Ocular Pharmacology

Question 1

Is pupillary dilation (mydriasis) controlled by parasympathetic or sympathetic pathway?

Answer 1

Sympathetic

Question 2

Is pupillary constriction (miosis) controlled by parasympathetic or sympathetic pathway?

Answer 2

Parasympathetic

Question 3

What are the two things necessary to achieve pharmacologic pupil dilation?

Answer 3

Stimulate dilation of pupil

Prevent constriction of pupil

Question 4

What type of agonist is used to directly stimulate pupil dilation?

Answer 4

Adrenergic agonist

Question 5

Which adrenergic agonist is most commonly used for pupil dilation?

Answer 5

Phenylephrine (alpha-1 agonist)

Question 6

What type of antagonist is used to prevent constriction of the pupil?

Answer 6

Muscarinic antagonist

Question 7

Which muscarinic antagonist is most commonly used to prevent constriction of pupil?

Answer 7

Tropicamide

Question 8

What can be used to reverse pharmacologic mydriasis?

Answer 8

Alpha blocker called Dapiprazole (no longer available in US)

Question 9

What are the 5 agents used for pharmacologic mydriasis and what is their mechanism of action?

Answer 9

Atropine
Cyclopentolate
Homatropine
Scopalomine
Tropicamide

All non-selective muscarinic antagonists (prevent constriction of pupil)

Question 10

Which pharmacologic mydriasis agents are long-acting?

Answer 10

Atropine

Cyclopentolate

Question 11

What are systemic side effects that can occur from use of the muscarinic antagonists (parasympatholytics)?

Answer 11

"Mad as a hatter, dry as a bone"
Blocks DUMBBeLSS, causing:
Reduced GI motility
Urinary retention
Mydriasis
Bronchodilation
Tachycardia
Decreased lacrimation (dry eye)
Decreased sweat (dry skin)
Decreased salivation (dry mouth)

Question 12

What are the two major types of glaucoma?

Answer 12

Open angle glaucoma

Closed angle glaucoma

Question 13

How can you recognize acute angle closure glaucoma?

Answer 13

Red painful eye
Nausea, vomiting
Blurred vision
Fixed mid-dilated pupil (pressure is increased and pupil can't work at higher pressure)
Hazy cornea

Question 14

What is the only treatable risk factor of glaucoma?

Answer 14

Intraocular pressure

Question 15

How is acute angle closure glaucoma treated?

Answer 15

Iridotomy (make a hole in iris)

Question 16

What categories of drugs can be used in treatment of glaucoma (i.e. lower IOP)?

Answer 16

Beta antagonists
Alpha-2 agonists
Muscarinic agonists

Question 17

How do beta antagonists lower IOP?

Answer 17

Decrease production of aqueous humor in ciliary body

Question 18

What are the beta antagonists commonly used to lower IOP?

Answer 18

Timolol

Question 19

How do alpha-2 agonists lower IOP?

Answer 19

Decrease production of aqueous humor in ciliary body

Also increase outflow (by preventing pupil dilation)

Question 20

What are the alpha-2 agonists commonly used to lower IOP?

Answer 20

Brimonidine

Apraclonidine

Question 21

How do muscarinic agonists lower IOP?

Answer 21

Cause miosis, which opens iridocorneal angle to improve drainage of aqueous humor

Question 22

What are the muscarinic agonists commonly used to lower IOP?

Answer 22

Pilocarpine

Carbamycholine

Question 23

What are the 3 major characteristics of Horner syndrome?

Answer 23

Ptosis
Miosis
Anhydrosis

Question 24

What two drugs are necessary to test for Horner’s syndrome?

Answer 24

Cocaine

Amphetamine

Question 25

What is the purpose of cocaine in diagnosis of Horner’s syndrome?

Answer 25

Cocaine blocks reuptake of NE, so should have increased NE and therefore dilation of pupil

No dilation of pupil upon cocaine administration = no NE being released by postganglionic neuron = defect somewhere in oculosympathetic pathway (could be pre or post ganglionic)

Question 26

What is the purpose of amphetamine in diagnosis of Horner’s syndrome?

Answer 26

Amphetamine is an adrenergic agonist and stimulates release of NE, so should cause release of NE from postganglionic neuron and dilation of pupil

No dilation of pupil upon amphetamine administration = defect is at postganglionic neuron

Dilation of pupil with amphetamine but no dilation with cocaine = defect is further up the oculosympathetic pathway

Question 27

What is a possible cause of Horner’s syndrome that can be diagnosed by chest xray?

Answer 27

Pancoast tumor in the apical lung