Mydriatics and Cycloplegics

Question 1

What is the neurotransmitter for the parasympathetic nervous system?

Answer 1

Achetylcholine

Question 2

True or False: Muscarinic (M) receptors are associated with the terminal organs of postganglionic nerves in the cholinergic systems

Answer 2

True

Question 3

Where else are Nicotinic (N) receptors found besides on the postganglionics of the ANS?

Answer 3

Nicotinic receptors are also found in the terminal receptors of the somatic nervous system.

Question 4

True or False: Norepinephrine (NE) is the neurotransmitter used in the sympathetic adrenergic system and its target receptors are alpha (a) and beta (B).

Answer 4

True.

Question 5

What are the adrenergic ocular effects?

Answer 5

1. Mydriasis (radial iris muscle contraction)
2. Increase interpalpebral aperture (Müeller’s smooth muscle)
3. Modulate aqueous generation by the ciliary body
4. Suppress accommodation thru receptors in the trabeculum & Schlemm’s canal

Question 6

What are the factors leading to reduced sensitivity of dilating drugs?

Answer 6

1. Age-related miosis
2. Unstable diabetes
3. Post-op pupils
4. Posterior synechiae(where the iris adheres to the lens: i.e bc of glaucoma or diabetes)
5. Dark irides
6. Pseudoexfoliation Syndrome

Question 7

How fast does iatrogenic angle closure usually generally occur?

Answer 7

4-8 hours post instillation.

Question 8

What are the contraindications of dilation?

Answer 8

• Iris supported intraocular lens
• Subluxated lens or intraocular lens
• Extremely narrow angle*
• Angle closure history without peripheral iridotomy (PI)

Question 9

Name the two Sympathomimetic Amines sympathtic mydriatics.

Answer 9

• Phenylephrine

- Hydroxyamphetamine (PAREMYD®)

Question 10

Paremyd is composed of which two drug combinations?

Answer 10

0.25% tropicamide and 1% hyroxyamphetamine

Question 11

Why is paremyd better suited for pts with shallow angles as compared to the drug combinations of Phenlylephrine and Tropicmide.

Answer 11

PYREMYD is better suited for shallow angle pts because it has faster recovery.

Question 12

T/F: The adverse affects of PYREMYD include hypertension and tachycardia.

Answer 12

True

Question 13

If you have an anesthetic, phenylephrine and tropicmide, in which order should you use the drops and why?

Answer 13

Use order: anesthetic (enhance absorption by breaking tight junctions): phenylephrine (vasoconstrict and dilate which reduces entrance of drug to systemic circulation) then tropicamide (to dilate).

Question 14

Which cycloplygic drop/drug is used most commonly?

Answer 14

Tropicmide (is an anti-cholenergic drug, has moderate selectivity for M4 receptors, 20-35 minutes to action and l effects last upto 6hrs)

Question 15

What are the ocular adverse reactions of anti-cholenergics?

Answer 15

↑ IOP, angle closure risk, allergy

Question 16

What are the systemic adverse reactions of anti-cholenergics?

Answer 16

ABCDs
Aneroxia
Blur
Constipation &
Confusion
Dryness
Sedation &
Stasis of urine

Question 17

What are the CNS adverse reactions of anti-cholenergics?

Answer 17

↓ Parkinson tremor, ↓ HR