Every morning I wake up with my left eye irritated and quite dry. Along with this symptom my eyebrow twitches involuntarily and the nostril on the left side is runny. What can cause this? It is very irritating and worrisome for me as my right eye has vision problems due to a childhood injury. I've been told various things by laypersons, including that 'low potassium' can cause involuntary muscle twitches.