Katarakt, or cataract, is a condition that causes the lens of the eye to become cloudy, leading to blurred vision. It often develops slowly and can affect one or both eyes. Common symptoms include difficulty seeing at night, sensitivity to light, and seeing halos around lights. The primary risk factors for cataracts include aging, prolonged exposure to sunlight, and certain medical conditions like diabetes. Treatment typically involves surgery to remove the cloudy lens and replace it with an artificial one, restoring clear vision for most patients.