobomas, retinal detachment (in severe cases) |
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spontaneous retinal dysplasia
a. pathophysiology b. etiologies c. lesions |
a. abnormal differentiation of retina
b. familial in certain dog breeds (Lab, Cocker), Hereford cattle -2° to retinal necrosis, generally from retinal inflammation in utero (feline panleuk, BVD, bluetongue virus) c. linear or punctuate retinal folds – hyporeflective areas of tapetal fundus, Y shaped folds, retinal detachment (if severe) |
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progressive retinal atrophy
a. pathophysiology b. signalment |
a. biochemical defect in retinal metabolism, affecting rod &/or cone photoreceptors
b. dogs b'twn 2-8 yo |
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hypertensive chorioretinopathy
a. pathogenesis b. signalment c. lesions |
a. sustained ↑ in systolic BP --> necrosis of vascular endothelium of retina & choroid
b. acute vision loss & dilated pupils in cats > 10 yo; occurs 2° to renal dz or may be primary; some cats also have HCM c. retinal hemorrhage & detachment, tortuous retinal vessels, retinal degeneration |
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Inflammation or neoplasia of orbit results in..?
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exophthalmos (protrusion of globe)
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What are some causes of inflammation of the orbit?
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-bacteremia
-penetrating wound -extension from adjacent tissues: most common cause; from oral cavity (tooth root abscess), nasal cavity, sinuses |
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What tumors affect the orbit in
a. dogs b. cats c. horses d. cattle |
a. usually malignant, locally invasive, & 1° to orbit or periorbital tissues (OSA, MCT, adenocarcinoma, fibrosarcoma, malignant melanoma, lacrimal gland tumor, optic n. tumors, metastatic)
b. usually malignant, locally invasive, & 1° to orbit or periorbital tissues (LSA, SCC) c. SCC d. LSA (orbit is 1 site of predilection) |
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What is enophthalmos?
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sunken globe caused by any painful stimulus
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What are some common ocular sites for SCC in horse, cow, and cat?
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horse: orbit, eyelid, conjunctiva, 3rd eyelid
cow: eyelid, conjunctiva, 3rd eyelid cat: orbit, eyelid, 3rd eyelid (rare) |
