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Cyclo Refraction.dider
1. Syed Mohammed Didarul Alam
B.Sc in optometry (B.Optom)
Faculty of Medicine
Institute of Community
Ophthalmology
2. What is Cycloplegia?
• Cycloplegia means paralysis of the ciliary
muscle which inhibits the accommodative
power of the eye by blocking the action of the
ciliary muscle.
• The best way to obtain paralysis of
accommodation is to use cycloplegic drugs.
3. Principle of cycloplegic refraction
• Determination of total refractive error during
temporary paralysis of ciliary muscles as an
instillation of cycloplegic drugs & it is objective
methods which is also known as wet retinoscopy
4. History
• Donders – 1864 “ Anomalies of accommodation and
refraction of the eye”
• cyclopegics have been 1st used since middle
of the 19th century to relax the accomodaton
for the assesments of refractive error
• In 1950 atropine sulfate & homatropine
hydrobromide are the cycloplegics choice.
6. Relax accomodation & inhibits the accommodative power
of the eye
Inhibits the cholinergic stimulation of iris sphincter and
ciliary muscle
Block the action of acetylcholine in CM receptors
( muscarinic)
Cycloplegic drugs ( anticholenrgic)
8. Cholinergic receptors
• found in the iris sphincter and
the ciliary body.
• It is of the muscarinic type also
found in the skeletal muscles.
• Five sub types of muscarinic
receptors(M1-M5)
• The muscarinic agonist action
at the receptor constricts the
pupil & contracts the ciliary
muscles.
• The inhibition causes pupillary
dilatation & paralysis of
accommodation
9. Indication for cycloplegic refraction
• Pediatric age group
• Suspect and/or manifest strabismus
(especially esotropia)
• Accommodative esotropia
• Intermittent esotropia
• Infantile esotropia
• Excessive accomodation
• Suspected latent hyperopia
• Suspected pseudomyopia
• High Hypermetropia
10. Indication for cycloplegic refraction
• Significant anisometropia
• Suspected accomodative anomalies
• Uncooperative/noncommunicative patients
• Variable and inconsistent end point of refraction
• Amblyopic children
• Psychiatric patient
• Asthenopia
• Cerebral palsy
• Suspected malingering and hysterical patients
12. Gauri S Shrestha, M.Optom, FIACLE
Selection and use of specific cycloplegic
agents
Agent [C%] Dosage Max
cycloplegic-
effect
Duration
of effect
Residual
accom
Atropine
sulfate
Homatrop
ine
0.5%,1%
2%
1D TID 3
days
1D TID
3-6 hrs
1hrs
2-3 weeks
1-3days
Negligible
Negligible
Scopolami
ne HBR
0.25% 1D TID 60 mins 1-3 days Negligible
Cyclopent
olate HCL
0.5%(birth-
3yr),
1%(>3yrs)
1D TID 30-45
mins
24 hrs minimal
Tropicami
de HCL
0.5%, 1% 1D TID 20-30
mins
4-8 hrs moderate
13. Atropinization
• Natural alkaloid (Atropa belladonna)
• Commercially available as the sulphate
derivative in 1% solution or 1% ointment
• 1 Dosage TID- 3 days
• Max cycloplegic effect within 3-6 hours
• Recovery 2-3 weeks
14. Mode of action
• Act as antagonist of the
muscarinic acetylcholine
receptors
• Dampens the action of the
parasympathetic nervous
system
• Resulting cycloplegic &
mydriatics effec
15. Clinical use
• Excessive accomodating children
• suspected latent hyperopia
• accommodative esotropia
• Treatment of amblyopia-
• Treament of uveitis,keratitis
16. Atropine may lead to complications
• Fever
• Dry mouth
• Decrease Sweating
• Decrease bronchial
secretions
• Allergic reactions
of the eyelids and
conjunctiva.
• Elevation of IOP
• tachycardia
• Convulsions &
• even death
18. Homatropine
•One tenth as potent as atropine.
•Shorter duration of mydriasis and
cycloplegia.
•It is not the drug of choice for the
cycloplegic refraction because of its
prolonged mydriatic and cycloplegic
action.
19. Side Effect
• include incoherent Speech
• Hallucinations
• disorientation
• psychosis &
• visual disturbances.
20. cyclopentolate
• cyclopentolate 0.5% are used as opposed to 1% for
infants
• This is because drug absorption through the
conjunctival epithelium and skin is more rapid in infants
compared to adults due to immature metabolic enzyme
systems in neonates
• Faster onset of action and shorter duration of effect.
• Cycloplegia occurs in 30-45 minutes of instillation
• 1 drop & repeated within 5 min
• 0.75D will be subtracted from retinosopic findings
21. Side Effect
Occular
• Lacrimation
• blurred vision
• Hallucinations
Systemic
o Ataxia
o Disorientation
o Disturbance in
speech
o Restlessness
22. Procedure
• Reduce the room illumination
• The patient asked to look at the retinoscopic
light
• Then neutralize the primary meridians &
neutralize the Refractive Error
23. What does our practice say?
• Advise atropine cycloplegic refraction invariably in
the children younger than 3 years
• Advise atropine cycloplegic refraction in esotropic
children (accommodative type) up to 4 years
• After 4 years, advise cyclopentolate cycloplegic
refraction up 25-30 years
• Above 30 years, check amplitude and lag of
accommodation, then advise cycloplegic refraction
24. – If full cycloplegia has been achieved then normal
tonus of the CM will also relaxed & it will reach
3/4D & due to CM tonus 1D should subtracted
– In Myopia it is not necessary to subtracted but in
hyperopia it is necessary.
25. Spectacle prescribing
• Prescribing spectacle from cycloplegic finding
is an art rather precise science
• How to prescribe spectacle?
– Concept of emmetropization is necessary
– Esotropic children younger than 4 years, full
refractive correction(maximum plus) is prescribed
– With older children, amount of plus can be reduced
till fusion is maintained
26. Post mydriatic treatment (PMT)
•Assessment of the finding of cyclorefraction by
subjective means after the effect of
cycloplegia is eliminated.
•If atropine is used ciliary tonus should be
subtracted.
•Not necessary in the case of cyclopentolate.
27. References
• Primary Care Optometry
• Clinical Procedure Of Optometry
• Clinical Ophthalmology- Jack J Kanski
• American Academy of Optometry (AAO)
• Pediatric Ophthalmology & Strabismus - AOA
• Internet
