Contributor: Gordon K. Klintworth
Night blindness (nyctalopia) is a symptom of many chorioretinal degenerations that affect the rods. The most common disorder of this type is retinitis pigmentosa. Night blindness is also a manifestation of  Vitamin A deficiency. In addition it is a feature of the various types of congenital stationary night blindness [night blindness - congenital stationary] and Oguchi disease. The term congenital stationary night blindness includes a heterogenous group of inherited disorders with congenital or early onset night blindness and a lack of progressive retinal degeneration. Several types of congenital stationary night blindness are recognized based on the mode of inheritance and measurements of retinal function.