All of the following findings are associated with optic neuritis except
**Core Concept**
Optic neuritis is an inflammatory condition affecting the optic nerve, leading to damage of the nerve's myelin sheath. This results in impaired visual function, including decreased vision, color vision defects, and pain on eye movement.
**Why the Correct Answer is Right**
Optic neuritis typically presents with a characteristic clinical picture, including acute onset of pain on eye movement, vision loss, and color vision defects. The pain is often described as aching or burning and is exacerbated by eye movement. The vision loss is usually central and can be accompanied by a relative afferent pupillary defect (RAPD). The condition is often associated with multiple sclerosis, but can also be idiopathic or secondary to other conditions such as infections or autoimmune disorders.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a common finding in optic neuritis. The optic disc is often swollen in optic neuritis due to inflammation and edema of the optic nerve head.
**Option B:** This option is incorrect because it is a characteristic feature of optic neuritis. The pain on eye movement is a hallmark symptom of the condition, often described as aching or burning.
**Option C:** This option is incorrect because it is a common association with optic neuritis. Multiple sclerosis is a common cause of optic neuritis, and the condition often presents as a relapsing-remitting disease.
**Option D:** This option is incorrect because it is not a typical finding in optic neuritis. Optic neuritis does not typically cause a dilated pupil.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of optic neuritis is pain on eye movement, often described as aching or burning. This symptom is highly suggestive of optic neuritis and should prompt further investigation.
**Correct Answer:** D. Optic neuritis is not typically associated with a dilated pupil.