Early symptoms of cataract are common: 1, vision loss, which is the most obvious and important symptom of cataract, especially in bright light pupil constriction, the light into the eye is reduced, this time the vision is not as good as in low light.2, contrast sensitivity decreased.3, refractive changes, can produce nuclear myopia, can make the original old eyesight reduced.4, monocular diplopia or polyphthalmos.5, glare, due to crystalline clouding, make the light into the eye scattered caused.6, color vision changes, the patient’s color sensitivity to light decreased.6, color perception changes, the patient’s color sensitivity to light decreased. Clouding, so that the light entering the eye caused by scattering. 6, changes in color vision, the patient’s sensitivity to the color of light.