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Flashcards in Opthalmology Deck (33)
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1
Q

Strabismus

A

Abnormal ocular globe position
– Bilateral hereditary condition – Secondary
• Orbital neoplasia, CN dysfunction from listeriosis or polioencephalomalacia

2
Q

Types of strabismus

A

– Divergent (exotropia) - a form of strabismus where the eyes are deviated outward.
– Convergent (esotropia) -a form of strabismus where the eyes are deviated inward.

3
Q

exophthalmos

A

abnormal protrusion of the eyeball or eyeballs.

4
Q

Nystagmus

A

Horizontal movement of the ocular globe

5
Q

Nystagmus - congenital & aquired signalment

A

– Hereditary congenital:
• Ayshires, Guernseys and Holsteins
– Acquired:
• Calves that develop dysfunction of their peripheral
vestibular system or cerebellum
• Following an ear infection or systemic disease

6
Q

Microphthalmia - what is it? causes? sequelae?

A
Congenitallysmalleyes
– Inherited or acquired 
     • BVD
– Unilateral or bilateral – Small ocular globe
     • Protrusion of third eyelid
– Ocular anomalies
     • Cataracts, retinal dysplasia
7
Q

Entropion

A
The inversion of eyelids – Neonatal cattle
– Secondary
• Systemic diseases
• Corneal ulcers – Lacrimation
– Bilateral:
• Result in visual deficits
• Impact on growth / weight gain
8
Q

Entropion - Treatment

A

– Temporary correction with placing vertical mattress sutures
– Permanent correction with the removal of a skin crescent with
wound closure
– Topical antibiotics + atropine if corneal ulcers present

9
Q

Dermoid

A

Ectopic skin cells
– Third eyelid, conjunctiva, cornea – Herefords:
• Genetically predisposed – Hair follicles, skin glands
– Epiphora
– Treatment:
• Surgical excision

10
Q

Infectious Bovine Keratoconjunctivitis (IBK) - pathogens that cause this:

A

– Moraxella bovis:
• Gram-negative bacillus
– Secondary pathogens:
• Mycoplasma and IBR

11
Q

Infectious Bovine Keratoconjunctivitis (IBK) - trasmission, signalment

A

– Transmission: flies
– Summer outbreaks
– Herefords, Hereford crosses, Murray Grays
• Highest susceptibility

12
Q

Infectious Bovine Keratoconjunctivitis (IBK) - clinical signs, progression

A

• Clinicalsigns: – Initial stages:
• Hyperemic conjunctiva • Blephrospasms
• Serous discharge
– Progression:
• Mucopurulent discharge
• Corneal edema, ulceration, neovascularization • Corneal perforation
– Secondary uveitis is also commonly seen

13
Q

Infectious Bovine Keratoconjunctivitis (IBK) - treatment

A
– Controlling the fly population
– Isolating affected cattle
– IM long-lasting tetracycline repeated
in 72 hours
   • Topical tetracycline (TID)
   • Topical atropine (BID)
– Corneal rupture:
   • Conjunctival flaps or enucleation
– Vaccination: controversial
14
Q

IBR

A

– Ocular and respiratory disease
– Mimics IBK clinical signs – Diagnosis:
• Viral cultures or paired serum samples for titers
– Treatment:
• Controlling secondary bacterial infections with topical antibiotic ointment
– Prevention:
• Vaccinations

15
Q

Uveitis

A

Septicemia, endotoxemia, navel ill (calves)
• Listeriamonocytogenesinfection
– Secondary to feeding of big-bale silage
• Haemophilussomnus(infectiousthromboembolic meningoencephalitis)
– Conjunctival and episcleral hyperemia, miosis, aqueous flare, hypopyon, vitritis, retinal hemorrhages
– Anti-inflammatory drugs (topical and systemic)
– Topical atropine
– Systemic antibiotics

16
Q

Hyphema: causes

A

Uveitis or trauma

17
Q

Malignant Catarrhal Fever: signalment, clinical signs, diagnosis

A
Cattle,llamas,deer,bison 
– Herpes virus
– Clinical signs:
     • Lacrimation, serous to mucopurulent ocular discharge, episcleral and conjunctival hyperemia, severe corneal edema, miosis, hypopyon and iritis
– Diagnosis:
     • Histopathology
– Treatment:
     • High mortality rate
– Related to progression of uveitis
18
Q

Cataracts: Types, signalment, treatment

A

Congenital, genetic or acquired – Genetic:
• Herefords, Holsteins and Jerseys – Acquired:
• BVD can be transmitted from the mother in the early to mid stages of the pregnancy
• Anterior uveitis
– Treatment:
– Monitor
– Cataract surgery

19
Q

Blindness: Causes, types, diagnosis, treatment

A

• Vitamin A deficiency – Night blindness
• Followed by day blindness
– Bone growth at the optic foramen
• Results in a constriction of optic nerve – Diagnosis:
• Serum levels <25mg/dl – Treatment:
• Vitamin A supplementation
KN Gelatt. Color Atlas of Veterinary Ophthalmology

20
Q

Retinal degeneration

A

• Ingestionof: – Cattle:
• Male fern (Dryopteris felix mas) – Sheep/goats:
• Blind grass (Stypandra glauca) – Blindness
• Optic nerve atrophy
• Neuropathy – No antidote
KN Gelatt. Color Atlas of Veterinary Ophthalmology

21
Q

Squamous Cell Carcinoma *** Exam

A

• Mostcommonoculartumour
• Hereford:predilection
– Ultraviolet light and absence of periocular pigment are
predisposing factors to developing tumors
• Lesions have the potential to regress or to develop into a malignant tumor

22
Q

Squamous Cell Carcinoma *** Originates

A

• Eyelid margin, palpebral conjunctiva, third eyelid, limbus or cornea
• Lesions are usually broad based and vascular with an irregular cobbled-stone appearance.
– Rapidly growing lesions may also ulcerate and have necrotic tissue.

23
Q

Squamous Cell Carcinoma *** Treatment

A

– Surgical excision with large margins
• Exenteration of the orbital contents – Adjunctive therapy:
• Cryotherapy – Metastasis
• Regional lymph nodes

24
Q

Papillomas: what is it? treatment?

A
– Pedunculated with a cauliflower
appearance
– Margin of the third eyelid – Similar appearance to SCC 
– Treatment
• Surgical excision 
• Tend not to recur
25
Q

Lymphoma: what is it? lined to?

A

• Retrobulbarmass
– Exophthalmia +/- strabismus
– Unilaterally or bilaterally
– Exposure keratitis
– Severe cases: visual impairment and blindness
• Linked:bovineleukemiavirus (BLV)
– Approximately 5% of BLV positive cows develop lymphosarcoma

26
Q

Lymphoma: diagnosis, treatment, prevention

A
• Diagnosis
 – Cytology or histopathology
• Treatment:
– Palliative third eyelid flap
• Prevention: – BLV testing
– Prompt isolation
– Control of blood sucking insects
27
Q

Camelid Ocular Diseases: Congenital nasolacrimal duct disorders - name 3 types, treatment?

A

– Atresia of duct or puncta
– Epiphora
– Dacryocystogram
– Create opening with incision through imperforated mucosa; Leave tubing in for 6 weeks

28
Q

Camelid ocular diseases

A

Conjunctivitis
– Usually secondary to corneal ulcer, uveitis, environment
– Primary infection: chlamydiae, thelazia
– Dilation of conjunctival blood vessels
– Treat underlying cause

29
Q

Camelid ocular diseases - corneal ulceration

A
– Similar to other species: simple, indolent, complex – Topical antibiotics in all cases
– Topical atropine if miosis
– Grid keratotomy if indolent
– Serum if melting

30
Q

Camelid ocular diseases: Corneal abscess

A
– Similar to horses
• Intact epithelium • Bacterial or fungal
– Topical bactericidal antibiotics
– Topical anti-fungal
• If no response
• If seen deep within corneal stroma
31
Q

Camelid ocular diseases: Cataracts: what are they? how can it be caused? treatment?

A

– Opacity of the lens
– Visual impairement?
– Lens induced uveitis – Monitor or surgery

32
Q

Camelid ocular diseases: Uveitis: types, work-up, treatment

A
– Primary
• Infectious
– Septicemia
– EHV, Toxo, Aspergillosis • Trauma
– Secondary
• Corneal ulcer, cataract
– Work-up
• PE, blood tests
– Anti-inflammatory therapy
33
Q

Camelid ocular diseases: Intraocular neoplasia, name 3 types

A

– Medulloepithelioma
– Retinoblastoma
– melanoma