Optic nerve hypoplasia
Macular disease
Noonan syndrome
Head trauma, tympanic membrane rupture
Brain tumor
Stroke
Chiari malformation
Meniere's disease, BPPV, labyrinthitis, Vestibular Neuritis
Multiple sclerosis
Wernicke-Korsakoff syndrome, thiamine deficiency
Tox causes:
Alcohol intoxication, benzodiazepines, barbiturates, GHB
Ketamine, Phencyclidine
Amphetamines, MDMA
Marijuana
Lithium
Phenytoin, fosphenytoin, carbamazepine, oxcarbazepine, lacosamide, gabapentin
Salicylates, NSAID toxicity
Alcohol intoxication, benzodiazepines, barbiturates, GHB
Ketamine, Phencyclidine
Amphetamines, MDMA
Marijuana
Lithium
Phenytoin, fosphenytoin, carbamazepine, oxcarbazepine, lacosamide, gabapentin
Salicylates, NSAID toxicity
Nystagmus
Optic nerve hypoplasia
Internuclear ophthalmoplegia
Macular disease
Ataxia
Noonan syndrome
Ataxia 
Head trauma, tympanic membrane rupture