Can contact lenses cause blindness?

Not really. Contact lenses are to correct the vision not to blind the person. If contact lens wearer develops a corneal ulcer then it may lead to problems. Corneal ulcer which is an infection could lead to scar, infection inside of the eye ball or corneal melt then it may effect the vision or blindness.
Yes. If you had a complication of contact lens wear such as a severe eye infection, then blindness is a rare possibility. Always follow your eye care provider's contact lens wear recommendations.

Related Questions

Is it possible that contact lenses cause blindness?

Not likely. Contact lenses cannot cause blindness. Uncommonly an infection can be associated with contact lens use, and rarely, this could lead to loss of the eye. This almost never happens. Read more...