We have all heard or seen the surgeon general’s warning about smoking: it causes lung cancer, heart disease, emphysema, and may complicate pregnancy. But fewer people know that it also plays a significant, negative role in eye health.

Recent studies have pointed to smoking as a contributor to age-related macular degeneration, the leading cause of blindness in persons 65 and older. Smokers also have a three-times greater risk of developing cataracts.

The chemicals in cigarette smoke get into the bloodstream, cause clots, and shrink blood vessels. The retina uses a major supply of blood to help us see clearly. When the retinal receptors lack a proper flow of blood, damage occurs that directly affects eyesight. This constriction of blood vessels also raises inner eye pressure, resulting in glaucoma and deterioration of the optic nerve.

Other eye disorders attributed to smoking include uveitis, an inflammation of the middle layer of the eye and Graves’ ophthalmopathy, a thyroid-related disease that disrupts muscle control of the eye. Smoking worsens diabetic retinopathy, blood vessel damage associated with abnormal sugar levels and spikes the number of free radicals, molecules in the body that alter healthy cells. This changes the ability to absorb proper nutrients and vitamins—including those necessary for eye health.

Contact lens wearers who also smoke exacerbate conditions of dry eye and cornea irritation, increasing the chances of infection. Achieving comfort becomes more difficult, and smokers have to resort to additional dietary nutrients, supplements, or medicated drops to increase eye moisture. Quitting the habit gives you the opportunity to see if your dry eyes improve to the point where you can do away with those ‘artificial tears’ and other lubricants.

Second hand smoke has over 250 toxic compounds that are left behind in the air for eyes to be exposed to. In addition to the obvious irritation, second hand smoke gets into the bloodstream just as pervasively as puffing from a lit cigarette.

Quitting smoking reduces the risks of developing eye disease, but once you are diagnosed with macular degeneration or optic nerve damage it is irreversible. The key is to give up smoking while eyes are relatively healthy with no major disorders present; risk factors continue to decline the longer you stay away from cigarettes.

Snuffing out the habit sooner rather than later is a winning health strategy. Not only will you breathe easier and enjoy your activities more, but you will also give yourself a great chance of keeping good vision along with a better quality of life.