About 2 million people are now blind due to trachoma, which infects about 80 million people. Twenty years ago, it infected 4-5 times as many people, and perhaps blinded the same proportion as now, which would have been 8-10 million people. If the decrease in trachoma since then has been linear, then the last ten years have seen a decrease in trachoma blindness of 3-4 million people and a decrease in trachoma infections of about 140 million people. At an average number of life-years lost due to blindness of 10 years, that would be about 35 million life-years. Infection may affect patients to an extent of 1 life-year, or 140 million life-years. The total number of life-years saved due to trachoma controls in the past ten years has thus been 175 million life-years.
Human News aims to devote 1 character to each 40,000 life-years, or 1000 average lives. Thus, the number of characters could be 175 million life-years / 40,000 life-years/character = 4400 characters.