About eye diseases Understanding Cataracts Cataracts occur when changes in the lens of the eye cause it to become less transparent. resulting in cloudy or misty vision. Cataracts usually develop due to age, although this is not always the case. Cataracts are the leading cause of blindness globally. The good news is that they are entirely treatable with around 350,000 cataract operations performed by the NHS every year. More research is needed to find non-surgical treatments for cataracts. You can help to find new treatments and end sight loss forever. Please make a gift today. Donate now Causes of cataracts Cataracts most often start to develop in a person's lens as they get older. The changes to the lens stop light from reaching the back of the eye. The lens is a crystalline structure that sits just behind the pupil - the black circle in the centre of the eye through which light enters. The light is focused by the cornea and the lens on the retina, a layer of light-sensitive cells at the back of the eye, which creates an electrical interpretation of the image which is transmitted to the brain, enabling us to see. Diagnosis of cataracts A regular eye test can detect cataracts, your optician will measure how well you see at various distances. The usual symptoms are blurred or misty vision, lights appearing very bright or glaring, difficulty seeing in low light and colours appearing faded. Over time, cataracts become worse and start to affect vision. Eventually, surgery is needed to remove and replace the affected lens. Treatment of cataracts Currently the only treatment for cataracts is surgery to remove the cataract. This restores vision by allowing light reaching the back of the eye again. The operation is generally very safe and takes little more than 15 minutes to complete. More research is needed to find non-surgical treatments for cataracts. You can help to find new treatments and end sight loss forever. Please make a gift today. Donate now For full medical information about cataracts, please visit the NHS website.