Okay, let me try to work through this. The question is about the oculocardiac reflex and asks which statement is not true. First, I need to recall what the oculocardiac reflex is. From what I remember, it's a reflex that causes a decrease in heart rate in response to stimulation of the eye structures. It's mediated by the vagus nerve, right? So when there's pressure on the eye, like during an eye exam or surgery, the afferent pathway is via the ophthalmic division of the trigeminal nerve. Then, the efferent pathway is through the vagus nerve, leading to bradycardia.

The question is an "except" question, so one of the options will be false. Let's think about the typical features. The reflex is a vagally mediated response. It's commonly seen during ophthalmic procedures, especially in children. So if an option says it's mediated by the sympathetic nervous system, that would be incorrect. Also, the reflex causes bradycardia, not tachycardia. So if any option mentions tachycardia, that's a wrong one. Another point is that the reflex is more prominent in children, so if an option states it's more common in adults, that's false.

Now, considering the possible distractors. Let's say the options are like:

A. Mediated by vagus nerve
B. Causes bradycardia
C. Triggered by ocular manipulation
D. More common in adults

In this case, D would be the incorrect statement because the reflex is more common in children. So the correct answer is D. The key here is knowing that the oculocardiac reflex is vagally mediated and that it's a concern in pediatric ophthalmic procedures. The clinical pearl is to be aware of this during eye exams, especially in kids, to prevent complications from bradycardia.

**Core Concept**
The oculocardiac reflex is a **vagally mediated** response triggered by stimulation of the **trigeminal nerve (ophthalmic division)**, leading to **bradycardia** or **asystole**. It is classically elicited during **ocular manipulation** (e.g., eye pressure, surgery) and is more pronounced in **children** due to heightened vagal tone.

**Why the Correct Answer is Right**
The reflex occurs when ocular pressure activates **trigeminal afferents**, which synapse in the **nucleus tractus solitarius**. This triggers **vagal efferents** (via the **vagus nerve**) to the heart, causing **bradycardia** or **asystole**. It is a protective mechanism but can be dangerous during procedures like **cataract surgery** or **lumbar puncture** in pediatric patients. The **absence of sympathetic activation** distinguishes it from other reflexes.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect if it claims the reflex is mediated by the **sympathetic nervous system**—it is purely **parasympathetic/vagal**.
**Option B:** Incorrect if it states the reflex causes **tachycardia**—it induces **bradycardia** via vagal stimulation.
**Option C

✓ Correct Answer: B. It is mediated by occulomotor and vagus nerve