3-methylglutaconic aciduria type III (MGA III) is an organic aciduria characterised by the association of optic atrophy and choreoathetosis with 3-methylglutaconic aciduria.

Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery.