the present main causes of blindness in china are senile cataract , primary glaucoma ' trachoma and corneal infections , and 80 % of the blind are over 50 years of age , 75 % become blind before 10 or after 50 years of age , and among 40 % of the blind , the interval between visual loss in both eyes was over 1 year .
C0729777
corneal infections
C0015392
eyes