Nearly every type of chronic eye disease appears to be linked to cigarette smoking. And since smoking decreases circulation and oxygen flow to the eyes, it can also directly affect your vision. In fact, two of the leading causes of severe visual impairment and blindness - cataracts and age-related macular degeneration - are accelerated by smoking.

Smoking increases your risk of age-related macular degeneration (AMD). The macula is the part of the eye that helps you see in fine detail, and in AMD, the macula is slowly destroyed. Smoking causes damage that is thought to speed up this destruction and rob you of your vision. In fact, smoking can double to quintuple your risk of developing AMD.

Smoking increases your risk of cataracts. A cataract occurs when the lens in our eye thickens and becomes less transparent and less flexible. The lens becomes cloudy, causing vision problems. Tobacco smoke reacts with substances in the body to produce free radicals, substances that can damage our bodies' cells - including the lenses of our eyes, contributing to the risk of cataracts. For people with cataracts, as the lenses cloud, vision changes occur: blurring, faded colour perception, glare, poor night vision, double vision, reduced vision. The good news is that quitting smoking can bring your cataract risk back down almost to the same risk level as people who never smoked.

Smoking during pregnancy may harm your baby's vision. In addition to many serious health risks, a woman who smokes during pregnancy increases risk of premature birth. Infants born too early are, in turn, at risk for retinopathy of prematurity, an eye disease characterized by abnormal blood vessel growth in the eye that can progress to vision problems, including detached retina, lazy eye, crossed eyes, glaucoma, and even vision loss or blindness.

And evidence is mounting for smoking increasing the risk for other eye problems. Although more research needs to be done, smoking may increase the risk of:

  • thyroid eye disease (TED): People with hyperthyroidism (overactive thyroid) may experience TED, where their eyes protrude from the sockets, stretching the eyelids open wide. In some cases, the coordinated movement of the eyes may also be affected and cause double vision. Symptoms of TED include eye pressure, irritation and drying, and damage to the corneas. Studies have shown that smoking may increase the risk of TED or worsen existing TED. If you have thyroid disease, you should quit smoking.
  • uveitis: The uvea is a layer of tissue that is hidden from view in the middle layers of the eye. It is rich in blood vessels that carry blood to and from the eye. In a condition called uveitis, inflammation may block the flow of this nourishing blood to your eye and damage your sight. Studies have shown that smoking may increase the chances of developing uveitis.

Amy Toffelmire