Risk of blindness from smoking

Significant risks of retinal disease warrant patient counselling

Leigh Spielberg

Posted: Tuesday, September 1, 2020

Patients seem more likely to consider the risk of blindness as a better reason to quit smoking than the risk of dying, said Caroline Klaver MD, PhD, Rotterdam University Medical Center, the Netherlands, told delegates at the 19th Annual EURETINA Congress in Paris.

“And yet, many smokers are not aware of their habit’s risk of eye disease, so I believe it is our responsibility as ophthalmologists to inform them,” she asserted.

Dr Klaver addressed a session on the epidemiology of retinal disease. Her talk, “Risk of Blindness for Smoking”, seemed to open the eyes of many delegates regarding what role ophthalmologists could play in patient’s ocular health via smoking cessation.

Smoking is known to increase the risk of retinal arterial branch occlusions eightfold. The risks of developing both neovascular age-related macular degeneration (AMD) and geographic atrophy are clearly increased, as are the risks of developing cataract, Graves’ orbitopathy, optic neuropathy, intermediate uveitis, dry eye and floppy eyelid syndrome.

“The synergistic effect of smoking and genetic risk of AMD is particularly strong,” said Dr Klaver, increasing the risk by about 50% compared to non-smokers. Fortunately, quitting smoking can significantly decrease the risk of developing geographic atrophy when compared to patients who continue smoking, although how soon the risk decreases after quitting smoking is not known.

There are approximately 7,000 chemicals in cigarette smoke, so the potential causal pathways for smoking and eye diseases are countless. Free radicals cause damage via mitochondrial impairment, oxidative stress and inflammation. This is responsible for the increased risk of optic neuropathy, AMD and uveitis with cystoid macular oedema. Furthermore, the dioxins present in cigarette smoke promote the release of VEGF. And nicotine itself promotes both the accumulation of lipofuscin and the aggregation of platelets.

And the risks to eye health can even start before birth: maternal smoking during pregnancy increases the risk of strabismus in offspring by 50%, although the pathogenesis is unknown.

“Despite these risks, only about 40% of eye patients who smoke are aware of smoking-related eye diseases,” she said, citing a study performed by the UK National Health Service. Considering that the worldwide prevalence of smoking is 35% in males and 7% in females, the overall effect of smoking on ocular health is enormous.

The effect of e-cigarettes on eye health is not yet known, although there have been reports of acute globe rupture and corneal burns due to e-cigarette explosion. Moreover, recent reports of acute pulmonary disease and death associated with e-cigarette use provide more incentive to counsel patients on the value of quitting.