Pharmacology

Question 1

where does occular obsorption come from

Answer 1

the cornea

Question 2

where does systemic absorption of drugs by the eye come from

Answer 2

conjunctiva and mucous of the nasopharynx

Question 3

what are the routes of topical eye administration

Answer 3

drops (more frequently)

ointment (sooth eye but blur vision)

Question 4

what is the stroma

Answer 4

a mesenchymal tissue, the thickest layer of the cornea, and is ‘sandwiched’ between the epithelium and the inner endothelium
made of collagen

Question 5

what makes up the tear film

Answer 5

lipid, water, lipid barrier

Question 6

is epithelium lipophilic/phobic and

hydrophilic/phobic

Answer 6

epithelium is hyrophobic and lipophillic

Question 7

is stroma lipophilic/phobic and

hydrophilic/phobic

Answer 7

stroma is lipophobic and hydrophillic

Question 8

what types of drugs penetrate the epithelium of the eye

Answer 8

lipid soluble

Question 9

what types of drugs penetrate the stroma

Answer 9

water soluble drugs

Question 10

what drugs are good at crossing the cornea

Answer 10

drugs with a LMW

Question 11

what type of drugs get through the eye furthest

Answer 11

lipid soluble

or drugs that are both lipo and hydro philic (chloramphenicol)

Question 12

what drugs will not get through the surface of the eye

Answer 12

lipophobic (water soluble)

Question 13

what can increase penetration of a drug into the eye

Answer 13

ocular surface inflammation (reduces the hydrophobic nature of the endothelium- innermost layer of the cornea)

Question 14

what in tear film might impede drug penetration

Answer 14

lipid layer

Question 15

what limits hydrophilic drugs in the eye

Answer 15

epithelium

Question 16

what limits hydrophobic drugs in the epithelium

Answer 16

stroma (better penetration in these drugs)

Question 17

what properties do topical steroids for the eye need

Answer 17

hydrophobic and hydrophilic capability

alcohol/ acetate makes steroids more hydrophobic

phosphate makes it more hydrophilic

Question 18

when is prednisolone acetate used

Answer 18

post op, intraocular inflammation cataracts

hydrophic, good penetration in uninflamed cornea

Question 19

what is prednisolone phosphate used

Answer 19

cornea disease/ when you want low dose steroids

hydrophilic, poor penetration in uninflamed cornea

Question 20

what pathogen is the most common to cause infection in contact lenses

Answer 20

pseudomonas

Question 21

what is the role of benzalkonium

Answer 21

disrupts lipid layer of tear film, aids penetration of some drugs

used to lower IOP in glaucoma

Question 22

what a side effect of benzalkonium

Answer 22

makes eyes red and black

Question 23

what can limit systemic absorption of a drug at the nasopharynx

Answer 23

punctal occulsion

Question 24

what are the routes of administration of drugs into the eye

Answer 24

topical 
sub conjunctival 
subtenons (fibrous layer that starts at the limbus- this route will go back into the orbit)
intra vitreal 
intracameral 
oral 
intra venous

Question 25

what anti inflammatory agents are used in the eye

Answer 25

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

Question 26

what drugs for allergic reactions (hayfever/ allergic conjunctivitis)

Answer 26

anti-histamines, mast cell stabilisers

Question 27

what are the actions of steroids in the eye

Answer 27

suppress inflammation, allergy and immune responses

Question 28

when are steroids used topically in the eye

Answer 28

post op cataracts uveitis prevent corneal graft rejection

Question 29

what is uveitis

Answer 29

inflammation of the uvea (iris, ciliary body and choroid)

Question 30

what route of steroids for inflammation at the back of the eye

Answer 30

systemic steroids

Question 31

what are the features of temporal arteritis

Answer 31

sudden onset temporal pain, jaw claudication multinucleated giant cells can have vague visual symptoms/ complete visual loss is a blinding condition

Question 32

how is temporal arteritis treated

Answer 32

systemic steroids 40 if no visual disturbance, 60 if affected

Question 33

what does the optic disc look like in anterior ischaemic neuropathy

Answer 33

swollen due to infarction of the optic nerve

Question 34

what are the local effects of steroids

Answer 34

cataract, glaucoma, exacerbation of viral infection

Question 35

what are the systemic effects of steroids

Answer 35

gastric ulceration, immunosuppression, osteoporosis, weight gain, diabetes, neuropsychiatric effects

Question 36

what can you give to reduce gastric ulceration in steroids

Answer 36

PPI

Question 37

list the topical eye steroids from most to least potent

Answer 37

FML Predsol (prednisolone phosphate) Betamathasone Dexamethasone/ prednisolone acetate

Question 38

when are NSAIDs used in the eye

Answer 38

for pain relief/ anti inflammatory

Question 39

what can you give for corneal abrasion

Answer 39

NSAIDs | local anaesthetic will stop it healing

Question 40

what is glaucoma

Answer 40

group of disorders characterised by a progressive neuropathy (damage to the optic nerve) resulting in characteristic field defects

Question 41

what is the only modifiable risk factor for glaucoma

Answer 41

raised IOP

Question 42

what happens to the cup in glaucoma

Answer 42

gets bigger

Question 43

how do you functionally test for glaucoma

Answer 43

field test

Question 44

what can slow the progression of glaucoma

Answer 44

lowering IOP - either by reducing the production of aqueous or unblock the drain

Question 45

what visual defects in glaucoma

Answer 45

not tunnel vision - brain fills in the gap

Question 46

what glaucoma medications open the drain

Answer 46

prostanoids (lanaoprost) | parasympathomimetic (pilocarpine)

Question 47

what glaucoma medication prevents the absorption of aqueous

Answer 47

beta blockers

Question 48

what glaucoma medications stop production of aqueous and open the drain

Answer 48

carbonic anhydrase inhibitors (topical- dorzolamide, systemic- acetazolamide) (opens drain and reduces production of aqueous) alpha adrenergic agonist (brimonidine) ( turns of production and opens drain via vasodilation)

Question 49

why do people with glaucoma wear tinted glasses

Answer 49

to reduce glare

Question 50

what is the main route of antibiotic administration in endophthalmitis

Answer 50

intravitreal

Question 51

what drugs are delivered intra vitreal

Answer 51

``` antibiotics intra ocular steroids anti VEGF (reduce oedema) ```

Question 52

what is a hypopyon

Answer 52

inflammatory cells in the anterior chamber of the eye

Question 53

how do local anaesthetics work within the eye

Answer 53

blocks sodium channels and impedes nerve conduction

Question 54

what does diagnostic dye fluorescein show

Answer 54

``` shows corneal abrasion dendritic ulcer leaks (seidel test) tonometry nasolacrimal duct obstruction angiography ```

Question 55

what do mydriatics do (tropicamide, cyclopentolate)

Answer 55

``` dilate pupils, block parasympathetic supply to the iris cause cyclopegia (stop lens from focusing) ```

Question 56

what are the side effects of mydriatics

Answer 56

AACG, blurring

Question 57

why do you dilate the pupil

Answer 57

to see the back of the eye

Question 58

what is the presentation of acute angle closure glaucoma

Answer 58

very painful, throwing up, sudden onset headache, pupil mid dilated not reacting

Question 59

what do sympathomimetics do

Answer 59

act on sympathetic system causing the pupil to dilate | e.g. tropicamide, atropine- can cause cyclopegia

Question 60

what is the long term use of atropine

Answer 60

given to child with a squint as takes 7-9 days to wear off- will help strengthen other eye

Question 61

why dont systemic drugs reach the eye

Answer 61

inner and outer retinal blood brain barrier

Question 62

what do miotics do

Answer 62

constrict the pupil (pilocarpine)

Question 63

what can alcohol and ethambutol (TB) cause

Answer 63

optic atrophy

Question 64

what can rifampicin cause

Answer 64

red tears, stain contact lenses

Question 65

what can digoxin cause

Answer 65

changes in colour appreciation

Question 66

what can chloroquine cause

Answer 66

maculopathy

Question 67

what can amiodarone cause

Answer 67

corneal verticullata

Question 68

what do you never give steroids to

Answer 68

herpetic keratitis