Cataract is a common eye condition characterized by the clouding of the eye's natural lens, which lies behind the iris and pupil. This clouding obstructs light from reaching the retina, leading to blurred vision, difficulty seeing at night, and sensitivity to light.
Option A: Eye is correct because cataracts exclusively affect the lens of the human eye. This condition is a leading cause of blindness worldwide, but it is treatable with surgery to replace the cloudy lens with an artificial one. Option B, Trachoma, is incorrect because it is a bacterial infection of the eye, not an organ itself. Options C and D, Lungs and Throat, are incorrect as they are parts of the respiratory and digestive systems, respectively, and are not affected by cataracts.