How common is keratoconus? More common than you think.

Data from over 4 million patients from a health database in the Netherlands was analyzed to determine the prevalence of keratoconus. Previous studies suggested 1 in 2000 people have keratoconus but this study found the number to be 1 in 375.
These values are 5-fold to 10-fold higher than previously reported values in population studies.