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Cyclopentolate is a muscarinic antagonist[1]. It is commonly used as an eye drop during pediatric eye examinations to dilate the eye (mydriatic) and prevent the eye from focusing/accommodating (cycloplegic). Cyclopentolate or atropine can also be administered to reverse muscarinic and central nervous system effects of indirect cholinomimetic (anti-AChase) administration.

After instillation of cyclopentolate, pupil dilation (mydriasis) typically lasts up to 24 hours, while paralysis of the ciliary muscle (cycloplegia) typically lasts 6-24 hours[2]. During this time, patients may be more light sensitive than normal and may notice close objects blurred (and possibly distant objects blurred, depending on the patient's visual system). Cyclopentolate is often chosen as a milder, shorter-lasting, cycloplegic alternative to atropine, another cycloplegic agent which lasts much longer. Tropicamide is an even shorter-lasting cycloplegic than cycloplentolate, but is less reliable for finding latent hyperopia. Cyclopentolate drops act rapidly to dilate the pupil.[3] Side effects to cyclopentolate are rare, but can include effects such as disorientation, incoherent speech or visual disturbances during the 24-hour period that the drug has an effect. The side effects are more common in children.

Cycloplegia is necessary in cases of suspected latent hyperopia (or "over-focusing") so that an ophthalmologist or optometrist can accurately measure how much a person has to flex their focusing muscle (accommodation) in order to see in the distance and up-close. Correction of latent hyperopia in children can often prevent, or sometimes correct, unwanted eye turns (strabismus), some forms of refractive amblyopia, and may alleviate eye strain or frontal headaches caused by prolonged near-work. Cycloplegia is also helpful in treating accommodative spasm.

Cyclopentolate was first synthesized in 1952 as a chemical analogue of atropine. It was one of several derivatives of an analogue to tropic acid which were tested for pharmacological action "in a search for new and better antisposmodic agents."[4]

Brand names for cyclopentolate include Cyclogyl, Cylate, Mydrilate, and Pentolair.[5]

Both eyes instilled with cyclopentolate 1%, causing both mydriasis and cycloplegia
Pupil dilation (mydriasis) caused by cyclopentolate 1% instilled into both eyes


  1. ^ "Cyclopentolate". Retrieved June 15, 2012.
  2. ^ Clinical Ocular Pharmacology, 5th edition, Bartlett, 2008. Chapter 9: Cycloplegics. Table 9-1: Mydriatic and Cycloplegic Properties of Anticholinergic Agents. p.127.
  3. ^ "Cyclogyl Eye Drops Medsafe data sheet New Zealand" (PDF). 11 January 2017. Retrieved 3 June 2017.
  4. ^ Treves GR, Testa FC (1952). "Basic Esters and Quaternary Derivatives of β-Hydroxy Acids as Antispasmodics1". Journal of the American Chemical Society. 74 (1): 46–48. doi:10.1021/ja01121a012. ISSN 0002-7863.
  5. ^ "cyclopentolate hydrochloride solution - ophthalmic, Cyclogyl, Cylate, Pentolair". Retrieved June 15, 2012.

Further reading[edit]

John P.Whitcher; Paul Riordan-Eva (2007-10-18). Vaughan & Asbury's general ophthalmology (17th ed.). McGraw-Hill Medical. p. 63. ISBN 978-0071443142. }}