Painless loss of vision is seen in all, EXCEPT:
**Core Concept**
Painless loss of vision can be due to various causes, including non-arteritic anterior ischemic optic neuropathy (NAION), optic neuritis, or compressive lesions affecting the optic nerve. These conditions often result from damage to the optic nerve or retina, leading to vision loss without associated pain.
**Why the Correct Answer is Right**
Painless loss of vision is a characteristic feature of NAION, which occurs due to ischemia of the optic nerve head, often in the context of systemic vascular disease. The exact mechanism is not fully understood, but it is thought to involve a combination of factors, including vascular insufficiency, increased intracranial pressure, and optic disc swelling.
**Why Each Wrong Option is Incorrect**
**Option A:** Not available.
**Option B:** Optic neuritis, a demyelinating condition affecting the optic nerve, often presents with pain on eye movement. This is a key distinguishing feature from painless loss of vision.
**Option C:** Compressive lesions, such as those caused by pituitary tumors or meningiomas, can also cause painless loss of vision. This occurs due to mechanical compression of the optic nerve or chiasm.
**Option D:** Not available.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that painless loss of vision is a red flag symptom, particularly in older adults, and requires prompt evaluation to rule out underlying conditions such as NAION or compressive lesions.
**Correct Answer: B. Optic neuritis often presents with pain on eye movement.**