Which eye drop has a red cap and lasts about 4-6 hours?

Which eye drop has a red cap and lasts about 4-6 hours?

• A. Tropicamide
• B. Phenylephrine
• C. Cyclopentolate
• D. Homatropine

Answer: (A)

Short-acting pupil dilation is often linked to a red-cap label. Tropicamide is a fast-acting, short-duration dilating drop that typically lasts about 4–6 hours. It works quickly to widen the pupil but wears off within a few hours, which fits the clue given by the red cap and the 4–6 hour duration. In contrast, cyclopentolate and homatropine produce much longer-lasting dilation (often many hours to days), and phenylephrine is a different type of dilator with a distinct duration profile. So tropicamide best matches both the cap color cue and the 4–6 hour duration.

Short-acting pupil dilation is often linked to a red-cap label. Tropicamide is a fast-acting, short-duration dilating drop that typically lasts about 4–6 hours. It works quickly to widen the pupil but wears off within a few hours, which fits the clue given by the red cap and the 4–6 hour duration. In contrast, cyclopentolate and homatropine produce much longer-lasting dilation (often many hours to days), and phenylephrine is a different type of dilator with a distinct duration profile. So tropicamide best matches both the cap color cue and the 4–6 hour duration.