Cycloplegic refraction ppt

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1. Cycloplegic Refraction MEHEDI HASAN

2. Cycloplegic Refraction Cycloplegic refraction was first put in scientific basis by Donders, and universally accepted after the publication of Donders - “ Anomalies of accommodation and refraction of the eye” in 1864. What is meant by Cycloplegic Refraction: ● Cyclo = ciliary, Plegic = Paralysis or palsy… Cycloplegic = Ciliary Paralysis. ● Uses Anti-cholinergic agents and blocks response of ciliary muscle and iris sphincter muscle which causes accommodation of the lens relaxed and mydriasis . A cycloplegic refraction is a procedure used to determine a person’s complete refractive error by temporarily paralyzing the ciliary body using cycloplegic eye drops . During this test the accommodation of lens is fully relaxed .

3. Cycloplegic Refraction Cycloplegia : It is a condition when the accommodation is fully relaxed and the retinoscopy findings for both distance and near remain same. 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 . Most often when there is complete mydriasis the cycloplegia is considered to be complete for the refraction . And the refraction may be unnecessarily delayed or additional drug may be used unnecessarily.

4. Cycloplegic Refraction 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- muscarinic , cholinergic antagonists.

5. Cycloplegic Refraction Cholinergic receptors : The cholinergic receptors in human eye have been found in the iris sphincter and the ciliary body, it is one of the muscarinic type. Five sub types of muscarinic receptors(M1-M5)have been identified. The muscarinic agonist takes action at the receptor which 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 and paralysis of accommodation.

6. Cycloplegic Refraction Cycloplegic agents : 1. Atropine Sulfate . 2. Homatropine hydrobromide . 3. Cyclopentolate hydrochloride . 4. Tropicamide .

7. Cycloplegic Refraction Atropine • Natural Alkaloid . • First isolated from the belladonna plant ( Atropa belladonna). • Commercially available as in 1% eye drop or 1% ointment. • Onset of action is slow ( 3 to 6 hours to reach maximum) but duration of action lasts up to 2 to 3 weeks . •Applied 3 times daily for 3 days (both ointment and drop) and the test is done on 4 th day.

8. Cycloplegic Refraction Side effects : ●Direct irritation from the drug itself. ● Risk of angle closure glaucoma. • Dry mouth and increase thirst. • Fever • Urinary retention • Excitements, restlessness • Speech disturbances. • Ataxia • Convulsion

9. Cycloplegic Refraction Death of six reported cases have occurred in children 3 years of age or younger. Atropine contraindications: • Hypersensitivity to the belladonna alkaloid. • Have open angle or angle closer glaucoma • Have tendency towards IOP elevation. •CP and Epilepsy patients. Etc.

10. Cycloplegic Refraction Homatropine • One tenth as potent as atropine. • Shorter duration of mydriasis and cycloplegia than atropine. Duration of action lasts up to 3 to 5 days. • It is not the drug of choice for the cycloplegic refraction most often.

11. Cycloplegic Refraction Cyclopentolate • Mostly used. • Commercially available as 0.5%,1%,and 2% solution. • Drug of choice for the routine in nearly all age group, especially young children (5-14 years). • Faster onset of action and shorter duration of effect. • Cycloplegia occurs in 45-90 minutes of instillation and duration of action lasts for 24 to 48 hours.

12. Cycloplegic Refraction Side effects of cyclopentolate: • Burning sensation on initial instillation. • Allergic reaction to cyclopentolate are rare and may be seemed. • Symptoms of irritation and diffuse redness , facial rash that develops within minutes to hour of instillation. • Lacrimation and blurred vision. • Disturbance in speech . • Restlessness.

13. Cycloplegic Refraction Tropicamide It is considered inadequate for children cycloplegia. ● Widely used as mydriatic agent. ● Available in 0.5 and 1% solution. ● Cycloplegia in about 30 minutes. ● Duration of action is up to 2-6 hours.

14. Cycloplegic Refraction Side effects 1.Blurred Vision 2.Photophobia 3.Eye irritation 4.Dry mouth 5.Skin rash 6.Upset stomach or throwing up

15. Cycloplegic Refraction Why would anyone need a cycloplegic refraction / Indications : Cycloplegic refraction is usually performed on children as they can accommodate too much. Also children tend to change focus at a closer object and unable to maintain their focusing when it is needed to look at a far distance during examination.

16. Cycloplegic Refraction Other indications : ● Latent Hyperopia & Hyperopia ● Strabismus & Nystagmus. ●Young children who have symptoms but not significant refractive error. ●Non-cooperative patients. ●Amblyopic children. ●Suspected malingering & young children. ● Pseudo myopia , Etc.

17. Cycloplegic Refraction Post Mydriatic Test ( PMT ) Assessment of the finding of cyclo-refraction by subjective means after the effect of cycloplegia is eliminated. In case of cyclopentolate this test is usually done after 3 days and 1 month later on in case of atropine. Note : If the patient is Hypermetropic , Give the most PLUS(+) power possible without reducing VA.

18. Cycloplegic Refraction What does our practice say : ●Advise atropine for cycloplegic refraction under 3 to 4 years of age. ●Advise cyclopentolate for above 5 to 15 years of age. ●In objective refraction, we will need to reduce extra more +1.00 DSP in case of atropine and extra more +0.50 DSP in case of cyclopentolate. ● In case of esotropia , give the full correction in hyperopia and under correction could be given in myopia . ●In case of exotropia , give the full correction in myopia and under correction could be given in hyperopia.

19. Cycloplegic Refraction References ●American Academy of Optometry (AAO) ●Recent Journal of Optometry Articles from ELSEVIER ●Clinical ophthalmology - Jack J Kanski ●Pediatric Ophthalmology & Strabismus - AOA ●Internet.

20. Thanks All.