How likely is it that someone will get retinitis pigmentosa?

Inherited Disease: Retinitis pigmentosa is an inherited form of retinal disease that may decrease vision or even complete blindness (unusual). There are dozens of syndromes (diseases without obvious cause) that have characteristic eye findings of rp. Usually there is loss of visual field and difficulty with going from light/dark. Central vision loss is associated, complete blindness rare.

Uncommon unless....: Rp is a genetic disease. You are not likely to get it unless you inherited the defective genes from one or both parents. If you have other siblings with rp, then you may be at risk. If this is the case, then you should get get examined by the same specialist.