A resident needs mydriasis alone for a quick fundus examination in an outpatient clinic and wants the pupil to return to normal the same evening. Which mydriatic best fits this requirement?
- A Atropine
- B Tropicamide ✓
- C Homatropine
- D Phenylephrine
Correct answer: B. Tropicamide
Explanation
Tropicamide is the shortest acting antimuscarinic mydriatic, producing dilation for about 6 hours with minimal cycloplegia, ideal for fundoscopy. Atropine causes mydriasis lasting 7 to 10 days and homatropine 2 to 3 days, both far too prolonged. Phenylephrine produces mydriasis without cycloplegia but acts through alpha-1 receptors and lasts about 12 hours; more importantly, the classic single-best answer for the shortest acting mydriatic used before fundus examination is tropicamide.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.