Heroin addiction is a concerning phenomenon rising day by day and with each case we see how it affects our overall health. From our respiratory organs to our heart Heroin can claim most of our body with its deadly side effects. Heroin users often have seen changes in their eyes, especially the pupils. A study says that the reason behind changes in one’s pupil size can be explained by how long they have used Heroin. So does Heroin really change our pupil size? If yes let us find out does Heroin dilate pupils or makes them smaller in this blog.