Cyclopentolate Hydrochloride (HCl)

• Type: Mydriatic and cycloplegic agent (anticholinergic)

• Main Use: Temporarily dilates the pupil and paralyzes the eye’s focusing muscle (ciliary muscle).

How It Works

• Cyclopentolate blocks acetylcholine receptors in the eye’s muscles.

• This causes:

  • Mydriasis – pupil dilation (for examination or treatment)

  • Cycloplegia – relaxation of the ciliary muscle, preventing the eye from focusing (important for measuring refractive error in children).

Forms Available

• Usually in eye drop form (commonly 0.5%, 1%, or 2% solutions).

Common Uses

• Diagnostic purposes:

  • Eye examinations (fundus exams)

  • Refraction tests in children (to accurately measure vision prescription without interference from eye focusing)

• Therapeutic purposes:

  • Treatment of iritis or uveitis (eye inflammation) to reduce pain and prevent adhesions

  • Pre- and post-surgical use to keep the pupil dilated when needed

Advantages

• Shorter duration of action compared to some other mydriatics (like atropine), so recovery of normal vision is faster.

• Effective for both pupil dilation and pain relief in inflammatory eye conditions.

Possible Side Effects

• Eye-related:

  • Temporary blurred vision

  • Light sensitivity (photophobia)

  • Mild stinging on instillation

• Systemic (rare):

  • Dry mouth, flushing, rapid heartbeat

  • Confusion or restlessness (more likely in children if absorbed too much)

Precautions

• Wear sunglasses outdoors until the effect wears off (to protect from bright light).

• Use with caution in infants, children, and elderly (risk of systemic side effects).

• Avoid touching dropper tip to eye or skin to prevent contamination.

• Effects usually wear off in 6–24 hours, but can last longer in some people.