Rod-cone dystrophy is the most common kind of retinitis pigmentosa (RP) and the one that is often referred to as RP.
In this condition the rods are initially more affected than the cones giving problems with night blindness (nyctalopia). Later there are problems with the peripheral visual field, central vision and colour vision.
Patients generally present in childhood or teenage years with symptoms of night blindness, and on examination of the retina, dark pigment changes may be seen, often described as bone spicules. Age of onset and visual prognosis are very variable.
The condition can be inherited in different ways, recessive being most common.