Most people know that smoking causes lung cancer, but not many realise that it can also cause blindness. Smokers are up to four times more likely than non-smokers to develop age-related macular degeneration (AMD) and smokers with a genetic predisposition to AMD are 20 times more likely to get the condition.
Smoking is the biggest ‘modifiable’ risk factor for AMD; by stopping smoking you will reduce your chance of getting the condition and your chances of it progressing. There is also evidence that smokers being treated for wet AMD do not respond as well to treatment as non-smokers. Passive smoking can also increase the risk of developing the condition.
Cigarette smoke contains 4,700 chemicals, which are extremely toxic. Repeatedly exposing delicate retinal cells to these oxidants effectively fast-forwards the ageing process. At the same time as increasing oxidant levels in the body, smoking decreases the levels of antioxidants and therefore reduces the body’s ability to protect itself.
Smoking also causes the blood vessels to narrow. This affects the blood vessels to the eye and increases overall blood pressure, which is another risk factor for macular degeneration.
Some research suggests that smokers have lower levels of the macular pigments lutein and zeaxanthin, which are thought to protect the macula from the damaging effects of sunlight.