9. Mydriatics, Cycloplegics & Mitosis 2 Flashcards
Mechanism of action of all cycloplegic drugs? And they act on?
Mechanism: Antimuscarinics
Act on: Ciliary muscle and iris sphincter- Relax ciliary muscle that will relax the accommodation.
Most common choice of cycloplegic drug in optometry is?
Cyclopentolate
Conc used for cyclopentolate?
0.5% and 1%- 1% used for children
What preservative is used in cyclopentolate bottles?
How to identify if solution has degraded?
Benzalkonium chloride
When solution degrades it turns brown.
Clinical use of cycloplegics?
Cycloplegic refraction
Typical dose of cyclopentolate used for 3-5 year old’s vs children over 12?
3-5: 1% with 5 minute intervals inbetween.
Over 12: 0.5% used.
Her conc in age 3-5 because they have strong accommodation that needs to be relaxed.
Pharmacokinetics of cyclopentolate
Onset: 30 minutes
Duration: Gradual recovery over 24 hours
How to avoid CNS effects?
Occlude nasal punctata by PXs after installing drops in
ADRs with cyclopentolate?
- CNS effect
- Disorientation
- Hallucination
- Rapid speech
- Uncontrolled limb movement
- Collapse
This effects are self-limiting.
Why is tropicamide preferred by Px’s?
Better recovery from blurred vision.
Tropicamide is not the choice of drug used for cycloplegic refraction, why?
It is unlikely to produce sufficient cycloplegia in children- it does not get rid of enough amplitude of accommodation.
Dose, onset and duration of tropicamide
Dose: 1% with 5min intervals
Onset: 30mins
Duration: 6 hours
Is homatropine available readily?
Ordered specifically, not readily avaiable.
Extra qualification needed to use this drug.
Dose, onset and duration of Homatropine?
Dose: 1%
Onset: 30-60mins
Duration: 1-2 days
Slow recovery, long dilation
What is residual accommodation?
Amount of accommodation left after cyclopic drug is put in the eye.
