Well, most people have no any reactions when smoke weed. But a little part of human beings are not suitable to smoke. It is true that some people may be allergic to marijuana, then dry throat, dry eyes, nose problems and itchy eyes go together. The most important factor is that marijuana dries out all your mucous membranes and the smoke constantly irritate your eyes. If you just feel itchy when you change the brand of smoke weed, which most be possible is you are allergic to the brand of smoke weed that you are smoking. While if not, then you should consider whether there is something wrong with your eyes or not. Now some signs begin to occur due to smoking. Personally,you need to prepare something can help with your itchy or dry eyes, such as basic drops which works for dry eyes and itchy eyes. Everyday you can drink some warm water with honey that can help with getting rid of tired and dryness. As for me, the best thing to do is visit a doctor to seek the real reasons.