In a healthy eye, the iris (the colored part of the eye) regulates the amount of light that enters the eye through the pupil. The light passes through the lens, where it is focused onto the retina at the back of the eye. Signals are then sent from the retina to the brain via the optic nerve, where they are translated into the images you see.
A cataract is a clouding of the normally clear lens in your eye. Though painless, cataracts can blur your vision by restricting the amount of light that enters your eye. In addition to hazy or cloudy vision, indications of cataracts include unusual glare, poor night vision, and a change in how your eyes perceive colors. An eye with a cataract functions normally except that the lens has grown cloudy. Light enters the eye as usual, but the clouded lens disperses the light, causing the retina to have difficulty transmitting a clear image. Because the light that the retina receives is patchy, the retina’s transmissions to the brain are also affected, resulting in hazy, blurred vision.
Most people’s lenses will naturally become slightly cloudy as they age, and because cataracts tend to develop slowly, surgery may not be immediately necessary. It is when your ability to read, drive, or carry out other normal activities is hindered, that cataract surgery will likely be the best possible solution.