How can corneal abrasions lead to blindness?

Scarring. Corneal abrasions, if severe or untreated can lead to corneal infections and scarring which can cause vision loss.
Scars and infection. Corneal abrasions are scratches on the eye's surface. Repeated abrasions in the same area create opaque scars. Additionally, corneal abrasions can lead to infections, which can cause permanent vision loss in the form of scars or damage to the retina (film layer) and optic nerve ("video cable") of the eye.

Related Questions

How can corneal abrasions lead to eventual blindness?

Infection/perf. One possibility is that the abrasion leads to an infection that then causes permanent damage to the eye. Another possibility is that the abrasion penetrated into the cornea and caused internal damage that could lead to vision loss. Read more...