X-linked congenital stationary night blindness (XLCSNB) is a disorder of the retina. People with this condition typically experience night blindness and other vision problems, including loss of sharpness (reduced visual acuity), severe nearsightedness (myopia), nystagmus, and strabismus. Color vision is typically not affected. There are two major types of XLCSNB: the complete form and the incomplete form. Both types have very similar signs and symptoms. However, everyone with the complete form has night blindness, while not all people with the incomplete form have night blindness. The types are distinguished by their genetic cause.