Cycloplegics, Mydriatics & Miotics

Question 1

Explain how cycloplegics work and their 3 available formulations

Answer 1

POM- Muscarinic antagonist paralyses ciliary muscle via preventing ACh binding

1% Atropine sulphate (Minims) ~ <5yrs, 6-12 days recovery)

0.5-1% cyclopentalate ~ 8-20yrs, 24hr recovery)

0.5-1% tropicamide (Minims)

Multi-dose eye drops ALL contain Benzalchonium Chloride (prevents infection but allergic reactions)

Question 2

Explain the examination, diagnostics and treatment with cycloplegia

Answer 2

Examines refractive error
Diagnoses lazy eye/strabismus
Treats pains, spasms, atony (weak ciliary muscles), stablise uveitis

Question 3

Explain how mydriatics work and their formulations

Answer 3

Dilated pupil blocking iris sphincter contraction

1% Atropine sulphate (Minims) ~ <5yrs, 45-60mins, 7 days recovery)

0.5-1% cyclopentalate ~ 8-20yrs, 30-60mins, 24hrs recovery)

0.5-1% tropicamide (Minims) ~ 15-40mins max, 6-9hrs recovery

Phenylephrine ~ 10-90mins max, 5-24hrs recovery

Question 4

Explain how mydriasis is used to exam, diagnose and treat

Answer 4

Examines fundus (ophthalmoscopy)
Diagnoses DR, glaucoma, IV haemorrhages, higher ICPs, CNS infections
Treats ant.uveitis prevents synechiae, glaucoma from iris/lens diaphragm ant. displacement
Surgery (cataracts)

Question 5

Explain topical uses of cycloplegics

Answer 5

Transient stinging
Blurring
Photophobia
Raised IOP
Conjunctival hyperaemia/oedema
Allergy (rare)

Question 6

Explain systemic side effects and cautions of cycloplegics

Answer 6

Children more than adults
Ataxia
incoherent speech
restlessness/hyperactivity
hallucinations/disorientation
(Normal after 4-6hrs)

Cautious of dark iris needing higher does
Elderly/children under 3 months (amblyopia development)

Question 7

Explain mydriatics topical and systemic uses

Answer 7

Transient stinging, blurred vision, raised IOP, photophobia, AcuteCAG risk

Cardiovascular effects, hypertension. headaches

Caution for darker iris, elderly, diabetics

Question 8

How is muscle contraction produced with Muscarinic receptors?

Answer 8

M3 receptor stimulated signals Gq to increase Ca2+ to contract muscle

Blocked by Muscarinic antagonists (cycloplegia)

Question 9

Explain 6 targets and functions of the oculosympathetic pathway

Answer 9

Iris dilator contracts to dilate pupil
Mullers contracts eyelids
Ciliary epithelium produces aq humour
Trabecular meshwork drainage
Extraocular movement
Canal of Schlemm inner wall

Question 10

Explain Phenylephrine and it’s formulations

Answer 10

3months+/healthy adults only
45-60mil max use, 5-7hrs recovery

2.5% Ph Hydrochloride drops (Minims)
10% Ph Hydrochloride drops (Multi-dose Minims)

Efficacy affected by age/iris colour

Question 11

Explain the topical/systemic uses of phenylephrine

Answer 11

Transient stinging/blurring, allergic conj.
Keratitis, floaters, raised IOP

Systemic hypertension, headaches, subcranial haemorrhages, skin blanching

Question 12

Explain how miotics work and their formulations

Answer 12

Muscarinic agonist
10-30mins max, 6hrs recovery
2% Pilocarpine nitrate (Minims)
Multi dose 1/2/4% pilocarpine hydrochloride

Question 13

Explain the topical/systemic side effects of pilocarpine

Answer 13

Accommodative spasm (up to 2hrs), brow/headaches
pupil block, mitosis at night, lens opacities, conj. infections, RetDet

Cardiovascular increased HR, 30 min vasodilation, bronchoconstriction in lungs, gland secretions

Question 14

Which drugs are POM exemptions for use and supply?

Answer 14

Cyclopentolate HCL
Fusidic acid
Tropicamide

Question 15

What classification are LAs

Answer 15

POM use only

Question 16

What drug can be prescribed for sticky red eye?

Answer 16

Optom: Chloramphenicol (P) ~ bacteria.conj, no CLs/surgery in last 6-12mths

IP: could rx for CL/recent surgery, Azithromycin