Blindness

The group of conditions known as retinitis pigmentosa or RP is the most common cause of inherited blindness. Initially the rods in the retina begin to die and the cones at the center of the retina, known as the macula, will also be lost.

The first symptom of this progressive disease is loss of night vision. Peripheral daylight vision gradually deteriorates resulting in tunnel vision and total blindness may be the final result. The progression of this disease is unstoppable and by aged 40, the victims are usually totally blind. RP is caused by a mutation in one or more genes and occurs in one in 80 individuals. The disease only appears when 2 carriers of this mutated gene have a child. The hope for treatment lies in 3 areas. The first lies in delaying the rate of cell death by use of drugs. The second is use of gene therapy in which defective genes are replaced by those that function normally and the third is use of cell transplantation. Research is in progress to replace degenerated rods and cones with fully functioning receptor cells.