Smoke from marijuana has no effect on the lungs

That's not a claim that science would make, you can't prove a negative. Absence of evidence is not evidence of absence.

It does reduce intraocular pressure but only temporarily, so smoking cannabis not actually a great treatment for glaucoma, it only reduces the pressure for a few minutes after smoking so its benefits for glaucoma are exaggerated.

That said cannabis in various forms, especially not smoked, is great for a wide variety of diseases that are probably caused by cannabis deficiency. I was reading something that pointed out that animals would have been eating feed that included hemp and that people would get their CBD that way.