Short acting mydriatic used in fundoscopy is
**Core Concept**
Mydriatics are medications used to dilate the pupils for fundoscopic examination or other medical procedures. Short-acting mydriatics are preferred for fundoscopy as they allow for quick reversal and minimal side effects.
**Why the Correct Answer is Right**
Tropicamide is a short-acting antimuscarinic agent that selectively blocks the muscarinic receptors in the sphincter pupillae, leading to mydriasis. Its rapid onset of action (1-2 minutes) and short duration of action (6-8 hours) make it an ideal choice for fundoscopy. The use of tropicamide allows for quick reversal of mydriasis, enabling the patient to resume normal vision and activities soon after the examination.
**Why Each Wrong Option is Incorrect**
* **Option A:** Cyclopentolate is a medium-acting mydriatic, which is not ideal for fundoscopy as it can cause prolonged mydriasis and cycloplegia.
* **Option B:** Atropine is a long-acting mydriatic, which is not suitable for fundoscopy due to its prolonged effects and potential for systemic side effects.
* **Option D:** Phenylephrine is a selective alpha-1 adrenergic agonist that causes mydriasis by increasing the diameter of the pupil, but it is not commonly used for fundoscopy.
**Clinical Pearl / High-Yield Fact**
When using mydriatics for fundoscopy, it's essential to note that some patients may have pre-existing glaucoma or other ocular conditions that could be exacerbated by mydriasis. Always perform a thorough ocular examination and consider consulting with an ophthalmologist if necessary.
**Correct Answer: C. Tropicamide**