Pharmacology Cycloplegics, Mydriatics, & Mydriolytics (Lecture 15)

Dr. Dunden's Pharmacology Lecture UMSL School of Optometry

6 months old; 3 years; 6 years old (6-3-6 rule)

According to the AOA, children need their first comprehensive eye exam by what age? How many years after that should they go to their next appointment? At what age should children start scheduling comprehensive eye exams annually?

18-64 years old

The AOA recommends what age group to attend a comprehensive exam every 2 years?

65

The AOA recommends an annual exam for anyone over the age of ______.

1. Phenylephrine

2. Tropicamide

What are the 2 main medications we will use daily (especially in clinic) to perform DFEs?

Sphincter pupillae; dilator pupillae; iris

During the normal function of the pupil, what muscle contracts to decrease pupil size? What muscle contracts to increase pupil size? What part of the eye are these muscles contained?

Phenylephrine

What common dilation drop works best on the dilator muscle?

Tropicamide

What common dilation drop works best on the iris sphincter muscle?

a. M3
b. M2/ M3
c. M2/ M3

Identify what receptor(s) target the following cholinergic muscles/glands.

a. Iris Sphincter
b. Ciliary Muscle
c. Lacrimal gland

a. alpha-1
b. β2
c. alpha-2

Identify what receptor(s) target the following adrenergic muscles.

a. Iris Dilator
b. Ciliary muscle
c. Muscle of Müller

1. Scopolamine

2. Tropicamide

3. Atropine

4. Cyclopentolate

5. Homatropine

What are 5 cycloplegics used in optometry?

STACH (STop ACH on muscarinic sites of autonomic fibers & smooth muscles); Paralyze the iris sphincter muscle & the ciliary body

What is the mechanism of action for cycloplegics?

1. Iris sphincter

2. Ciliary body

What are the 2 muscles paralyzed from cycloplegic use?

1. Dilation

2. Cycloplegic refraction

3. Anterior uveitis treatment/ management

What are 3 common uses of cycloplegics?

uveitis

Inflammation of the uveal tract

1. Iritis (iris)

2. Iridocyclitis (Iris/Ciliary Body)

What are 2 specific conditions that can occur with anterior uveitis (include inflamed structures in parentheses)?

1. Trauma (surgery/ accident)

2. Inflammatory Syndromes (RA, Crohn’s)

3. Infection (Sarcoid, Syphillis, TB)

4. Idiopathic (No systemic/ traumatic cause)

What 4 things can cause uveitis in the iris and/ or ciliary body?

Leaking of the blood-aqueous barrier

What causes uveitis cells & flare?

WBCs & protein

What is leaked into the anterior chamber in uveitis?

1. Light sensitivity

2. Pain

What are the 2 most common symptoms of uveitis?

anterior ciliary nerves

When an eye is experiencing uveitis and the iris is contracting in response to light, what part of the eye is becoming agitated, consequently causing light sensitivity & pain?

fibrin

What is up-regulated in uveitis, consequently causing synechiae to form?

anterior

Which type of synechiae is most rare—anterior or posterior?

anterior synechiae

What synechiae forms from the iris sticking to the cornea?

peripheral synechiae

What synechiae forms from the iris sticking to the limbal region around the trabecular meshwork?

posterior synechiae

What synechiae forms from part of the iris muscle adhering to the lens?

cycloplegics

What medication type can be used to aid in uveitis treatment & to break synechiae?

Atropine; Tropicamide

What is the strongest cycloplegic medication? Weakest?

30-40 mins

Maximal mydriasis time for Atropine

60-180 minutes

Maximal cyloplegia time for Atropine

7-10 days; 7-12 days

How long does mydriasis effects last for Atropine? Cycloplegia effects?

Atropine

What is the choice of topical ocular cycloplegics for severe uveitis cases?

Atropine deposits in inflammatory cells in the anterior chamber.

Why must you use more Atropine more frequently in uveitis cases?

1. Immobilize the iris (pain reduction)

2. Stabilize the blood-aqueous barrier (anti-inflammatory)

3. Prevent posterior synechiae formation

What are the 3 benefits of using cycloplegics for uveitis?

Atropine

What cycloplegic is often used for amblyopia treatment?

amblyopia

For individuals under 20 years old, what condition is responsible for more lost vision than ocular disease & trauma?

2%

What percent of the population has amblyopia?

Atropine 1% soln (or ung) qd

What should you specifically Rx to a patient that is doing penalization amblyopia therapy and won’t tolerate patching?

Atropine

What cycloplegic is used in myopia control?

increased

Myopia results from a/an (decreased/increased) axial length.

Atropine 0.1% soln 1 drop qhs

A child needing myopia control management comes into your clinic. What topical ocular drug should you specifically prescribe to this patient to help with this?

Reduced accommodation

What accounts for the mechanism as to why Atropine works in myopia control?

1. Burning/Stinging

2. Allergic contact dermatitis

3. Angle-closure glaucoma (decreased outflow of aqeous)

4. Increased IOP in POAG patients

What are 4 adverse ocular effects of Atropine?

1. Dry mouth & dry eye (dry as a bone)

2. Facial flush & anhydrosis (red as a beet)

3. Increased heart rate

4. Convulsions, Hallucinations, Confusion (Mad as a hatter)

5. Rise in body temp (hot as a hare)

6. Blurred vision & mydriasis (blind as a bat)

7. Urinary Retention & Constipation (full as a flask)

Adverse Systemic Effects of Atropine (7)

1. Children under 3 months of age

2. Patient with known hypersensitivity

3. Angle-closure glaucoma or POAG patients

4. Down’s Syndrome

Contraindications of Atropine (4)

Scopolamine

What cycloplegic is no longer available in the U.S?

Scopolamine

What cycloplegic is found in a transdermal patch to help with motion sickness?

20-30 minutes; 30-60 minutes

Scopolamine time to maximal mydriasis? Maximal Cycloplegia?

3-7 days; 3-7 days

Scopolamine length of mydriasis effects? Cycloplegic effects?

Scopolamine

What cycloplegia medication has similar adverse effects to Atropine but has an increased CNS penetration compared to atropine (more hallucinations, confusion, amnesia, incoherence)?

40-60 minutes; 30-60 minutes

Homatropine time to maximal mydriasis? Maximal Cycloplegia?

1-3 days; 1-6 days

Homatropine length of mydriasis efects? Length of Cycloplegia effects?

It does not have a stable shelf-life.

Why is Homatropine not used often as a cycloplegic drug in clinics?

Homatropine

What cycloplegic is often used for moderate cases of uveitis and can be used for breaking posterior synechiae in combo with other dilation drops?

Homatropine 5% 1 drop QID combined with steroid

A patient comes into your clinic with a moderate case of uveitis. What would you specifically prescribe to this patient?

Homatropine

What cycloplegic has similar side effects to atropine but exhibits decreased odds of developing symptoms due to reduced strength?

Cyclopentolate

What is the most commonly used medication for cycloplegia?

20-45 minutes; 20-45 minutes

Cyclopentolate time to maximal mydriasis? Time to maximal cycloplegia?

1 day; 6-24 hours

Cyclopentolate length of mydriasis effects? Length of cycloplegia effects?

1. Mild uveitis

2. Breaking posterior synechiae

3. “Wet” Cycloplegic Refraction

What are 3 uses of cyclopentolate?

17-13D

How many diopters does the average 6-18 year old accommodate?

1.25 D

What is the average remaining accommodation left for a 6-18 year old after 30 mins with cyclopentolate drop?

True

True/False: Cyclopentolate is a better at cyclopleging than Homatropine.

1. Burning/Stinging on instillation

2. Allergic Rection (rare)

3. Increased IOP in POAG & may precipitate closed angle

What are 3 main adverse effects of cyclopentolate?

M4

Tropicamide has a mild affinity for what receptor?

Tropicamide; 5.37 (less ionized)

What cycloplegic has the best corneal penetration? What pKa value does this cycloplegic have to allow great corneal penetration?

Tropicamide

What is the most commonly used medication for mydriasis?

20-35 minutes; 20-45 minutes

Tropicamide time to maximal mydriasis? Time to maximal cycloplegia?

4-6 hours; 4-6 hours

Tropicamide length of mydriasis effects? Length of cycloplegia effects?

1. DFE

2. Maintainance for chronic uveitis to preventh synechiae

3. “Damp” Refraction

What are 3 main uses for tropicamide?

Tropicamide 1% 2 drops 5-25 minutes apart; 20-35 minutes

How many drops & at what concentration should you give Tropicamide to a patient to perform a “damp” refraction? How long after instillation should you measure refraction?

Tropicamide

What cycloplegic has the lowest affinity to muscarinic receptors?

Tropicamide

What cycloplegic has the least effect on elderly patients due to lack of sympathetic tone?

Down’s Syndrome

Contraindication of Tropicamide (1)

1. Phenylephrine

2. Cocaine

3. Hydroxyamphetamine

Mydriatic medications (3)

Adrenergic neurotransmitter to promote action of the sympathetic pathway

MOA of Mydriatics

Phenylephrine

What is the most common mydriatic?

alpha-1

What receptors does pheynlephrine primarily act on?

2.00D

How many diopters (roughly) are lost at 1 hour after phenylephrine use?

45-60 minutes

Maximal mydriasis effect of Phenylephrine

6-7 hours

Length of mydriasis effect of Phenylephrine

1. Dilation when combined with Tropicamide

2. Breaking posterior synechiae

3. Diagnosing episcleritis verses scleritis

4. Lesion location in Horner’s Syndrome

Uses of Phenylephrine (4)

2.5%

What concentration of Phenylephrine should be used with Tropicamide 1% during a standard dilation?

Wash Out Effect

What effect can occur with all topical ocular medications when one medication is instilled after another ocular medication?

a. 50%
b. 17%
c. 5%

Identify how much of Medication A is washed out when medication B is instilled:

a. 30 seconds after
b. 2 minutes after
c. 5 minutes after

True

True/ False: Order in which you instill topical ocular medications matters.

15 minutes

What period of time between instilling 2 drops do we recommend patients wait?

1. Phenylephrine

2. Tropicamide

When performing a standard dilation procedure, what order should you use tropicamide & phenylephrine?

Phenylephrine 10%

What percent phenylephrine is used to break posterior synechiae?

episcleritis

Inflammation of the conjunctival vessels located superficially

scleritis

Inflammation of the sclera

scleritis

Scleritis vs. Episcleritis: Which condition is accompanied with pain?

scleritis

Scleritis vs. Episcleritis: Which condition is associated with systemic conditions in 50% of cases?

Phenylephrine 10%

What concentration of Phenylephrine is used in the diagnosis of episcleritis?

episcleritis

You suspect your patient may have episcleritis. To ensure it is episcleritis and not scleritis, you administer Phenylephrine 10%. You see the redness of the eye decreased. What condition would you suspect with this observation?

Superior Cervical Ganglion

What landmark represents the splitting point between pre- and post-ganglionic for Horner’s Syndrome?

1. Ptosis

2. Miosis

3. Anhydrosis

What makes up the Horner’s Triad?

less

Central or preganglionic Horner’s Syndrome causes (no/less) norepinephrine release in the synapse, causing a miotic pupil in the dark (anisocoria greater in the dark).

no

Postganglionic Horner’s Syndrome causes (no/less) norepinephrine release in the synapse, causing a miotic pupil in the dark (anisocoria greater in the dark).

hypothalamus; ACh; nicotinic acetylcholine; norepinephrine; dilator; adrenergic; dilator

In the normal functioning of the pupil, the signal starts at the ______________ and the axons synapse at the ciliospinal center of Budge from C8 to T2 in the spinal cord. From there _____ is released and travels the preganglionic pathway to the superior cervical ganglion where it synapses at the ___________ __________ receptor. The superior cervical ganglion releases ______ which travels along the axon to the iris (dilator/ sphincter). This is then released into the synpatic cleft between the nerve and the muscles and binds ___________ receptors on the iris (dilator/sphincter) muscle.

1. Central located between hypothalamus & ciliospinal center of Budge (pre-ganglionic)

2. Between ciliospinal center of Budge & superior cervical ganglion (pre-ganglionic)

3. Between superior cervical ganglion & iris dilator (post-ganglionic)

What are the 3 regions of concern for Horner’s Syndrome?