Republican strategist Karl Rove recently implied that Hillary Clinton had brain damage because of her glasses that she wore in 2013 after a fall led to a blood clot. He said “…we need to know what’s up with that”). Well, all I can say is please don’t let Karl Rove guide your understanding of the human brain. Her glasses had something called a Fresnel press-on prism on the left lens. We use them all the time to correct temporary diplopia (double vision). It’s actually a series of small prisms that allow someone who temporarily sees double to see “single” . Once the double vision subsides, this sheet of prisms is simply peeled off of the lens. Blood clots in the brain are notorious for causing double vision by pressing on one of the nerves that controls eye movements. When the clot resolves or is corrected, then the double vision resolves, as well. Temporary double vision is also commonly seen in diabetic patients, kids who are really far-sighted, and older patients. So, the next time someone uses a person’s glasses in a political attack, please ask the attacker to read up on the issue before doing so.