11.5 Mydriatics and cycloplegics

Caution: Darkly pigmented iris is more resistant to pupillary dilatation and caution should be exercised to avoid over dosage.


Antimuscarinics dilate the pupil and relax the ciliary muscle resulting in mydriasis and cycloplegia. They can raise Intra Ocular Pressure (IOP) and should be used with caution in those patients susceptible to angle closure.

Atropine sulphate
  • Eye drops 1% (£233.80 = 10ml)
  • Single use eye drops 1% (£16.31 = 20 x 0.5ml)
  • Eye ointment 1% (available from Martindale)


  1. Atropine has the longest activity, sometimes up to a week. Atropine has a tendency to cause hypersensitivity.
  2. Atropine ointment 1% is sometimes preferred for children aged under 5 years to produce cycloplegia prior to refraction, because the ointment formulation reduces systemic absorption.
Cyclopentolate hydrochloride
  • Eye drops 1% (£8.08 = 5ml)
  • Single use eye drops 1% (£12.26 = 20 x 0.5ml)


  1. Cyclopentolate activity lasts for up to 24 hours. It is included for corneal injuries, along with homatropine 2%, in order to reduce ciliary spasm and pain.
  • Eye drops 1% (unlicensed)
  • Single use eye drops 0.5%, 1%


Phenylephrine hydrochloride
  • Single use eye drops 2.5%, 10% (£12.46 = 2.5% x 20 (0.5ml), £12.82 = 10% x 20 (0.5ml))


  1. Phenylephrine hydrochloride is used for mydriasis in diagnostic procedures and pre-operative use.
  2. Phenylephrine 10% is more likely to cause cardiovascular side-effects and therefore it should not be used routinely.

Combination products


(Tropicamide with phenylephrine and lidocaine)

  • Solution for injection 0.2mg/ml + 3.1mg/ml + 10mg/ml ampoules 0.6ml


  1. Prescribe by brand (to aid identification where products contain multiple ingredients, or to prevent confusion where multiple brands contain similar ingredients)


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