World No Tobacco Day 2022: Can Smoking Adversely Affect Your Vision? Know All About It

Smoking reduces retinal blood flow, and leads to a progression of eye diseases, says Dr. Mahipal Sachdev.

The fourth leading cause of non-communicable diseases – smoking, contributes to 53% of deaths in India. It is capable of harming nearly all the organs of the human body, including our eyes. While most people and many patients attending eye clinics recognize many adverse health hazards of tobacco smoking, they remain largely unaware of its link with blindness. Tobacco smoking is the prime modifiable risk factor for age-related macular degeneration which can lead to severe visual impairment. 

How does smoking affect the eyes? 

Cigarette smoke contains over 7000 toxins that find their way into the bloodstream. There are more than 50 compounds present in cigarette smoke that are identified as known or probable carcinogens. When cigarette smoke is inhaled, these chemicals and gases are absorbed through the lungs and transferred to the bloodstream. The carbon monoxide in cigarette smoke binds to the hemoglobin in red blood cells, preventing affected cells from carrying a full load of oxygen to cells.

Active or passive smoking promotes vasomotor dysfunction, atherogenesis, and thrombosis in multiple vascular beds. Nicotine present in tobacco and cigarettes is known to depress the body's immune system, making it harder to protect the body from illness and more difficult to heal or repair tissues. The compounds present in cigarette smoke are harmful to health, and it has been linked to a reduction in the thickness of layers in the brain, and to brain lesions, involving areas such as the area of the brain that processes vision.

Nicotine and smoking, harm the body's circulatory system, and they also damage blood vessels and neurons in the retina. Passive and active cigarette smoke can cause severe vision damage and induce eye diseases like Age-related Macular Degeneration (AMD), cataracts, and Diabetic Retinopathy. Smoking is also associated with other diseases of the eyes such as thyroid-associated ophthalmopathy, anterior ischemic optic neuropathy, and tobacco–alcohol amblyopia and is a known facilitator of diabetic and hypertensive retinopathy.

Age-Related Macular Degeneration

(AMD) is a condition in which the nerve layer of the eye-the retina, which is the main site of vision, is affected severely by accelerated degenerative changes leading to severely impaired central vision, making it difficult or impossible to read, drive and recognize faces and colors. If left untreated, AMD can lead to permanent vision loss and blindness. Cigarette smoke is high in oxidants, which deplete plasma and tissue antioxidants leading to faster degradation of the retina. Smoking causes your retinal blood vessels to constrict, which decreases blood supply to the eye and increases the risk of permanent vision loss from both the wet and dry forms of AMD. Additionally, research studies suggest that people who smoke have lower levels of macular pigments lutein and zeaxanthin, which are responsible for protecting the macula from ultraviolet (UV) radiation, which is another risk factor for AMD.

Cataracts

Cataracts are one of the leading causes of vision loss. Cataracts develop when the eye's naturally transparent lens becomes cloudy, causing blurred vision, light sensitivity, and difficulty in driving at night. Smoking increases the number of free radicals in your eyes. Free radicals are responsible for damaging the lipids and proteins in the eyes, causing lens protein to denature and coagulate leading to opacification and cataract development. While the antioxidants you consume in your diet may help to fight the free radicals, smoking can actually deplete the antioxidants and in turn, produce toxins and harmful free radicals that lead to cataract formation.

Diabetic retinopathy

Smoking increases your risk of diabetes by up to 40% — increasing your risk of diabetic retinopathy as well. Diabetes damages the tiny blood vessels in the retina, causing them to leak blood and fluid into the eye. This can even lead to hemorrhages inside the eye and retinal detachments— leading to partial or total vision loss.

Dry eye disease

At present, almost every other person is affected by dry eye disease due to a changed lifestyle and excessive screen exposure. Smoking exaggerates dry eye disease by affecting the quality of tear production and degradation of the ocular surface.

Importance of early treatment 

When one finds their vision is compromised, it is imperative to consult an eye specialist. Finding an accurate treatment plan is crucial to understanding the precautions one can take. The doctor can help restore the visual quality and prevent further loss of vision through appropriate management.
Sometimes the central vision is unaffected, and patients are unaware, but there might be changes in the periphery of the retina that can only be assessed by a thorough retinal examination by an ophthalmologist. Even if one's vision is in perfect shape and health, it is always advisable to get an annual check-up done. With age, numerous conditions may find ways to deplete the vision. Quite a number of diseases like diabetes can deplete eye health and lead to DME and Diabetic Retinopathy. 

Protecting eye vision by making lifestyle changes

Prevention is always better than cure. It is evident that the easiest way to better eye health is by taking precautions and avoiding substances that aggravate damage to eye health. Quitting smoking altogether is one of the key ways to prevent eye diseases. However, it is important to note that once the damages are done, they are not entirely reversible. Hence, even the people who quit smoking will be at risk of eye diseases. This step may be the hardest lifestyle change but quitting smoking can be a huge investment in your vision and overall health.

One must also try following a balanced diet. One aspect of the body that can change through healthy eating is your eyes! Beta-carotene, Lutein, Omega-3, Lycopene, glutathione, and Vitamin C, A, and E are some of the major antioxidants that maintain eye health. Apart from good food practices, staying hydrated, sleeping well, and leading an active life can all contribute to eye and body health.   
While it is important to make lifestyle changes, it is equally important to follow timely consultation, treatment adherence, and routine check-ups.

by Dr. Mahipal Sachdev, Chairman and Medical Director, Centre for Sight Group of Eye Hospitals, Past President All India Ophthalmological Society.

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