Welcome to question of the Day #19

Welcome to question of the Day #19

What are the disadvantages of cycloplegic refraction?

I will focus on the use of cyclopentolate 1% as in my experience this is the most frequently used drug prior to cycloplegic refraction.

In general, the disadvantages of cycloplegic refraction are:

Distress to the patient on instillation of drops as they sting.

Subsequent breakdown in child–practitioner relationship when the child returns for refraction about 30 minutes after instillation. This can make retinoscopy difficult for the practitioner.

Photophobia caused by dilated pupils

Decreased ability in close-work tasks because of the cycloplegia.

Difficulty in assessing axes in the presence of aberrations resulting from a large pupil diameter. The best guideline for retinoscopy is to neutralise the central 4mm of the pupil, ignoring the periphery. Also, a retinoscope light of low to medium intensity helps to reduce any aberrations.

A risk of ocular side effects and adversereactions which take the form of irritation, lacrimation, conjunctival hyperaemia, allergic blepharoconjunctivitis and elevated intraocular pressure. These are rare.

A risk of systemic side effects and adverse reactions which take the form of drowsiness, ataxia (lack of voluntary coordination of muscle movements causing gait abnormality, speech changes, and abnormalities in eye movements), disorientation, restlessness and visual hallucinations. These are very rare.

I have undertaken around 2000 cycloplegic refractions on children using cyclopentolate 1% and have never seen raised intraocular pressure. The only systemic reaction I have seen is restlessness, in around 5%.