“At their worst, lash extensions can cause vision loss if corneal scarring occurs from bacterial conjunctivitis or an ulcer,” says Chan. “An ulcer can develop if fibers from lash extensions scratch the corneal surface.” A friend I know, a Certified Lash Technician, no longer does the business of applying lashes. She unfortunately discovered that the products required to use would pull the customers natural lashes out, as well as causing blephitis irritation and potential for liability lawsuits.