Usher syndrome is a hereditary disease that affects two sensory organs, the eye and the ear. It is always accompanied by a hearing disorder in the inner ear and a retinal disease that sets in later. The name of the retinal disease is "Retinopathia Pigmentosa" (old name: "Retinitis Pigmentosa") and is abbreviated as "RP". The retinal disease has the effect that the photoreceptors (= visual cells) in the eye slowly and steadily die off. The photoreceptors are those rods and cones (also called photoreceptors) that are necessary for seeing light - dark, black - white and colour.

Typical symptoms of retinopathy pigmentosa are initially night blindness, sensitivity to changes in light and a slow onset of visual field loss. It is important to note that the course of the disease is very gradual and is therefore not noticed by the affected person at first.