1. Cycloplegic Agents &
Cyclorefraction
Mohammad Arman Bin Aziz
B. Optom
ICO, CU
April 03, 2014

2. What is Cycloplegia?
• It is the paralysis of the ciliary muscle
of the eye, resulting in the loss of
visual accommodation.
• Accommodation is the ability of the
lens to change its refractive power to
view the near objects clearly.
• It is brought about by the contraction
of the ciliary muscles.

3. What are Cycloplegics?
• Agents causing cycloplegia.
• Cycloplegics inhibit the action of the acetylcholine on the
effectors sites innervated by the autonomic nerves.
• They block the muscarinic receptor sites.
• They are also called as anti- muscarinics, cholinergic
antagonists.
• acetylcholine - the acetic acid ester of choline, which is a neurotransmitter
at cholinergic synapses in the central, sympathetic, and parasympathetic
nervous systems; used in the form of the chloride salt as a miotic
cholinergic antagonists - An agent that is antagonistic to the action of
parasympathetic or other cholinergic nerve fibers

4. Cholinergic innervations to eye
• Originate within the Edinger – Westphal nucles located within the
mesencephalon.
• The preganglionic parasympathetic fibers emerge from the
EWN, exit the CNS , through the third cranial nerve and proceed
to ciliary ganglion.
• Synapses takes place with post ganglionic fibers at the ganglion.
The post ganglionic fibers enter the globe through the short
ciliary nerve and terminate on the iris sphincter muscle and the
ciliary body.
• Neurotransmitter in the effectors site is acetylcholine

6. Parasympathetic action in eye
• The pupil size is determined predominantly by the varying degree
of the parasympathetic innervations to the sphincter muscles.
• The contraction of the sphincter muscle cause the constriction of
the pupil.
• The innervation to ciliary body cause contraction of the ciliary
muscle to induce accommodation.

7. Cholinergic receptors
• The cholinergic receptors in human eye have been found in the iris
sphincter and the ciliary body.
• It is of the muscarinic type. Other is nicotinic receptor mainly
found in the skeletal muscles.
• Five sub types of muscarinic receptors(M1-M5)have been
identified.
• The muscarinic agonist action at the receptor constricts the
pupil, contracts the ciliary muscles and in general lower IOP.
• The inhibition of these receptors by the cholinergic antagonist
induce the
pupillary dilatation
paralysis of accommodation

9. Cycloplegic refraction
• It is the procedure to objectively determine the refractive
status of the eye when the accommodative action of the eye
is totally paralyzed.
• Commonly called as cyclorefraction or wet retinoscopy.

10. History...
• Cycloplegic refraction was put in scientific basis by Donders
• It was universally accepted after the publication of the
Donders -
“ Anomalies of accommodation and refraction of the eye” in
1864.

11. Cycloplegic agents
Cholinergic antagonists
Currently five Mydriatic- Cycloplegic cholinergic antagonist are available
for topical use.
 Atropine sulphate
 Homatropine eye drop
 Scopolamine hydrobromide
 Cyclopentolate hydrochloride
 Tropicamide

12. Atropine
• Naturally occurring alkaloid
• First isolated from the belladonna plant(atropa belladona).
• Non selective muscarinic antagonist.
• Most potent mydriatic and cycloplegic agent presently available.
• Depending on concentration mydriatic may last up to 10 days and
cycloplegia for 7 to 12 days.
• Commercially available as the sulphate derivative in 1% solution
or 1% ointment.

13. Mode of action
•Reduce pain from ciliary spasm and to prevent the
formation of posterior synechia from secondary
iridocyclitis
•Increases the blood supply to anterior uvea
•Brings more antibodies in the aqueous humour
•Reduce exudation by decreasing hyperaemia and vascular
permeability

14. Action parameters of atropine
• Cycloplegia begin within 12 to 18 minutes
• Reach to maximum in 106 minutes.
• Accommodation began to retain in 42 hours
• Full accommodation ability usually attained within 8 days.
• Mydriatic effect began in 12 minutes, reach maximum in 26
minutes and reach initial stage in 10 days.

15. Clinical use
Cyclorefraction
• Often used for cycloplegic refraction in young , actively
accommodating children with suspected latent hyperopia or
accommodative esotropia.
• It is not typically used for the routine cycloplegic refraction in
school aged children or adults due to the prolonged paralysis of
accommodation that cause patient handicapped in near vision.
• The use is warranted in the case of esotropia with suspected
accommodative component. This may lead to the permanent
deviation.

16. Other uses
Treatment of myopia
use of atropine may prevent or slow
down the progression of myopia by
avoiding the tension due to
accommodation.
Treatment of amblyopia
used for mild and moderate
amblyopia as and alternative to occlusion.
It is called penalization.

17. Side effects
Ocular side effects
• Direct irritation from the drug itself.
• Allergic contact dermatitis.
• Risk of angle closure glaucoma .
• Elevation of IOP in patients with open angles.

18. Systemic side effects
• Diffuse cutaneous flush.
• Depressed salivation causing dry mouth and increase thirst.
• Fever
• Urinary retention
• Tachycardia
• Excitements, restlessness
• Speech disturbances.
• Ataxia - loss of coordination of the muscles
• Convulsion.

19. Atropine contraindications
•Hypersensitivity to the belladonna alkaloid.
•Have open angle or angle closer glaucoma
•Have tendency towards IOP elevation.

20. 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.

21. Scopolamine
•Non selective antagonist
•Maximum cycloplegic occurs in 40 minutes.
•Last for 90 minutes and by the third day accommodation
come to normal.
•Not a drug of choice.

22. Cyclopentolate
• Introduced in clinical practice in 1951
• Commercially available as 0.5%,1%,and 2% solution.
Clinical use
drug of choice for the routine in nearly all age group, especially
infants and young children.
Faster onset of action and shorter duration of effect.
Equally effective as atropine in the case of older children's.
Full recovery of mydriasis and cycloplegia occur within 24 hours.
Cycloplegia occurs in 30-45 minutes of instillation.
For children under the age of 6 one or two drops of 1% is used
and for children above 6, 0.5% is used.

23. Side effects of cyclopentolate
Ocular side effects
Transient stinging on initial instillation.
Allergic reaction to cyclopentolate are rare and may be unrecognized by
practitioner.
Symptoms of irritation and diffuse redness, facial rash that develop within
minutes to hour of instillation.
Lacrimation , blurred vision are prominent.
Systemic effects
Drowsiness
Ataxia
Disorientation
Disturbance in speech
Restlessness

24. Tropicamide
• Short duration cycloplegic available in 0.5 and 1% solution.
• Cycloplegia in about 30 minutes.
• Recovery occurs within 2-6 hours.
• It is considered inadequate for children cycloplegia.
• Widely used as mydriatic agent.

25. Choice of cycloplegic agents
The choice of drug depends on its
 strength
 duration of action
 duration of effect
 side effects.
Which drug do you choose for cycloplegia?

26. When is cycloplegia ready for refraction?
The completeness of the cycloplegia is determined by assessing
the residual accommodation by push up test.
The mydriasis and cycloplegia do not complete at the same
time.
Unlike homatropine and tropiamide in the case of
cyclopentolate the cycloplegia is completed prior to mydriasis, so
often when there is complete mydriasis the cycloplegia is
considered to be complete for the refraction.

27. Old patients- the need of cyclorefraction decrease
markedly with age
The patient beyond 40 is not expected to have latent
hyperopia.
Young adults- only if latent hyperopia is a problem.
Suspected if asthenopia is complained for near work, but
do not have uncorrected hyperopia and other refractive
and binocular abnormalities.

28. Children
 If a child often preschool is seen with convergent
strabismus, to find if it is associated with
accommodative component.
 Child having the significant esophoria , should also
be undergone cyclorefraction, to find uncorrected
hyperopia.

29. Other indications
• The child uncooperative for the dry retinoscopy.
• If the difference in the refractive error of the eyes is unusually
greater.
• In the case of oblique astigmatism to determine the exact
orientation of power axis.
• If the unusually high astigmatism detected during dry
retinoscopy.
• If the retinoscopy finding is much greater than excepted in the
case of hyperopic patient.

30. Indications for cycloplegic refraction
• Symptom of ‘turning eye’
• Other suspicious symptom (e.g. young child closing or covering one
eye)
• Esotropia
• Significant esophoria
• Low accommodation
• Unstable objective or subjective refraction
• Large discrepancy between objective and subjective results
• Significant anisometropia in young child
• Spasm of the near triad [pickwell]

31. 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.

32. References
• Pickwell’s binocular vision
• Internet