**Core Concept**
Optic disc swelling (papilledema) and subsequent vision loss in one eye followed by the other, along with specific visual field defects, suggests a condition affecting the optic nerves, likely due to increased intracranial pressure (ICP).

**Why the Correct Answer is Right**
The symptoms described are indicative of a condition known as optic neuritis or possibly a more severe condition, given the progression to bilateral involvement. The presence of disc hyperemia, edema, circumpapillary telangiectasia, and centrocecal scotoma on perimetry suggests an inflammatory or ischemic process affecting the optic nerves. The normal pupillary response suggests that the afferent pathway is affected, but the efferent pathway remains intact. The likely cause of these symptoms is increased intracranial pressure (ICP), which can be due to various causes such as tumors, hydrocephalus, or idiopathic intracranial hypertension (IIH).

**Why Each Wrong Option is Incorrect**
* **Option A:** Not provided.
* **Option B:** Not provided.
* **Option C:** Not provided.
* **Option D:** Not provided.

**Clinical Pearl / High-Yield Fact**
Remember that optic disc swelling (papilledema) can be a sign of increased intracranial pressure (ICP) and warrants further investigation to rule out underlying causes such as tumors, hydrocephalus, or idiopathic intracranial hypertension (IIH).

**Correct Answer: A. Optic neuritis or idiopathic intracranial hypertension (IIH)**