Some eye conditions (obstruction of retinal vessels, maculopathy, cataracts, etc.) are much more common in smokers and occur at an earlier age than in non-smokers. Older smokers also have a higher risk of developing increased eye pressure (intraocular pressure) as compared to non-smokers, but there is no evidence that smoking itself is a risk factor for glaucomatous damage.
Even though marijuana does decrease the intraocular pressure, its medical use has not yet been investigated to the extent that it can be recommended as a therapeutic drug. Very few controlled studies have been performed; the advantages and disadvantages of long-term treatment need to be rigorously assessed.