<unk>  is a group of medical disorders defined by visual impairment due to<unk>  nerve damage secondary to a<unk>  substance and/or<unk>  deficiency.  The causes of these disorders are various, but they are linked by shared signs and symptoms, which this article will describe.  In several of these disorders, both<unk>  and<unk>  factors play a role, acting synergistically.
Toxic and Nutritional Optic Neuropathy
Endogenous endophthalmitis
Subacute myelo-optic neuropathy
Oculocerebrorenal syndrome
Bacterial endophthalmitis
Cerebral vasculitis
Post-operative endophthalmitis
Post-traumatic endophthalmitis