CS 3 - Cycloplegic Refraction
Summary of Dosages - Atropine
0.5% ointment bid x2 d for accommodative Esotropia
Summary of Dosages - Tropicamide
1 gtt 1% Drug of choice for routine dilated exam For cycloplegia: 1 gtt 1% q 5 min - refract in 25 minutes
Summary of Dosages - Cyclopentolate
1 gtt 1% q 5 min x2 Drug of choice for routine cycloplegic exam Refract 30 min after instillation Don't use 2% solution-adverse reactions
Atropine
Absorbed through: Cornea Conjunctiva Nasal Mucosa GI Tract
Cyclopentolate Side Effects
Allergic Reaction
Ocular Reactions
Allergic Reaction (especially lids/conjunctiva) Itchy, red, swollen Atropine>Cyclopentolate>Tropicamide (rare)
Tropicamide Side Effects
Allergic Reactions
Atropine Side Effects
Allergic Reactions (contact dermatitis)
Adverse Reactions
Allergy Unpredictable/unexpected reaction Due to previous sensitizing reaction
Tropicamide Side Effects
Angle Closure
Ocular Reactions
Angle-Closure Glaucoma Precipitation of an acute attack Unlikely Observe Precautions: Assess Hx, Assess chamber depth, advise patient of surgery, check IOP before patient leaves
Cyclopentolate Side Effects
Angle-closure glaucoma
Cycloplegic Efficacy
Atropine 100% Scopolamine 92-96% Cyclopentolate 92% Homatropine 60-80% Tropicamide 60-80%
Cyclopentolate Indications
Children
Clinical Procedures - Instillation - Cap Color
Clear=topical anesthetic Red=mydriatic/cycloplegic agent Green=miotic
Proparicaine Adverse Effects
Conjunctival hyperemia
Proparicaine Allergic Reactions
Contact dermatitis (most common) Neomycin>atropine>proparicaine Periocular swelling Erythema Typical rash
Proparicaine Adverse Effects
Corneal Edema
Proparicaine Adverse Effects
Decreased reflex tearing Blocks afferent loop of reflex tearing
Cycloplegia helps Anterior Segment Inflammation by:
Decreases pain due to iridocyclitis Decreases possibility of posterior synechia Tends to restore permeability of inflamed vessels Decreases cells & flare Decreases clogging of angle
Proparicaine Adverse Effects
Delayed corneal healing
Residual Accommodation - Yasuna's Method
Distance correction in phoropter Add +3.00D OU Occlude one eye Target=0.5M at 33cm Reduce + in 0.25D steps to blur Replace +3.00D add in OU again Add + in 0.25D steps to blur Dioptric difference=residual accommodation
Residual Accommodation - Duane's Method
Distance correction in phoropter Add +3.00D OU Occlude target eye Target=0.5M at 33cm Determine near blur point Determine far blur point Dioptric difference=residual accommodation
General Contraindications
Down syndrome (especially with atropine)
Proparicaine
Duration is 10-20 minutes
Atropine
Duration of adequate cycloplegia: 24 hours
Cyclopentolate
Duration of cycloplegia is 1 day
Tropicamide
Duration of cycloplegia is 6 hours
Atropine
Duration of cycloplegia: 7-12 days
Cyclopentolate
Duration of maximum clycloplegia is 2 hours
Tropicamide
Duration of maximum cycloplegia: 15 minutes for 0.5% 40 minutes for 1.0%
Cyclopentolate
Duration of mydriasis is 1 day
Tropicamide
Duration of mydriasis is 6 hours
Atropine
Duration of mydriasis: 7-10 days
Proparicaine Adverse Effects
Endothelial toxicity If transcorneal portal of entry (a perforation)
Proparicaine Adverse Effects
Epithelial toxicity Increases sloughing rate of epithelial cells Slows healing rate (decreases motility)
General Indications for Cycloplegia
Esotropia - to determine accommodative component Suspected latent hyperopia Suspected pseudomyopia Young children Uncooperative/uncommunicative patients Suspected malingering/hysteria Reduced VA with no detectable pathology Anterior segment inflammation
Atropine Indications
Esotropia in children (especially if less than 4 yo) Try 1% cyclopentolate x2 first If residual ET, then use atropine
Atropine Side Effects
Fatal Dose Adult: 100 mg (200 drops of 1%) Children: 10 mg (20 drops of 1%)
Atropine Contraindications
Glaucoma (COAG or NAG) Narrow Angles Hypersensitivity Iris-Fixated IOL Down Syndrome
Cyclopentolate Contraindications
Glaucoma (COAG or NAG) Narrow angles Hypersensitivity Iris-fixated IOL Down syndrome Children with emotional problems History of seizures
Clinical Procedures - Pre-instillation
History VA Pupils Externals Van Herick test Tonometry
Systemic Reactions
Hot as a hare (fever, inability to sweat) Red as a beet (facial flushing, vasodilation) Dry as a bone (dry skin/mouth, inhibition of exocrine glands) Blind as a bat (Cycloplegia, blurred vision) Mad as a wet hen (Irritability/hallucinations, CNS toxicity)
Adverse Reactions
Hyper-susceptibility (intolerance) Quantitatively different response Greater than normal response Due to biologic variation, disease, or other medications
Adverse Reactions
Idiosyncrasy (genetically determined, abnormal reactivity)
Prescribing Myopes
If wet refraction is equal to or more minus than dry refraction: prescribe dry results
Proparicaine Secondary Adverse Effects
Interference with diagnostic tests: Hypofluorescence of fluorecein Variability in Shrimer testing Reduction of microbial recovery in culturing Preclusion of sequential testing Surface keratopathy
Cycloplegic considerations
Iris Color (darkly pigmented=stronger)
General Contraindications
Iris-fixated IOL
General Contraindications
Known Allergy to drug
Tropicamide Contraindications
Known Hypersensitivity Narrow Angle Glaucoma Narrow Angles Iris-fixated IOL
Suspected Pseudomyopia
Low myope on subjective ref. NP symptoms VA fluctuation Acc. hysteresis (blur on looking up) Static more plus than subjective NRA > PRA Acc. amp. low for age
Total Hyperopia
Manifest hyperopia + Latent hyperopia
Cyclopentolate
Maximum cyclopegia after 30-60 minutes
Atropine
Maximum cycloplegia after 1-3 hours
Tropicamide
Maximum cycloplegia after 30-45 minutes
Tropicamide
Maximum mydriasis after 20-35 minutes
Atropine
Maximum mydriasis after 30-40 minutes
Cyclopentolate
Maximum mydriasis after 30-60 minutes
Proparicaine Adverse Effects
Microbial contamination
General Contraindications
Narrow angles History of Narrow Angle Glaucoma
Suspected latent hyperopia
Nearpoint complaints EP at distance Miotic pupils High FCC finding Decreased accommodative amplitude for age Static refraction yields more plus than subjective NRA > +2.50D
Cylcoplegic Disadvantages
Not always complete Not always equal Not always properly timed Alters AC/A Decreases depth of focus Increases aberrations Can make retinoscopy difficult (concentrate on 4 mm in center of pupil) Inconvenience to pt Blurred vision Photophobia Potential adverse effects Toxic Allergic
Proparicaine
Onset is 10-20 seconds
Cycloplegia
Paralysis of accommodation Due to paralysis of the ciliary muscle
Proparicaine
Patient education! Do not rub eyes for next 30 minutes
Cycloplegic considerations
Patients age (younger=greater accommodative amplitude=stronger amplitude)
Atropine
Potent long-acting mydriatic/cycloplegic
Atropine Side Effects
Precipitation of acute-angle closure Glaucoma
Topical Anesthetia - Proparacaine
Prevents stinging Decreases blink rate & tearing (allows prolonged contact time) Roughens corneal epithelium (increases drug penetration)
Proparicaine Adverse Effects
Punctate Keratitis
Cyclopentolate
Rapidly-acting mydriatic/cyclopegic
Tropicamide
Rapidly-acting, short duration, mydriatic/cycloplegic
Proparicaine Adverse Effects
Reduced blink rate Increases evaporation
Tropicamide Side Effects
Safest mydriatic/cycloplegic for patients with: Hypertension Angina Cardiovascular disease
Cycloplegic considerations
Stabismus evaluation (needs greater potency)
Residual Accommodation - Pascal's Method
Static at Distance Static at retinoscope plane Dioptric difference = residual accommodation
Proparicaine Allergic Reactions
Stevens-Johnson Syndrome Skin/mucous membrane disorder Acute phase: fever, URI, mucopurulent conjunctiva Chronic phase: scarring stage
Proparicaine Adverse Effects
Stinging/lacrimation
Cyclopentolate Indications
Suspected latent hyperopia
Cyclopentolate Side Effects
Systemic Reactions Flushing, Fever, Drowsiness (especially in children)
Proparicaine Adverse Effects
Tear film instability Disrupts surface microvilli of epithelial cells, decreases mucous adherence
Cylcoplegic considerations
Therapeutic use (duration proportional to severity of inflammation)
Cycloplegic considerations
Timing (occupational/studying needs=needs short acting)
Atropine Side Effects
Toxic Reactions
Adverse Reactions
Toxicity (Poisoning)
Cyclopentolate Side Effects
Transient IOP elevation
Tropicamide Side Effects
Transient IOP elevation <5mmHg=insignificant clinically
Ocular Reactions
Transient IOP elevation Decreased aqueous outflow, especially occurs in COAG pts, check IOP before patient leaves
Atropine Side Effects
Transient IOP elevation (especially in Chronic Open Angle Glaucoma)
Tropicamide Side Effects
Transient Stinging
Cyclopentolate Side Effects
Transient psychotic reaction Hallucinations Disorientation Restlessness Ataxia Incoherent speech
Cyclopentolate Side Effects
Transient stinging/burning/discomfort
Proparicaine
Use 1 gtt (drop) of 0.5% solution
Tropicamide Side Effects
Visual hallucinations
Tropicamide Indications
Wide dilation (great for BIO)
Facultative Hyperopia
amount of hyperopia that can be compensated for by the patients accommodation
Absolute Hyperopia
amount of hyperopia that cannot be compensated for by the patients accommodation Present if hyperopia is greater than accommodative amplitude
Manifest Hyperopia
amount of hyperopia that may be measured by relaxation of accommodation by plus lenses
Latent Hyperopia
amount of total hyperopia compensated for by the residual tonicity of the ciliary muscle Not equal to facultative hyperopia May be revealed by cycloplegia Cannot be relaxed voluntarily or with plus lenses during dry refraction
