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Optometry Clinical Skills 3 > Cycloplegic refraction lecture > Flashcards

Cycloplegic refraction lecture Flashcards

1
Q

What is min. pre-installation workup?

A

Hx, VA, Pupils, Slit lamp, Van Herick angles, Tonometry

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2
Q

Color of Cap indicates

A 
Clear = anesthetic (Proparacaine/Altacaine)
red = mydriatic/cycloplegic (Tropicamide,phenylephrine,cyclo)
green = miotic
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3
Q

Why punctal occlude?

A

Prevent system absorption

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4
Q

Vasovagal syncope

A

transient, temporary loss of consciousness and posture
Action: keep pt safe, lower head and raise feet, open alcohol pad to smell, allow pt to rest 15-30 min
“if face is red, raise head. if face is pale, raise tail (feet)”

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5
Q

Standard Dilation drops?

A

1 drop 0.5% proparacaine/altacaine
1 drop 1% tropicamide
1 drop 2.5% phenylephrine

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6
Q

Anesthetics

A

prevents generation and conduction of nerve impulses by binding to specific receptors that control gating of Na channels

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7
Q

Anesthetic classification

A

Esters: cocaine, proparacaine, tetracaine, benzocaine

Amides: lidocaine and bupivacaine

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8
Q

Topical Anesthetics (Use, Side effects/adverse effects, Contraindications,)

A

Proparacaine or tetracaine
1 gtt 0.5% sol.

Duration: 10-20 min

USE: prevents sting, dec. blink rate & tearing, inc. drug penetration

Side effects: burning/stinging/lacrimation, punctate keratitis, corneal edema, conj. hyperemia, delayed corneal healing, blurred vision, tear film instability (dec. tbut, dec. mucous adherence), dec. reflex tearing, epithelial toxicity (sloughing inc.), endothelial toxicity, microbial contamination

2nd adverse effects:
hypofluorescence of fluorescein, variability in schirmer test, reduction of microbial recovery in culturing, surface keratopathy

contraindication: hypersensitivity

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9
Q

Cycloplegia Vs. Mydriasis

A

Cycloplegia: paralysis of ciliary muscle by anti-muscarinics

Mydriasis: dilation of pupil through dilator contraction by adrenergic agonists OR sphincter relaction by muscarinic antagonists.

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10
Q

Iris dilator and Iris sphincter

A

Iris dilator: sympathetic imput - pupil dilates when contracted (mydriasis)

Iris sphincter - parasympathetic input - cholinergic muscarinic (mydriasis and cycloplegia)

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11
Q

Mydriatics dilation (phenylephrine)

A

Stimulate adrenergic division of ans (bind and activcate alpha receptors)

sympathomimetics: increase pupil size - contracts iris dilator, widen palpebral fissure, constriction of blood vessels ‘blanching’, spares accommodation

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12
Q

Cycloplegia dilation (tropicamide)

A

inhibit cholinergic division of ans (block muscarinic receptors on ciliary muscle and prevent acetylcholine)

parasympatholytics: inhibit accommodation - ciliary muscle paralysis

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13
Q

Mydriatics indications

A

occurs within minutes and lasts 4-6 hours

indications: floaters, flashing lights, dec. va, unexplained vf, unknown etiology ocular pain, post trauma to eye, hx diabete, hx ret. disease, pupil defect or miosis, media opacities

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14
Q

mydriatic effects - age

A

older patients have release of pigment granules from iris neuro-epithelium after phenyelphrine
elderly - less mydriasis with phenyl and hydroxyamphetamine is less effective

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15
Q

Alpha agonists

A

visine and clear eyes

  • causes rebound hyperemia and inc. conj injection
  • conj. blanching “get the red out”
  • more drug is required for same effect
  • use caution in pt: taking inhibitors, tricyclic antidepressants, antihypertensive medications
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16
Q

phenylephrine (2.5%)

A 
direct-acting alpha-adrenergic agonist
- dilation and conj. vasoconstriction/blanching hyperemia
-spares accommodation
-pupil will constrict bright light
max dilation = 45-60 min
duration of dilation = 4-6 hrs
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17
Q

phenyl precautions, contraindications, side effects

A

systemic htn; dm1; heart disease; adv arteriosclerosis

contraindications: narrow angles, hypersensitivity, iris IOL, or pt taking MAO inhibitors, tricyclic antidepressants, reserpine, guanidine, methyldopa

side effects: ocular - lacrimation, keratitis, pigmented aqueous floaters, rebound miosis, rebound conj. congestion
systemic - systemic htn, occipital h/a, subarachnoid hemorrhage, ventricular arrhythmia, tachycardia, reflex bradycardia, blanching of skin - due to vasoconstriction

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18
Q

Type of Cycloplegia drugs

A
  • Atropine (longest recovery mydriasis and cycloplegia)
  • Scopolamine
  • homatropine
  • cyclopentolate
  • tropicamide (shortest recovery mydriasis 6hrs and cycloplegia 6hrs)
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19
Q

indications for cycloplegia

A
  1. esotropia - determine accom. component
  2. suspected latent hyperopia
  3. suspected pseudomyopia
  4. young children
  5. inconsistent subj. responses
  6. malingerers/unreliable pts
  7. hysterical pts / uncommunicative pxs
  8. pt do not correct 20/20 - no patho
  9. high heterophoria
  10. accommodative asthenopic symp.
  11. ant. segment inflammation treatment (dec. pain due to iridocyclitis, stabilize/restore blood-aqueous barrier, dec. possibility of post. synechiae)
20
Q

cycloplegic effects

A

2 drops of tropicamide gives reasonable cyclo (less than 2D resid. accommodation)

cyclopentolate: residual accommodation 1.5 D

21
Q

cycloplegic side effects

A

ocular: blurred vision, loss of near vision, photophobia, mydriasis, dry eye, transient IOP elevation, acute angle closure glaucoma
systemic: fever/unable to sweat, facial flushing, tachycardia, dry mucous membranes, CNS toxicity, delirium

22
Q

cycloplegia disadvantages and adverse reactions

A

not always complete/equal, alters AC/A, decreased depth of focus, photophoibia, inconvenience to pt

toxicity, idiosyncrasy, hypersusceptibility (intolerance), allergy (unpredictable, red,itchy, swollen)

23
Q

Atropine (usually 0.5% ointment bid x 2 d)

A
  • use min. amt needed
  • 1.0% sol. for ET BID 3 days before exam
  • duration of cyclo = 24 hours
  • contraindications = glaucoma, narrow angles, hypersensitivity, iris-fixed IOL, down syndrome
  • SE = acute angle closure, allergic rxn, toxic rxn (dry mouth, facial flushing, fever, tachycardia, irritability, delirium)
24
Q

cyclopentolate (1 gtt 1% q 5 min x 2; drug of choice for routine cyclo exam)

A
  • usual usage 1 gtt 1% q 5 min x 2
  • max cyclo: 30-60 min
  • max cyclo: 2 hrs
  • duration of cyclo: 1 day
25
Q

Tropicamide (1 gtt 1%; drug of choice for routine dilated exam)

A
  • rapidly-acting, short duration mydriatic/cycloplegic
  • 1 gtt 1% x 1 for dilation
    max cyclo = after 30-45 min
    duration of cyclo = 6 hrs
    max mydriasis = after 20 - 35 min
    duration fo mydriasis = 6 hrs
26
Q

Okay to dilate with narrow angles?

A

Any medication with anticholinergic properties should be used in caution with narrow angles.
should acute angle-closure attack occur, suspected medication must be d/c

27
Q

acute angle closure glaucoma

A

restriction in aqueous flow creates excessive pressure in post. chamber, which bows peripheral iris forward and closes the angle

greatest risk: asian ethnicity, advanced age, female, hyperopia, pos. family hx, narrow iridocorneal angle, and shallow ant. chamber depther

28
Q

does IOP change after std. dilation?

A

yes, about 96% pt has change in IOP less than 5 mmHg and 4% has change in IOP greater than 5 mmHg

29
Q

cycloplegic refractive techniques

A
  1. measure residual accommodation (min. res acc. = 2D)
  2. perform retinoscopy (central 4mm)
  3. subj refraction
30
Q

Measuring residual accommodation

A
  1. Pascal’s method: diff. between static at D and retinoscope plane
  2. Duane’s method: add +3 ou and determin near blur point and far blur point (monocular, target 0.5 M at 33cm)
  3. Yasuna’s Method: add +3 ou over rx and add 0.25 to blur and reduce 0.25 to blur (monocular, target 0.5 M at 33cm)
31
Q

Total Hyperopia

A

manifest (amt measured by relaxation of accommodation with plus lenses AKA dry refraction) + latent (amt hyperopia not readily relaxed AKA wet reffraction)

32
Q

Types of hyperopia

A

Absolute: cannot be compensated for by accommodation

facultative: can be overcome by accommodation

33
Q

What is total hyperopia? +3 D sphere on ret and +2 D subj refraction. patient has 12 D AA

A

Manifest hyperopia: 2 D
facultative hyperopia = 2 D
absolute hyperopia = 0
latent hyperopia = 1 D

Total = 3 D

34
Q

egger’s rule?

A 
20/50 = -1.00
20/100 = -2.00
35
Q

Average amplitude accommodation?

A

18.5 - 0.3 * age

36
Q

min. amplitude accommodation?

A

15 - 0.25 * age

37
Q

Myopia management - children

A
  • 16 males/15 females age of cessation
  • progression rates 0.42 males/0.48 females
  • RX based on near phoria = expected 3-5 XP; if EP = consider BF or removing for near
38
Q

Myopia management - YA

A
  • Either stabilizes, slow progression, continuation, or acceleration (least prevalent; seen with corneal steepening)
  • RX least minus with best VA (watch for EP, consider CL)
39
Q

Myopia management - Late adults

A
  • myopia stable, change +-.50 per 10 years
  • cause: nuclear cataracts
  • RX least minus with best VA
40
Q

Myopic cycloplegic RX

A

IF wet is = or more minus than dry, give DRY RX

If wet is more +, RTC for post-cuclo exam

41
Q

Challenges of hyperopia

A
  • undetected b/c accommodation
  • excessive amt of accommodation can result in ET
  • prolonged near work can result in eyestrain
42
Q

Uncorrected Hyperope

A

untreated eyter will result in suppression and then amblyopia

43
Q

Hyperopia management

A

depends on 3 factors:

  1. age
  2. amt of hyperopia
  3. pt complaints

cycloplegic refraction should be done
wet - dry = latent hyperopia
RTC if latent exists

44
Q

Hyperope Rule of thumb for RX

A 
Amt of latency/Add to dry
0 to +0.50/ 0D
\+0.75 to +1.00/ +0.25 D
\+1.25 to +2.00/+0.50 D
above +2.00/ 0.25*latent amt
45
Q

Hyperope consideration

A

Consider near RX for hyperopes

  • reading spec
  • bifocals (large segmemt)
  • recheck 2-4 months
  • repeat dry refraction
46
Q

What to do at end of cyclo exam?

A
  • Pt ed. on blur/driving/photphobia
  • dispense sunglasses (paper ones if needed)
  • don’t use miotic drops

Optometry Clinical Skills 3 (8 decks)

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