Smoking

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.

Marijuana

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.