Yes, Mini-strokes, which are also called as transient ischemic attacks or TIAs, often signal an acute, major stroke. Symptoms are various; they often include vision disturbances or temporary blindness in one eye. A stroke can cause the same symptoms, but they do not disappear as in TIAs.
Optic nerve may swell and inflame because of many different disorders, such as high blood pressure, head injuries, and infections. As a result, vision deteriorates and total blindness may happen.
Yes, it can really happen. but don't be nervous, this usually occurs in the elderly. Because the blood vessels around eyes may be obstructed after stroke, then it leads blindness. This is why your friend said that his grandfather got blindness in one eye from stroke. So everyone should do some exercise to keep health, when we are old that stroke will not find us.
It is true that stroke can cause blindness in one eye. Stroke, also called cerebrovascular accident (CVA), is lack of blood in brain and rapid loss of brain function. It is easy to lead to eye vision problems. Blurred vision, glaucoma, cataracts, even blindness.