Congenital stationary night blindness (CSNB) is a group of non-progressive retinal disorders characterized by an abnormal dark-adaptation curve, poor visual acuity, nystagmus, myopia (ranging from low to high), strabismus, and fundus abnormalities.  There are two forms of CSNB, complete (CSNB1) and incomplete (CSNB2), according to the degree of rod function, measured by dark adaptometry or electroretinogram (ERG).  The b-wave responses in patients with CSNB1C are severely deficient, but the a-waves are normal.

CSNB can be inherited as X linked recessive, autosomal recessive, or autosomal dominant patterns. CSNB1C is inherited as an autosomal recessive trait and caused by mutations in the TRPM1 gene.