RP is retinitis pigmentosa, a group of genetic conditions which result in sight loss. Typically vision deteriorates in a narrowing field, but this varies greatly and more is explained about this on the next two pages. There are many terms used to describe particular types of RP, which are also described in this section.
The level of visual impairment varies because there are dozens of different gene faults that can cause RP, and even people in the same family affected by the same gene can experience differing rates and patterns of sight loss.
At present RP is not curable, though research is well advanced and the outlook is increasingly optimistic that a treatment will be made available.
You can learn a lot more about the condition itself and about research progress at the separate RP Fighting Blindness website.