A sudden sensitivity to light. If your eyes have suddenly become extremely sensitive to light, this could be a sign of a brain aneurysm. Be cautious in self-diagnosing, though, as other factors can cause this symptom as well. Among these other medical conditions are migraines, or even old age. A sudden light-sensitivity must be taken especially seriously if it is accompanied by a sudden and extremely intense headache. All these symptoms are caused by pressure exerted by an aneurysm on various nerves that lead from the brain.