There are two types of Optic Neuritis (ON): Bulbar and Retro-Bulbar. You can see bulbar ON. Retro-Bulbar is within the brain (and that makes for a problem.) Although it is called Retro-bulbar ON, it can effect the Optic Nerve, Optic Chasm, or the Optic Tract. Even with a VEP, you can see the decreased conduction velocity, but can't see the location on the damage. Only about 40% of cased of ON are visible on ophthalmic examination as a "pale edge" to the optic disk.
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To the best of my knowledge, there is no causal relationship between retinal tears or detachments and Optic Neuritis. Flashes, double vision, and blurry vision can happen after ON.
Bob