Congenital stationary night blindness

Congenital stationary night blindness, or CSNB, is a rare retinal disorder that does not progress over time. People with it often have difficulty adapting to low light because transmission from the photoreceptors is impaired, and they may also have reduced visual acuity, myopia, nystagmus, fundus abnormalities and strabismus. It has two forms: the complete form, type 1, in which downstream bipolar cells cannot detect signals from photoreceptors and which can involve genes such as NYX, and the incomplete form, type 2, in which the photoreceptors themselves transmit poorly, mainly through mutations in CACNA1F. It can be inherited in an X-linked, autosomal dominant or autosomal recessive pattern depending on the gene involved, and similar conditions occur in horses and dogs.