Cataracts are when the lens in the eyes become cloudy, either completely or partially. Often cataracts appear with older age. When the lens becomes clouded, vision can weaken and be blurred. Treatment for cataracts is usually a simple cataract surgery, which is often does as a day case procedure with a local anaesthetic. During cataract surgery, the cloudy lens is replaced with a clear plastic one. Depending on whether you have cataract surgery privately or not, the replacement lenses inserted may be multifocal or monofocal.