Inherited Retinal Diseases Donate Fundraise Two million people worldwide suffer from Inherited retinal diseases (IRDs), of which Retinitis Pigmentosa is the most common. Collectively, they are the major cause of inherited sight loss, ultimately often leading to total blindness and with profound impacts on patients, their families and society. Difficulties with night vision and peripheral vision are the first things that are noticed. Later, reading vision (detailed vision), colour vision, and central ('straight-ahead') vision are affected. The age at which symptoms start is variable and the rate of deterioration often varies - for example with the different genetic types - but is generally very slow with changes occurring over years rather than months. In approximately half of all cases there are other family members with RP. It affects approximately 1 in 3,000 to 4,000 people. Please help us combat this significant cause of blindness by supporting our appeal into all inherited retinal diseases.