Refraction cycloplegic

Manifest Refraction. Topically applied cycloplegics may affect the manifest (subjective) refractive error. When indicated, cycloplegic refraction may be performed after the initial manifest refraction or as the initial refractive procedure in children (see Chapter 21). 

Cyclopentolate Overdosage for cycloplegic refraction Hallucinatory behavior... 

Because of its prolonged mydriatic and cycloplegic effect and relatively weak cycloplegic action, particularly in darkly pigmented irides, homatropine is not a drug of choice for fundus examination or cycloplegic refraction. Homatropine is primarily used in the treatment of anterior uveitis, in which its effects are similar to those of atropine. 

In low dosages scopolamine can produce effects on the CNS, presmnably due to its ability to penetrate the blood-brain barrier. Drowsiness and confusion are frequently reported. Patients also tend to exhibit a higher incidence of idiosyncratic reactions to scopolamine than to other anticholinergic agents, and, hence, it is not the drug of first choice for cycloplegic refraction or treatment of anterior uveal inflammations. Its use is reserved primarily fiar patients who exhibit sensitivity to atropine. 

Cycloplegic refraction is also indicated for patients with active accommodative systems whose best corrected visual acuity in each eye is less than 20/20 and for whom there is no apparent reason for the decreased vision. It allows the clinician to determine whether uncorrected refractive error is responsible for the reduced acuity. This data may be particularly helpful in young patients with uncorrected antimetropia, latent hyperopia, or hyperopic anisometropia. 

Finally, patients whose visual signs or symptoms do not correlate with the nature and degree of their manifest refraction may benefit from cycloplegic evaluation. A cycloplegic refraction aids in the differential diagnosis by helping to ensure that the patient s problem is not refractive in natiU e.The clinician can then concentrate on other aspects of the visual system. Box 21-1 summarizes the indications for cycloplegic reflaction. 

The most widely accepted cycloplegic refraction regimen includes instillation of one drop of topical anesthetic followed by one drop of 1% cyclopentolate and one drop of either 2.5% phenylephrine or 1% tropicamide to facilitate dilation. After waiting 5 minutes, instillation of one... 

After retinoscopy, subjective refraction may be attempted, although practitioners often cannot perform this procedure on young patients because of their lack of maturity and cooperation. The practitioner should note that spherical aberration can cause errors in the subjective cycloplegic refraction just as it does in retinoscopy. 

In summary, cycloplegic refraction is a valuable and perhaps underused refractive procedure that the chni-cian should consider when applicable. In contemporary... 

Hofmeister EM, Kaupp SE, SchaUhorn SC. Comparison of tropicamide and cyclopentolate for cycloplegic refractions in myopic adult refractive surgery patients. J Cataract Refract Surg 2005 31 694-700. 

Kawamoto K, Hayasaka S. Cycloplegic refractions in Japanese children a comparison of atropine and cyclopentolate. Ophthalmologica 1997 211 57-60. 

RosenbaumAL, Bateman JB, Bremer DL, et al. Cycloplegic refraction in esotropic children. Cyclopentolate versus atropine. Ophthalmology 1981 88 1031-1034. 

Tropicamide, an anticholinergic agent causing mydriasis and cycloplegia, is used for cycloplegic refractions and fundus examinations. 

Mirshahi A, Kohnen T. Acute psychotic reaction caused by topical cyclopentolate use for cycloplegic refraction before refractive surgery case report and review of the literature. J Cataract Refract Surg 2003 29(5) 1026-30. 

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