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Advanced Optometry > Mydriatics And Cycloplegics > Flashcards

Mydriatics And Cycloplegics Flashcards

(101 cards)

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1
Q

Autonomic: parasympathetic pathway to the iris

A

Pretectal n. -> EW n. -> ciliary ganglion -> sphincter

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2
Q

Autonomic, sympathetic pathway to the iris

A

Hypothalamus -> ciliospinal center of Budge -> superior cervical ganglion -> dilator muscle

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3
Q

Direct agonist

A

A substance that binds to and fully activates its neuronal receptor
(Drug acts as a NT)

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4
Q

Indirect agonist

A

Potentials the action of the neurotransmitter

Causing NT to bind

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5
Q

Antagonist

A

Any substance that inhibits the activity of the neurotransmitter

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6
Q

An antagonist may bind to __ but not activate it.

A

Bond to a receptor

Affinity but no efficacy

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7
Q

An antagonist may bind to ___ , thereby deactivating it.

A

Neurotransmitter

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8
Q

Cholinergic agents mimic

A

Acetylcholine

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9
Q

Acetylcholinerase

A

Degrades ACh and halts transmission

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10
Q

Muscarinic

A

ACh receptors present in the ciliary body’s and iris

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11
Q

Nicotinic

A

ACh receptors are present in somatic muscle

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12
Q

Muscarinic agonists bind to and activates

A

Cholinergic receptors

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13
Q

Muscarinic agonist drugs cause iris

A

Sphincter contraction leading to pupillary miosis

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14
Q

Muscarinic agonist causes ciliary body

A

Contraction leading to accommodation

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15
Q

Example of a muscarinic agonist

A

Pilocarpine, green cap

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16
Q

Muscarinic antagonist binds to and inhibits

A

Cholinergic receptors (antimuscarinic)

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17
Q

Muscarinic antagonist causes pupil

A

Sphincter inhibition leading to mydryasis

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18
Q

Muscarinic antagonist causes ciliary body

A

Inhibition leading to Cycloplegia

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19
Q

Examples of muscarinic antagonist:

STopACH

A 
Scopolamine 
Tropicamide 
Atropine 
Cyclopentolate 
Homatropine  
(Red cap)
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20
Q

All Mydriatics/ cycloplegic drugs are classified by the FDA as pregnancy category___ meaning….

A

Category C

Potential benefits may warrant use of the drug in pregnant women despite potential risks

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21
Q

CNS side effects caused by antimuscarinic agents vary depending on

A

The ability of the drug to penetrate the blood- brain barrier

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22
Q

Potential CNS side effects of antimuscarinic drugs include

A

Drowsiness, hallucinations, cognitive impairment, and coma

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23
Q

Atropine is the most

A

Potent and longest acting anti cholinergic available for clinical use

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24
Q

Atropine is only used when

A

Total cycloplegia is required

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25
Residual accommodation is
The amount the patient is able to accommodate at the time of maximal cycloplegia
26
Residual accommodation of atropine
Zero diopters
27
What are the clinical uses of atropine?
Refraction, myopia control, amblyopia, uveitis
28
How is atropine used for refraction
Evaluation of esotropia in children less than 6 yrs ole Duration of action too long for routine refraction
29
Atropine in myopia control
Long term low dose therapy inhibit progression
30
Atropine used in amblyopia
Penalization of better seeing eye as alternative to occlusion
31
Atropine used in uveitis
Long term relaxation of ciliary body in severe anterior uveitis
32
Contraindications and precautions of atropine
Allergy Down’s syndrome small children Spastic paralysis or brain damage
33
What happens if atropine is given to spastic paralysis or brain damage
Increased risk of CNS effects and death in pts
34
Systemic overdose symptoms of atropine
Hot as a hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter Fever, blurred vision,, dry skin, flushing, delirium (hallucinations and psychosis)
35
Adverse effects of atropine
Effects from systemic overdose, and IOP elevation
36
Atropine causes open glaucoma pts to experience a transient increase in IOP because
Decreased tension on the scleral spur by the ciliary body will tend to shrink the aqueous drainage passages through the trabecular mesh work The elevation of IOP is NOT due to angle closure
37
Relaxation of the ciliary muscle
Increases IOP
38
Contraction of the ciliary muscle
Decreases IOP
39
IOP effect of cycloplegic agents in normal patients
Minimal and variable | Iop might increase slightly
40
IOP effect of cycloplegic agents in subjects with POAG
IOP will increase following cycloplegia
41
Cyclopentolate is the drug of choice for
Routine cycloplegic refraction | Mostly used in 1%
42
Typical residual accommodation of cyclopentolate is
1.25 D
43
Using cyclopentolate, you will see faster cycloplegia with less residual accommodation in
Lightly pigmented eyes
44
Pigment sequestration
Some drugs when instilled into the eye will reversible bind to melanin
45
What happens if pigment sequestration occurs when a drug is instilled
While bound to melanin the drug is not available to induce any pharmacological effects The drug will have a normal effect after being released fro melanin
46
The net effect of pigment sequestration is
Delayed onset, prolonged duration of action and smaller peak pharmacological effect
47
Pigment sequestration is most pronounced in
Heavily pigmented eyes
48
Side effects of cyclopentolate
Stinging Toxic keratitis with prolonged use Transient elevation in IOP in POAG patients DOSE RELATED CNS EFFECTS: TRANSIENT PSYCHOTIC REACTIONS MAY OCCUR BC IT READILY CROSSES BLODD BRAIN BARRIER
49
Contraindications of cyclopentolate
Increased risk of CNS effects in infants, young children and children with spastic paralysis and brain damage
50
Drug of choice for routine mydriasis
Tropicamide 0.5% and 1% sol.
51
Whats the difference for 0.5% and 1% tropicamide
Equivalent mydriatic effect of 0.5% and 1%, greater cycloplegia with 1% solution
52
Tropicamide is a clinically effective cycloplegia because
It lasts about 30 min
53
Duration of action of tropicamide
Max mydriasis 20-30 min duration 6 hrs | Max cycloplegia 20-45 min duration 6 hrs
54
Contraindications of tropicamide
No reported adverse systemic effects | Extremely safe systemically
55
Side effects of tropicamide
Stinging upon instillation | Transient increase IOP in POAG patients
56
Clinical considerations of homatropine
Weak but prolonged cycloplegic effect and strong mydriatic effect make it suitable for uveitis therapy
57
Duration of action of homatropine
Max mydriasis 40-60 min duration 1-3 days | Max cycloplegia 30-60 min duration 1-3 days
58
Contraindications of homatropine
Same as atropine : | Hypersensitivity, Down’s syndrome
59
Clinical considerations of scopolamine
Not routinely used | Reserved for pts allergic to the others
60
Duration of scopolamine
Very long Max mydriasis 20-30 min duration 3-7 days Max cycloplegia 30-60 min duration 3-7 days
61
Contraindications of scopolamine
CNS effects are more common than other agents because it more easily crosses the blood brain barrier
62
Cycloplegic refraction advantages (3)
More accurate refraction in kids and pts who are unable to cooperate Diagnosis of accommodative esotropia and evaluating strabismus in kids Necessary to diagnose latent hyperopia and pseudomyopia (acc spasm)
63
Cycloplegic refraction disadvantages (4)
Decrease VAs because if spherical aberration Loss of normal ciliary tonus lead as to refraction thats too hyperopic Blurry vision and photophobia Risk of adverse drug effects
64
Cycloplegic refraction can lead to a refraction that is too hyperopic so you will need to
Cut plus from the refraction prior to prescription
65
Tropicamide during cycloplegic refraction | Effectiveness decreases after____. Useful for ____patients.
Effectiveness decreases after 35 min Useful for non amblyopia, non strabismus, myopic, or low hyperopic kids and adults
66
Cyclopentolate for cycloplegic refraction
Drug of choice for cycloplegic refraction
67
Atropine during cycloplegic refraction is used for ____.
Use in esotropia children < 6 years Can reveal additional hyperopia in these children compares to cyclopentolate
68
When will cycloplegic refraction be unreliable
If residual accommodation is >2.00D
69
Using pupillary reactions to asses redisual accommodation
NOT RELIABLE
70
Assessment of residual accommodation during cycloplegic refraction
Subjective push up of accommodative target ‘ Stability of Retinoscopy reflex
71
Adrenergic neurotransmitter
Norepinephrine
72
Transmitter uptake stops
Transmission
73
What type of agonist/anti agonist is phenylephrine
Direct acting agonist
74
Substance that increases the activity of the neurotransmitter
Indirect acting agonist
75
Indirect acting agonist have 2 methods (and examples)
1. Inhibit reputable of norepinephrine (cocaine) | 2. Release of stored presypnaptic norepinephrine (hydroxyamphetamine)
76
Direct alpha-Adrenergic agonist bind to
And activate alpha Adrenergic receptors
77
Direct alpha Adrenergic agonist effect on eye (iris and ciliary body)
Causes stimulation of iris dilator muscle -> mydriasis But no effect on ciliary body or accommodation -> no cycloplegia
78
An example of a direct alpha Adrenergic agonist (mydriasis but no cycloplegia)
Phenylephrine (red cap)
79
Mode of action of indirect alpha - Adrenergic agonist
Causes release of stored norepinephrine from the presypnaptic neuron
80
Mydriatic effect of indirect alpha Adrenergic agonist
Same as direct | Stimulation of iris dilator - mydriasis
81
An example of a indirect alpha Adrenergic agonist
Hydroxyamphetamine (red cap)
82
Phenylephrine cardiovascular effects
Risk of adverse cardiovascular event have been more frequently reported with the 10% strength Therefore 2.5% is recommended for routine use
83
10% phenylephrine solution increases
10% strength produces an increase in rate but not magnitude of mydriasis
84
10% strength of phenylephrine useful for
Breaking posterior Synechia
85
% of phenylephrine used in clinic
2.5%
86
Drug contraindications of phenylephrine
MAO inhibitors Tricyclics antidepressants Reserpine, guanthidine or methyldopa
87
Avoid phenylephrine in patients who
Patients taking systemic antropine Orthostatic hypotension Malignant hypertension Thyrotoxicosis
88
Limit 10% strength phenylephrine to _________ when attempting to break synechia
Limit 10% strength to 1gtt per hour per eye when attempting to break synechia
89
Do not give multiple doses of 2.5% sol for _____
routine dilation | Only recommended in infants and the elderly
90
Phenylephrine systemic side effects
Acute systemic hypertension ventricular arrhythmia, tachycardia, subarachnoid hemorrhage
91
Deaths following phenylephrine
Following use of 10% topical phenylephrine have been reported
92
Ocular side effects of phenylephrine
Mild stinging, pigmented aqueous floaters, little or no effect on IOP
93
Use of 10% phenylephrine for routine dilation
NEVER | Only used for breaking posterior synechia
94
When to use multiple doses of phenylephrine
NEVER for routine pupil dilation If patient isn’t dilating , instill additional drops of tropicamide, not phenylephrine
95
Hydroxyamphetamine clinical considerations
Mydriatic effectiveness equivalent to phenylephrine Role in localizing lesions in Horner syndrome Only commercially available as 1% solution combine with 0.25% tropicamide
96
Localizing lesion in Horner syndrome
Hydroxyamphetamine
97
Duration of action hydroxyamphetamine
Max mydriasis 60 min | Duration 6 hrs
98
Side effects of hydroxyamphetamine
Little to no elevation of IOP in POAG pts Less stinging than phenylephrine
99
Safety difference between hydroxyamphetamine and phenylephrine
May be safer than phenylephrine in high risk pts. However, cardiovascular events have occurred shortly following paremyd instillation
100
Hydroxyamphetamine can be used in the differential diagnosis of
Horner syndrome | Indirect alpha Adrenergic agonist
101
Hydroxyamphetamine causes
Release of norepinephrine from the presypnaptic neuron If presypnaptic neuron is dead -> no dilation in response to hydroxyamphetamine

Advanced Optometry (5 decks)

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