Intermittent blurriness could be caused by dryness, if the front surface of your eye (the cornea) momentarily dries out. When you blink a few times it re-lubricates and you can
see better. Usually pain with dry eyes is on the surface of the eye, not deep inside or the temple, however. To guess at a cause one would have to know how old you are, under what circumstances it occurs - when you are driving your car with the air-conditioning on, when you are at home with the heat on, etc - and whether it's associated with using your eyes, for example when you are reading for an extended period, when you move your eyes or blink,etc. Not knowing any of this, I would suggest you to avoid having either cold or heat blowing at your face, use a humidifier at home, keep track of and write down the circumstances and timing of the occurrences and report that to your eye doctor and in the meantime use artificial tears and consider taking a capsule of omega-3 fatty acids (fish oil), which may help alleviate dryness.