The smoking will cause the dilated eyes because of the inner stimulating irritates. It is harmful for the eyes which will let the eyes easily get infection and inflammation. In addition, smoking is bad for the body health which may let you easily choke. In a word, you should better not smoke to protect the body and eyes.
Well, yes, smoking can lead to dilated pupils. And there are many people who suffer from the symptom because of smoking. First, you should know that dilate pupils are often caused by high blood pressure. So if you keep smoking, your blood pressure can be very high, it can affect your eyes, and then lead to dilate pupils. So in my opinion, you should quit smoking. Also, hyperventilation, muscle tensions, which are the most common causes to dilated pupils. By the way, smoking can not only affect your eyes, but also, it can damage your body organ, and then do harm to your health. So just give up it.
Well, it seems that you like to smoke weed from time to time. Anyway, it is not a healthy habits which could give rise to a lot of problems. As far as I know, there are several factors involved in leading to dilated pupils, one of them is the use of drugs, so you know weed is a drug, so smoking weed would surely generate dilated pupils. So, I advise you to quit the habit and find an alternative to satisfy your needs.