Ophthalmology

Question 1

What is normal IOP in dogs?

Answer 1

10-20 mmHg

Question 2

List 3 breeds that are predisposed to primary glaucoma

Answer 2

1) Beagles
2) Cocker spaniels
3) Basset hounds
4) Samoyeds

Question 3

What are the three treatments for acute glaucoma? What are the MOA for each treatment?

Answer 3

1) Mannitol IV (1-2 g/kg IV over 30 minutes) - osmotic effect (last for 6 hours) and dehydrate the vitreous
2) Carbonic anhydrase inhibitor (e.g. dorzolamide) - decrease aqueous production
3) Synthetic prostaglandin (e.g. latanoprost) - increase aqueous outflow

Question 4

What are three most common causes of acute blindness in dogs and cats?

Answer 4

1) Sudden acquired retinal degeneration syndrome or SARDS (dogs)
2) Ivermectin toxicity (dogs)
3) Enrofloxacin toxicity (cats)

Question 5

List 5 mechanisms of secondary injury in TBI

Answer 5

1) Intracellular influx of Na and Ca
2) Glutamate accumulation
3) ROS injury
4) Inflammatory response
5) Loss of autoregulation

Question 6

What MGCS number showed 50% survival in 48 hours in dogs with TBI?

Answer 6

8

Question 7

True or False: Prophylactic anti-epileptics is recommended in human with TBI for 7 days post-injury.

Answer 7

True

• Vet med → unknown

Question 8

What is the recommended temperature range in therapeutic hypothermia in human?

Answer 8

33 - 35 C (91.4 - 95 F)

• Avoid shivering! Mechanical ventilation & General anesthesia are required.

Question 9

What brain lesions will lead to mydriasis and what will lead to miosis?

Answer 9

Mydriasis (loss of parasympathetic): CN III, midbrain
Miosis (loss of sympathetic): thalamus, hypothalamus, pons, cerebrum

Question 10

What is the dose of ketamine for dogs with refractory epilepsy?

Answer 10

5 mg/kg IV, followed by 5 mg/kg/hr

Question 11

Which class of antibiotic is known to decrease tear production?

Answer 11

Sulfa-containing drugs

Question 12

Which two CNs are affected in neurogenic KCS?

Answer 12

CN 5, 7 (parasympathetic fibers)

Mainly CN 7

Question 13

What is descemetocele? How do you diagnose it?

Answer 13

The exposure or protrusion of the Descemet membrane on the anterior surface of the cornea
Fluorescein stain → ulcer floor not pick up the stain

Question 14

Name two eye conditions that cause miosis.

Answer 14

Anterior uveitis
Horner’s syndrome
Drug (e.g. pilocarpine and latanoprost)

Question 15

Why is atropine contraindicated in glaucoma?

Answer 15

It can cause closure of iridocorneal angle and block the aqueous humor

Question 16

List 5 differential of mydriasis.

Answer 16

Atropine administration
Glaucoma
Catecholamine release
Optic nerve or end-stage retinal disease
Iris atrophy

Question 17

True or False: Patients with retinal disease will still have PLR and dazzle reflex; but patients with optic nerve disease won’t have both reflexes.

Answer 17

True

Question 18

What is normal intra-ocular pressure (IOP) in dogs and cats?

Answer 18

10-30 mmHg

Question 19

What is normal Schirmer tear test (STT) in dogs and cats?

Answer 19

Dogs: 12 mm/min
Cats: 5-20 mm/min

Question 20

What is the rationale of using atropine in anterior chamber uveitis?

Answer 20

To control pain, photophobia
To prevent the formation of posterior synechiae

Question 21

Why shouldn’t you use prostaglandin analogue (e.g. latanaprost) in patient with glaucoma and concurrent anterior lens luxation or uveitis?

Answer 21

Prostaglandin analogue can cause miosis → trap the lens & cause posterior synechiae in uveitis

Question 22

What is the rationale of using 𝜷-blocker (e.g. Timolol) in patients with glaucoma?

Answer 22

Block SNS ending in the ciliary epithelium → decreased aqueous humour production