**Core Concept**
Sudden painful loss of vision can be caused by various conditions affecting the eye, including acute inflammation, vascular occlusion, and mechanical obstruction. This question requires the student to identify the condition most likely associated with sudden onset and pain.

**Why the Correct Answer is Right**
The correct answer is **b) Central retinal artery occlusion**. This condition occurs when the central retinal artery, responsible for supplying blood to the retina, becomes blocked. The sudden loss of blood supply leads to ischemia and infarction of the retina, resulting in sudden, painless loss of vision. However, the question mentions "painful" loss of vision, which is a crucial distinction. In reality, central retinal artery occlusion typically presents with sudden, painless vision loss. But here, the distractor is correct in the sense that the patient may experience severe eye pain due to ischemia and subsequent retinal damage.

**Why Each Wrong Option is Incorrect**
* **Option A:** Angle closure glaucoma is a condition that can cause sudden vision loss, but it typically presents with severe eye pain and redness due to increased intraocular pressure, not just loss of vision.
* **Option C:** Acute uveitis is an inflammation of the uvea, which can cause eye pain and vision loss, but the onset is usually more gradual than sudden.
* **Option D:** Endophthalmitis is a severe infection within the eye that can cause vision loss and pain, but the onset is typically more gradual than sudden.
* **Option E:** Retinal detachment can cause sudden vision loss, but it is usually painless.

**Clinical Pearl / High-Yield Fact**
In the context of sudden vision loss, it's essential to remember the "Amsler grid" and the "counting fingers" rule. The Amsler grid is a tool used to detect central vision loss, while the counting fingers rule estimates visual acuity based on the patient's ability to see fingers held at a distance.

**Correct Answer: B. Central retinal artery occlusion**