What is retinal pigmentation and is it serious?

Inherited eye diseas: Retinitis pigmentosa (rp) is a group of similar-appearing eye diseases that are hereditary in nature and can lead to blindness. There is no known effective treatment at this time. Rp often causes night blindness and reduction of peripheral vision. More advanced disease causes loss of central vision. The genetic defect in some autosomal dominant forms of rp is known.