Hello and welcome to HCM! I read carefully your description of signs and symptoms! It sounded really familiar since almost all of us have gone through such an episode in our lives. The most common cause that produces what you described is orthostatic hypotension (or low blood pressure due to the position of the body): when you remain sitted for long periods of time the blood tends to be concentrated to lower extremities because of gravity and because you are not active. When you suddenly stand up, it takes some seconds for the body to re-distribute the necessary amount if blood to the brain and this causes a short period of stars in the eyes, dizziness, blurred vision, etc. In the absence of other information from you (such as age, previous or current health conditions, etc.) and if this situation happens quite seldom, then you do not need to worry. But, if it happens frequently then it could indicate heart or coronary heart problems. In this case you definitely need to consult your physician. An eye examination could be helpful as well in order to exclude or confirm high blood pressure. Hope I anwered your question! Best!