Syed Mohammed Didarul Alam

B.Sc in optometry (B.Optom)Faculty of Medicine

Institute of Community Ophthalmology

University of Chittagong

CYCLOPLEGIC REFRACTION

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.

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

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.

Cycloplegic drugs

• Atropine sulphate• Homatropine• Tropicamide• Cyclopentolate HCl• Scopolamine HBr

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)

Parasympathetic action in eye

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

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

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

Contraindication

• Shallow anterior chamber with close angle

• Narrow angle glaucoma• Systemic anti-cholenergic

drugs receiver

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 sulfateHomatropine

0.5%,1%

2%

1D TID 3 days1D TID

3-6 hrs

1hrs

2-3 weeks

1-3days

Negligible

Negligible

Scopolamine HBR

0.25% 1D TID 60 mins 1-3 days Negligible

Cyclopentolate HCL

0.5%(birth- 3yr), 1%(>3yrs)

1D TID 30-45 mins

24 hrs minimal

Tropicamide HCL

0.5%, 1% 1D TID 20-30 mins

4-8 hrs moderate

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

Mode of action

• Act as antagonist of the muscarinic acetylcholine receptors

• Dampens the action of the parasympathetic nervous system

• Resulting cycloplegic & mydriatics effec

Clinical use

• Excessive accomodating children• suspected latent hyperopia• accommodative esotropia• Treatment of amblyopia- • Treament of uveitis,keratitis

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

Contraindication

• Hypersensitivity• angle closer glaucoma

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.

Side Effect

• include incoherent Speech• Hallucinations• disorientation• psychosis &• visual disturbances.

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

Side Effect

Occular• Lacrimation • blurred vision• Hallucinations

Systemico Ataxia o Disorientationo Disturbance in

speech o Restlessness

Procedure

• Reduce the room illumination• The patient asked to look at the retinoscopic

light• Then neutralize the primary meridians &

neutralize the Refractive Error

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

– 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.

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

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.

References

• Primary Care Optometry• Clinical Procedure Of Optometry• Clinical Ophthalmology- Jack J Kanski• American Academy of Optometry (AAO)• Pediatric Ophthalmology & Strabismus - AOA• Internet

THANK YOU

Tajmim Ara Keya Accomodative Esotropia

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