How long does it typically take to see ocular dilation after topical atropine sulfate administration?

How long does it typically take to see ocular dilation after topical atropine sulfate administration?

• A. 5-10 minutes
• B. 20-30 minutes
• C. 60-90 minutes
• D. 2-4 hours

Answer: (B)

Onset of mydriasis after topical atropine depends on how quickly the drug diffuses through the cornea to block muscarinic receptors in the iris sphincter. Because this diffusion and receptor blockade take time, dilation is typically first noticeable around twenty to thirty minutes after instillation, with the full effect continuing to develop over the next hour. This slower onset reflects atropine’s long-acting, indirect mechanism compared with shorter-acting mydriatics. In practice, dilation would not be expected at five to ten minutes, and waiting until sixty to ninety minutes covers the later phase rather than the initial onset. A two- to four-hour window would miss the earliest observable effect and isn’t the typical time to first notice dilation.

Onset of mydriasis after topical atropine depends on how quickly the drug diffuses through the cornea to block muscarinic receptors in the iris sphincter. Because this diffusion and receptor blockade take time, dilation is typically first noticeable around twenty to thirty minutes after instillation, with the full effect continuing to develop over the next hour. This slower onset reflects atropine’s long-acting, indirect mechanism compared with shorter-acting mydriatics. In practice, dilation would not be expected at five to ten minutes, and waiting until sixty to ninety minutes covers the later phase rather than the initial onset. A two- to four-hour window would miss the earliest observable effect and isn’t the typical time to first notice dilation.