Chlamydia trachomatis is a bacterium that causes a disease called trachoma. If left untreated, this disease can cause the eyelashes to grow inward, scratching the eye, and eventually leading to irreversible blindness. This blinding trachoma occurs mostly in under-developed countries where hygiene and sanitary conditions are poor. It is the world's leading cause of preventable blindness. The bacterium is spread by direct contact with eye, nose, and throat secretions from infected individuals. It is frequently passed from child to child and from child to mother.
As far as the name of the charity goes, I'm not sure as to which one you are directly referring to, but one charity that works to prevent this disease is the International Trachoma Initiative (www.trachoma.org). They currently help implement the "SAFE" strategy in 15 countries around the world. The SAFE strategy was developed by the World Health Organization; it stands for Surgery, Antibiotics, Facial cleanliness, and Environmental improvement. This strategy has been proven to effectively eliminate blinding trachoma.
References:
http://www.trachoma.org/
http://www.who.int/topics/trachoma/en/
http://www.nlm.nih.gov/medlineplus/ency/article/001486.htm