Cataracts occur naturally due to the ageing of the eye, and diagnosis in adults over 40 is quite normal. They can also sometimes occur in infants and children as a congenital defect.
Normally, the lens at the front of the eye focuses light onto the retina at the back of the eye, creating a sharp image. When the lens becomes cloudy, the light can’t pass through freely, which is why your vision becomes blurred.
Contrary to popular belief, cataracts are not caused by overuse of the eyes, nor can they be made worse by using the eyes.
Compare the two images below:
As a cataract forms, the lens becomes opaque and light cannot easily be transmitted to the retina.