Treatment for blindness represents a major unmet medical need throughout the world, including Europe and the United States. In 2010, there were about 285 million visually impaired people worldwide and around 40 million were totally blind.

The consequences of blindness to sufferers include:

• Deterioration of quality of life;
• Encountering more difficulties in day to day life, with increasing dependency on others;
• A higher risk of depression;
• A two-fold risk of premature death;
• Increased risk of accidents;
• Earlier admission to nursing homes and long-term care facilities.

For society, blindness is a major economic and social issue related to direct healthcare costs and indirect costs (lost productivity, costs of care by non-professionals).

The principal causes of visual impairment :

• Cataract: progressive opacification of the lens of the eye, causing a progressive loss of vision
• Glaucoma: increased intra-ocular pressure damaging the optic nerve
• Diabetic retinopathy: haemorrhage of blood vessels of the retina resulting from damage of
   vessel walls caused by diabetes
• Diseases related to degeneration of photoreceptors: Retinitis Pigmentosa (RP) and AMD
   (Age-related macular degeneration).