Cataract is a slowly progressing condition that causes a clouding of the lens of the eyes. It can happen to just one eye or both simultaneously. The most obvious sign of this condition is a blurry vision almost like looking through a dirty window. Other symptoms that you may encounter are double vision not being able to measure the brightness of colours halos around lights difficulty when faced with bright lights and difficulty with night vision. This is a very common problem that crops up usually when you are in your 50s or 60s though it can also happen at