Drop that is used for cycloplegic refractions?

• A. Cyclopentolate or Cyclogyl
• B. Tropicamide
• C. Phenylephrine
• D. Atropine

Answer: (A)

Blocking accommodation is essential for an accurate refraction, so a cycloplegic drop is used. Cyclopentolate provides reliable cycloplegia with a practical duration for routine refractions, especially in children. It works by inhibiting muscarinic receptors in the ciliary muscle, causing paralysis of accommodation and mild pupil dilation. Onset is about 30–60 minutes, and the effect lasts roughly 24 hours, making it ideal for a single visit refraction. Tropicamide dilates the pupil but gives only minimal cycloplegia, so it’s not as reliable for precise measurements. Phenylephrine is only a mydriatic and does not affect accommodation. Atropine causes very long-lasting cycloplegia with significant systemic risk, so it’s not used routinely for refractions.