A cataract is a clouding of lens in the eye that affects vision. Most cataracts are related to aging. Patients will find cloudy or blurry vision, prescription changes frequently which gradually results in poor vision or even blindness. Symptoms like double or multiple images and insufficient colour contrast may also happen. Other types of cataract may cause by injury or complication of other diseases. The symptoms of early cataract may be improved with new eyeglasses. A cataract needs to be removed only when vision loss interferes with everyday activities. Optometrists are the key person to monitor your cataract condition and advise the appropriate time for surgery.