A young man with blurring of vision in right eye, followed by left eye after 3 months, showing disc hyperemia, edema, circumpapillary telangiectasia with normal pupillary response with centrocecal scotoma on perimetry, the cause is:
**Core Concept**
Optic disc edema, circumpapillary telangiectasia, and centrocecal scotoma are characteristic features of optic disc drusen, but the given symptoms and findings suggest a more severe condition. The patient's presentation of sequential vision loss in both eyes, disc hyperemia, and edema indicates an inflammatory or neoplastic process affecting the optic nerve.
**Why the Correct Answer is Right**
The patient's symptoms are consistent with optic neuritis, an inflammatory condition of the optic nerve. This can be caused by multiple sclerosis, but in this case, the sequential involvement of both eyes and the presence of circumpapillary telangiectasia suggest a different diagnosis. The patient's presentation is most likely due to a neoplastic process, specifically a glioma or a metastasis to the optic nerve, which is a known complication of systemic cancers, particularly choroidal melanoma.
**Why Each Wrong Option is Incorrect**
**Option A:** Leber's hereditary optic neuropathy (LHON) typically presents with sudden, painless vision loss in young men, but it usually affects both eyes simultaneously and does not cause disc hyperemia or edema.
**Option B:** Optic disc drusen can cause visual field defects, but they do not typically cause sequential vision loss in both eyes or disc hyperemia and edema.
**Option C:** Optic neuritis is the correct answer, but the distractor option is not provided in the question.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with sequential vision loss in both eyes, consider the possibility of a neoplastic process affecting the optic nerve, particularly if there is disc hyperemia or edema.
**Correct Answer:** C. Optic neuritis.