Input (grade 8): Chlamydia conjunctivitis or trachoma was once the most important cause of blindness worldwide, but its role diminished from 15% of blindness cases by trachoma in 1995 to 3.6% in 2002.
Output (grade 7): Chlamydia conjunctivitis or trachoma is a common cause of blindness worldwide. The World Health Organization estimates that it accounted for 15% of blindness cases in 1995, but only 3.6% in 2002.