Smoking, one of the biggest enemies of eyesight

Every 31 May is World No Tobacco Day, a day on which health authorities and bodies around the world warn of the dangers of smoking for our own and other people’s health. There are thousands of reasons not to start smoking or to quit if you have already taken up this harmful habit. Vision is no exception. Smoking harms your visual health, a lot.

Tobacco smoke contains thousands of chemical compounds, whereas almost a hundred are classified as carcinogens. However, although lung cancer is the biggest alarm bell when it comes to smoking, the truth is that the other ingredients in tobacco are also associated with a much higher risk of suffering from other metabolic, heart or lung diseases.

Last but not least, the chemicals added to cigarettes are not the only ones to blame for their risks. Most substances resulting from the burning of tobacco leaves are also dangerous to our health, including our eyesight. In other words, roll-your-own tobacco, pipe tobacco, cigars, etc. are also harmful, even if they come wrapped in a halo of naturalness and are free of chemicals.

Smoking and macular degeneration

La Degeneración Macular Asociada a la Edad (DMAE) es una enfermedad degenerativa caracterizada por el daño progresivo que sufre la mácula, situada en la parte central de la retina encargada de la visión central y de la agudeza visual.

Age-related macular degeneration (AMD) is a degenerative disease characterised by progressive damage to the macula, located in the central part of the retina, which is responsible for central vision and visual acuity.

The rest of the retina is responsible for peripheral vision, which is related to the visual perception of large objects. The macula, on the other hand, is essential for appreciating movement and fine details. Thus, it is essential for reading, seeing the time on a wristwatch, recognising the faces of the people around us, handling coins, distinguishing colours and their different shades, clearly differentiating small objects and so on and so forth.

The main risk factor for AMD is age, closely followed by a certain genetic predisposition. These factors are unavoidable, but that does not mean that there is nothing we can do to reduce the risk of suffering from this visual disorder. One of the main habits we can avoid in order to take care of our macula is smoking.

The reason for this is that this area of the eye is a very delicate structure, irrigated by extraordinarily fine capillaries. It is therefore easy to infer from the above that any habit that is harmful to general vascular health is also harmful to this area of the eye, given its delicate blood vessel network. Smoking promotes cellular oxidation, hardens the vascular wall, constricts blood vessels and, ultimately, has a harmful effect on the entire circulatory system, a negative effect which increases the more fragile the network of blood vessels is, as is the case in the macula.

In any case, what smokers should be aware of is that the damage caused by age-related macular degeneration is irredeemable. At present, there are treatments capable of stopping its evolution (wet form), but not of recovering the vision that has already been lost.

You should also bear in mind that AMD is listed as the main cause of legal blindness among people over the age of 50 in the Western world and is an increasingly common disease due to the growing aging population, but also to generalised bad lifestyle habits related to obesity, alcohol consumption, smoking and nutritional deficiencies.

In fact, it is a highly disabling visual disease, as it makes it difficult or impossible to perform everyday tasks, such as reading, driving, interacting with family and friends, handling money, identifying small objects, appreciating details, reading labels, etc.

“Smoking is the most important modifiable environmental risk factor associated with age-related macular degeneration. Many studies have shown that there is a higher prevalence of this disease, increased progression and worse response to treatment in patients who are active smokers. Moreover, smokers have a relative risk 2.4 times higher than non-smokers of suffering from this eye disease. If these smokers are also carriers of a genetic risk, the chances increase by up to 34 times”, argues Professor José María Ruiz Moreno, a medical director at Vissum.

Smoking and diabetic retinopathy

Likewise, smoking is one of the most important risk factors for worsening diabetic retinopathy.

This disorder is a consequence of diabetes, a metabolic disease that has a negative impact on vascular health, as a result of the alteration of the blood vessels that irrigate the retina. These alterations mean that the small capillaries become much more fragile and irregular, causing haemorrhages that can lead to significant visual disturbances.

Estas lesiones pueden ser de diferente consideración y algunas no necesitan tratamiento si se mantienen bajo control. El tabaco es uno de los factores que marca la diferencia entre una retinopatía diabética leve y controlada que no requiere intervención terapéutica y retinopatía diabética avanzada que tiene, además, un alto riesgo de complicaciones. La más frecuente es el edema macular diabético; una acumulación de líquido en la mácula que ocasiona pérdida de visión. Otra de las complicaciones que pueden aparecer en estos pacientes es la aparición de neovasos o vasos sanguíneos anormales, que pueden crecer y provocar un desprendimiento de retina o una hemorragia vítrea.

These injuries can be of varying degrees of severity and some do not need treatment, if they are kept under control. Smoking is one of the factors that makes the difference between mild and controlled diabetic retinopathy that does not require therapeutic intervention and advanced diabetic retinopathy that also features a high risk of complications. The most common is diabetic macular oedema, where fluid building up in the macula causes vision loss. Another complication that can occur in these patients is the appearance of neovessels or abnormal blood vessels, which can grow and cause retinal detachment or vitreous haemorrhage.

Smoking and cataracts

Cataracts are caused by the loss of transparency of the crystalline lens, i.e. the eye’s natural lens. Its appearance and development result in blurred vision, a kind of veil that makes everything appear in ochre or yellowish tones, whereas colours are perceived less clearly or intensely.

Although this disorder is basically linked to aging and, therefore, inevitable as we get older, the truth is that there are habits that can lead to premature opacity of this lens. Excessive and prolonged exposure to the sun without appropriate protection is one of these factors. Smoking is another one.

Cataracts can only be treated with surgery. There are no drops, treatments, exercises, contact lenses or glasses that can prevent cataracts, let alone restore lens transparency. Thus, although cataract surgery is becoming safer and more satisfying, the idea is not to undergo surgery at an age when it would be possible to see normally.

Other visual issues due to smoking

There are other visual issues related to smoking which also represent a clear incentive to stay away from cigarettes, although they do not compromise vision as seriously as AMD, diabetic retinopathy or cataracts.

One of the most common is dry eye, a condition that occurs when the eye is unable to produce enough tears to properly lubricate the ocular surface. Dry eye causes redness, irritation, discomfort and a foreign body feeling inside the eye.

On the other hand, smoking is one of the main causes of skin aging, due to its negative effect on cellular oxidation and the production of collagen and elastin, elements that are necessary for skin flexibility and firmness. This, together with its detrimental effect on tissue oxygenation and blood flow, leads to the appearance of wrinkles in the periorbital area and bags under the eyes. The solution to these issues may seem purely aesthetic, although it also involves visual aspects, especially if the eyelids droop too much. In this case, blepharoplasty is the most suitable option to solve it, as it is performed by oculoplastic surgeons who respect not only the beauty of the eye, but also its anatomy and functionality.

An array of reasons to quit smoking

For all these reasons and many more related to health at all levels, specialists insist on the need to stress messages aimed at preventing young people from starting this harmful habit and encouraging those who are already smokers to be aware of the importance of quitting as soon as possible.

The World Health Organisation and other health bodies say, however, that to achieve the Sustainable Development Goal target of reducing premature mortality from non-communicable diseases by one third by 2030, smoking control would have to be placed at the top of the agenda for governments and institutions around the world, something that does not seem to be on track so far.

To do so, countries must fight this epidemic at the highest level, which involves the formulation, implementation, enforcement and monitoring of the most effective smoking control policies, aimed at reducing the demand for tobacco. For their part, families and the public must take appropriate measures to promote their own health and that of passive smokers, while protecting children and educating adolescents to prevent them from starting to smoke.