Pharmacology

Question 1

What is the sandwich that topical drugs have to penetrate to get into the cornea?

Answer 1

lipi:water:lipid

Question 2

Is the epithelium lipophilic/phobic?

Answer 2

philic

Question 3

Is the stroma lipophilic/phobic?

Answer 3

lipophobic

Question 4

How far through the cornea do lipi soluble drugs penetrate?

Answer 4

epithelium

Question 5

What do water soluble drugs penetrate in the cornea?

Answer 5

stroma

Question 6

What is an example of a drug that has both liophilic and hydrophilic proerties and so can penetrate the cornea easily?

Answer 6

chloramphenicol

Question 7

How does ocular surface inflammation affect the nature of the cornea epithelium?

Answer 7

reduces the hydrophobic nature

Question 8

What can be added to a topical steroid to make it more hydrophobic?

Answer 8

alcohol or acetate

Question 9

What can be added to a topical steroid to make it more hydrophilic?

Answer 9

phosphate

Question 10

What is prednisolone phosphate used?

Answer 10

for cornea disease or when want low dose steroids (as hydrophilic)

Question 11

What is benzalkonium?

Answer 11

a preservative

Question 12

In addition to its preservative action, what else does benzalkonium do?

Answer 12

disrupts the lipi layer of the tear film, aiding penetration of hydrophilic drugs

Question 13

How can the systemic absorption of topical drugs be prevented?

Answer 13

punctal occlusion

Question 14

Where are intravitreal injections done?

Answer 14

after corneal limbus there is 3/4mm before the retina begins if hit retina can cause retinal detachment

Question 15

What are the anti-inflammatory agents used in the eye?

Answer 15

steroids; topical NSAIDs; anti-histamines; mast cell stabilisers

Question 16

When are topical steroids used?

Answer 16

post op cataracts; uveitis; to prevent corneal graft rejection

Question 17

What are the local effects of steroids?

Answer 17

cataracts; glaucoma; exacerbation of viral infection

Question 18

What is the only modifiable risk factor in glaucoma?

Answer 18

raised intra-ocular pressure

Question 19

How do patients usually present with glaucoma?

Answer 19

usually asymptomatic- is screened for by optometrists- visual loss

Question 20

What is LA used for?

Answer 20

FB removal; tonomtery(IOP); corneal scraping; comfort

Question 21

How do LA wokr?

Answer 21

block sodium channels, impeding nerve conduction

Question 22

What is the most commonly used diagnostic dye?

Answer 22

fluorescein

Question 23

What are the uses of fluorescein?

Answer 23

shows corneal abrasions; tonometry; diagnosing nasolacrimal obstruction; angiography

Question 24

How do mydriatics work?

Answer 24

pupil dilation by blocking parasympathetic supply to iris

Question 25

What are the side effects of mydriatics?

Answer 25

blurring; AACG (acute glaucoma)

Question 26

How do sympathomimetics work?

Answer 26

act of sympathetic system causing pupils to dilate

Question 27

What can ethambutol cause?

Answer 27

optic neuropathy

Question 28

How do drugs for glaucoma work?

Answer 28

by decreasing IOP by opening up drain or decreasing humour production