Cyclo Refraction.dider

cyclorefraction

1. Syed Mohammed Didarul Alam B.Sc in optometry ( B.Optom ) Faculty of Medicine Institute of Community Ophthalmology University of Chittagong cycloplegic refraction

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 1 st used since middle of the 19 th century to relax the accomodaton for the assesments of refractive error In 1950 atropine sulfate & homatropine hydrobromide are the cycloplegics choice.

5. Cycloplegic drugs Atropine sulphate Homatropine Tropicamide Cyclopentolate HCl Scopolamine HBr

6. Parasympathetic action in eye

7. 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

8. 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

9. 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

10. Contraindication Shallow anterior chamber with close angle Narrow angle glaucoma Systemic anti- cholenergic drugs receiver

11. 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 Homatropine 0.5%,1% 2% 1D TID 3 days 1D 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

12. 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

13. Mode of action Act as antagonist of the muscarinic acetylcholine receptors Dampens the action of the parasympathetic nervous system Resulting cycloplegic & mydriatics effec

14. Clinical use Excessive accomodating children suspected latent hyperopia accommodative esotropia Treatment of amblyopia - Treament of uveitis,keratitis

15. 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

16. Contraindication Hypersensitivity angle closer glaucoma

17. 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.

18. Side Effect include incoherent Speech Hallucinations disorientation psychosis & visual disturbances.

19. 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

20. Side Effect Occular Lacrimation blurred vision Hallucinations Systemic Ataxia Disorientation Disturbance in speech Restlessness

21. Procedure Reduce the room illumination The patient asked to look at the retinoscopic light Then neutralize the primary meridians & neutralize the Refractive Error

22. 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

23. 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.

24. 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

25. 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 .

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

27. THANK YOU

28. Tajmim Ara Keya Accomodative Esotropia Next Presentor