*the 1 in 10,000 number is very high end estimate. From the study:
The estimated rate of Acanthamoeba keratitis is 1 per 250,000 people in the United States, although rates vary among studies: from 1.65-2.01 per million population up to 1 per 10,000 people who wear contact lenses.
The alternative-pop singer Momus contracted that from tapwater in Greece in the 90s, and has worn an eyepatch since.