Cyclopentolate

1 medicine

Cyclopentolate is an anticholinergic eye drop that dilates the pupil and freezes focusing for eye exams. In infants and young children it can be absorbed into the body and cause serious anticholinergic side effects.

Cyclogyl

Cyclopentolate

1%

Cyclogyl is a eye care medication containing Cyclopentolate, available as 1% bottles.

from $4.67 / bottle View

Key facts

  • Cyclopentolate is an anticholinergic eye drop used to dilate the pupil and temporarily paralyse the eye's focusing muscle so a doctor can examine the retina and inner eye clearly.
  • One or two drops usually work within 30 to 60 minutes; blurred near vision and light sensitivity can last from several hours up to a day.
  • In infants and young children, especially with stronger drop concentrations, cyclopentolate can be absorbed through the tear duct into the bloodstream and cause serious anticholinergic effects: agitation, disorientation, unsteady movement, or, rarely, seizures.
  • Seek urgent care for sudden severe eye pain, a fast heartbeat, or confusion after the drops are given.

What cyclopentolate treats

Cyclopentolate itself does not treat a disease; it is a diagnostic aid used before eye examinations. It dilates the pupil and stops the eye focusing up close so a clinician can see the retina, optic nerve, and other structures behind the lens, check for conditions such as retinal disease, or look for damage after an eye injury, and get an accurate glasses prescription in children whose eyes over-focus (accommodate) during testing.

How cyclopentolate works

The drops spread across the surface of the eye and block muscarinic receptors on the iris sphincter and ciliary muscle. Blocking these receptors stops the muscles contracting, so the pupil widens (mydriasis) and the lens loses its ability to focus up close (cycloplegia) until the effect wears off.

Before you take it

  • Avoid cyclopentolate if you have untreated narrow-angle glaucoma; widening the pupil can trigger a sudden, sight-threatening rise in eye pressure.
  • Tell the clinician if you or your child has had an unusual reaction to cyclopentolate or similar eye drops before.
  • In babies and young children, the lowest effective strength and dose is used, and gentle pressure over the inner corner of the eye after application reduces how much reaches the bloodstream.
  • Vision stays blurred and light-sensitive for hours afterward; arrange for someone else to drive and bring sunglasses.

Side effects

Common effects are stinging on application, temporary blurred vision, light sensitivity, and a mild headache as the eyes adjust.

Stop and seek urgent medical care for:

  • Sudden, severe eye pain or a rapid rise in redness.
  • A fast or irregular heartbeat, flushed dry skin, or confusion, which can signal a systemic anticholinergic reaction.
  • In infants: unusual drowsiness, feeding difficulty, or abdominal distension.

Safety essentials

  • Cyclopentolate can cause systemic anticholinergic toxicity in infants and young children: confusion, a racing heart, or rarely seizures, so the lowest effective concentration is used and children are watched after dosing.
  • Untreated narrow-angle glaucoma is a hard contraindication; pupil dilation can precipitate an acute attack.
  • Vision will not return to normal for several hours; avoid driving, reading fine print, or working with machinery until it does.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.