Low potassium refers to a lower than normal level of potassium in your bloodstream. Potassium is a chemical that is critical to the proper functioning of nerve and muscles cells, particularly heart muscle cells. People who contain low potassium are easy to suffer weakness, tiredness, or cramping in arm or leg muscles, nausea or vomiting, passing large amounts of urine or feeling very thirsty, even fainting. Some abnormal psychological behaviors which are caused by low potassium are depression, psychosis, delirium, confusion, or hallucinations. The individual who is lack of potassium is easy to get body disorders, blurred vision is one of them. Plus, blurry vision can be caused by glaucoma, photophobia and other eye problems. So be careful.