Ocular Emergencies

Question 1

What nerves control movement of the globe?

Answer 1

• CN III, IV VI, and extraocular muscles, allowing 240 degree vision

Question 2

MAP directly affects which part of the eye?

Answer 2

Aqueous humor

Question 3

Pupil constriction is controlled by____

Answer 3

The PNS

Question 4

Pupil dilation is controlled by ____

Answer 4

The SNS

Question 5

In what order should routine ocular testing be performed?

Answer 5

STT –> Fluoroscein stain –> Tonometry

Question 6

Why is triple antibiotic ointment (neo/poly/bac) not recommended in cats?

Answer 6

Due to reports of anaphylaxis

Question 7

What is glaucoma?

Answer 7

A congenital disease in which there is a decrease in aqueous outflow, leading to an IOP >25mmHg. Increased pressures reduce blood supply to the retina and optic nerve, necessitating prompt tx to preserve vision

Question 8

What breeds are predisposed to glaucoma?

Answer 8

• English/American cockers
• Siberians
• Toy poodles
• Bassets

Question 9

Is glaucoma more common in dogs or cats?

Answer 9

Dogs; rarely cats

Question 10

Are one or both eyes affected in glaucoma?

Answer 10

Bilateral disease, but often one eye is affected first

Question 11

What is the most common cause of secondary glaucoma in dogs?

Answer 11

Lens induced uveitis secondary to cataract formation

Question 12

What is the usual age of onset for glaucoma?

Answer 12

Dogs 4-10 years

Question 13

At what IOP is mannitol indicated to shrink the vitreous humor?

Answer 13

40-60

Question 14

What medications can be used for glaucoma?

Answer 14

• Carbonic anhydrase inhibitors (Drozolomide, Brinzolamide)
• Beta adrenergic antagonists (Timolol)
• Prostaglandin analogues (Lantanoprost; not effective in cat, contraindicated in lens luxation)

Question 15

What tell tale sign is seen in uveitis?

Answer 15

Aqueous flare

Question 16

Why does uveitis have low IOP?

Answer 16

Decreased IOP results from decreased aqueous production

Question 17

Etiology of uvieitis

Answer 17

• Intraocular inflammation is initiated by local tissue injury
• Damaged tissue and microorganisms release tissue factors and inflammatory mediators that cause vasodilation and increased vascular permeability

Question 18

What is iris bombe?

Answer 18

An accumulation of aqueous humor behind the iris causing it to billow forward

Question 19

How is uveitis treated?

Answer 19

• Treat underlying cause
• Mydriatics to dilate pupil and relieve muscle spasms of iris and ciliary body

Question 20

True or false: Anterior lens luxation is an emergency

Answer 20

True

Question 21

True or false: Posterior lens luxation is an emergency

Answer 21

False

Question 22

What breeds are predisposed to primary lens luxation?

Answer 22

• Terriers
• Border Collies
• Brittany Spaniels
• Aus cattle dogs
• Shar peis

Question 23

Lantanoprost is contraindicated in _____?

Answer 23

Anterior lens luxation

Question 24

Lens luxation can lead to what other problems?

Answer 24

Glaucoma due to obstruction of fluid outflow, and uveitis

Question 25

The use of corticosteroids is contraindicated in ___?

Answer 25

Any case where the cornea is injured

Question 26

What two signs are a favorable indication of function in proptosis?

Answer 26

- A consensual reflex in the unaffected eye - A miotic pupil in the affected eye

Question 27

What is hyphema?

Answer 27

- Blood collection in the anterior chamber of the globe - Can lead to glaucoma due to fibrin collection not allowing drainage of aqeuous humor

Question 28

What is one of the leading causes of incurable canine vision loss?

Answer 28

SARDS

Question 29

What is SARDS?

Answer 29

- Characterized by acute onset of blindness due to loss of photoreceptor function - Majority of dogs also show systemic abnormalities suggestive of hyperadrenocorticism

Question 30

What breeds are predisposed to SARDS?

Answer 30

- Daschunds - Chinese pug - Min schnauzer - Bichon - Beagle - Brittany - Pom

Question 31

What is progressive retinal atrophy?

Answer 31

- A congenital inherited photoreceptor dysplasia seen in many dogs - Progresses slowly over years - No effective treatment

Question 32

What is retinal detachment?

Answer 32

- Separation of the retina from underlying choroid - Anatomically, separation of the photoreceptor layer from the retinal pigment epithelial layer of retina

Question 33

What are the 5 main types of retinal detachment?

Answer 33

- Serous detachment (accumulation of exudates or blood under retina) - Traction band detachments (fibrous bands contract and pull retina off) - Vitreous degeneration (liqueification of vitreous allows it to seep under retina) - Congenital (not a true detachment - failure of embryonic layers to unite - seen in collie eye anomaly) - Iatrogenic (after cataract surgery)

Question 34

What does the presence of blood vessels in the cornea always indicate?

Answer 34

Ongoing corneal pathology

Question 35

What is the leading cause of complicated corneal ulcers?

Answer 35

The use of topical steroid in a patient with a corneal defect

Question 36

What demographic is prone to melting ulcers?

Answer 36

Brachycephalics

Question 37

What is a melting ulcer?

Answer 37

The cornea is made of collagen and the ulcer produces a collagenase that eats through the cornea

Question 38

How can melting ulcers be treated?

Answer 38

- Serum eye drops can stop collagenic activity - NAC

Question 39

What breed is more susceptible to KCS?

Answer 39

Burmese

Question 40

What is pannus?

Answer 40

- The superficial vascularization of the cornea with infiltration of granulation tissue - Immune mediated disease

Question 41

What is corneal sequestrum?

Answer 41

- Occurs when an area of the cornea has become sequestered and dies - Patient usually has a history of corneal injury

Question 42

Surgical treatment of an ulcer is recommended when the depth of the ulcer is ____?

Answer 42

>2/3 normal thickness

Question 43

What is Horner's?

Answer 43

- Oculosypathetic paresis - Secondary to loss of sympathetic innervation to the eye

Question 44

What signs are seen in Horner's?

Answer 44

- Ptosis - Miosis - 3rd eyelid protrusion - Enophthalmos

Question 45

What are the two classifications of Horner's?

Answer 45

- Preganglionic: interruption of the nerve between spinal cord and synapse in ganglion - Trauma, head/neck surgery, brachial plexus injury, intracranial or thoracic neoplasia - Postganglionic; nerve has been interrupted between synapse and eye itself - Otitis media/interna, idiopathic

Question 46

Approximately what % of Horner's in dogs is idiopathic?

Answer 46

50%

Question 47

What medication can be utilized to localise a causative lesion of Horner's?

Answer 47

- Phenylephrine, an alpha 1 adrenergic agonist - If lesion is postgalionic, ocular signs will resolve within 5 minutes - If lesion is preganglionic, signs will NOT resolve quickly

Question 48

What is buphthalmos?

Answer 48

Enlargement of the globe

Question 49

What is panophthalmitis?

Answer 49

Inflammation of all structures or tissues of the eye

Question 50

What is epiphora?

Answer 50

Watery eyes

Question 51

What is melbomian gland abscess/adenoma (chalazion)?

Answer 51

The chronic or acute swelling of one or more melbomian glands along the upper and lower eyelids

Question 52

What is symblepharon?

Answer 52

The adhesion of the conjunctiva to the lid and eyeball that occurs in utero