Effects of smoking on vision

Smoking contributes to a number of major health problems, including heart disease, stroke and cancer. But many people do not know that smoking also affects your vision. Cigarette smoke contains more than 4,000 chemicals and gases, including hydrogen cyanide, formaldehyde, carbon monoxide, and benzene. Tobacco
chemicals damage blood vessels inside the eyes. Smoking causes oxidative stress and damages the retina and further reduces the amount of oxygen that reaches the macula. Tobacco chemicals interfere with the production of tears as well.

Avoiding smoking, or taking steps to quit, lowers risk of vision impairment and vision loss. Smoking is linked to a number of eye diseases, particularly age-related macular degeneration (ARMD) and cataract, the two leading causes of blindness. Smoking has also been linked to thyroid-associated ophthalmopathy, anterior ischemic optic neuropathy, and tobacco–alcohol amblyopia and is a known facilitator of diabetic and hypertensive retinopathy.

Perhaps the most common and the most serious threat to a smoker’s eye health
is age-related macular degeneration (ARMD). This affects the macula, the part of the eye that allows you to see fine details. When the light sensitive macula breaks down, it gradually destroys a person’s central vision, the vision needed to see objects clearly and used for common daily tasks such as reading or driving, or even recognising faces. Cigarette smoking increases the risk of ARMD two to three fold, and smokers may develop the disease about 10 years earlier than non-smokers.

Like ARMD, cataracts can occur naturally with aging where the lens of the eye grows cloudy over time, leading to blurry vision, faded colours, and increased glare sensitivity. Also like ARMD, smoking significantly increases the likelihood that cataracts will develop, and at earlier ages than people who don’t smoke. Smokers double the risk of developing cataracts when compared to non-smokers. Uveitis is yet another condition that is more common in smokers than non-smokers. Uveitis is the inflammation of the uvea, the eye’s middle layer.

Uveitis harms the structures of the eye, and can lead to cataract formation, glaucoma, and retinal detachment, and vision loss. It is also well known that diabetes and its complications can affect many parts
of the eye. Diabetic retinopathy is the swelling and damage to the blood vessels of the retina related to diabetes that can result in blood leakage and other changes. If diabetic retinopathy is left untreated, blindness can result. Several factors that increase the risk of developing diabetic retinopathy include smoking, high blood pressure, drinking alcohol and pregnancy.

Tobacco smoke is also a known eye irritant and worsens dry eye — even among passive smokers — particularly for contact lens wearers. Dry eye syndrome is described as insufficient tears on the eye’s surface. Sufferers of dry eye can experience eye redness or itchiness, a ‘foreign body’ sensation and even watery
eyes. People who smoke are nearly twice as likely to have dry eyes.

Smoking is a risk factor for many other diseases that may eventually impact vision. For instance, temporary vision loss caused by transient ischemic attack or ‘mini stroke’ and Grave’s Disease, (an autoimmune disease characterised by an increase in the volume of fatty connective tissue and enlargement of muscles around the eye) are more likely to occur in smokers. In addition, fetal and infant eye disorders such as retinopathy of prematurity, strabismus or crossed eyes, refractive errors, retinal problems and optic nerve problems in babies are all associated with smoking during pregnancy.

Preventing vision loss

Healthy habits can lead to healthy eyes. The risk of eye disease and vision loss can be lowered if individuals quit smoking, eat healthy food including green leafy vegetables, fruits and food high in vitamin C, E and beta carotene, control blood pressure and cholesterol, stay active and visit an eye care professional regularly.

It’s never too late to quit smoking and enjoy the benefits of a healthier lifestyle. In order to quit smoking, enlist support from family and friends. Spend more time with your non-smoker friends and family, which may help you think of yourself as a non-smoker. Start an exercise programme, fight weight gain and your body won’t crave for nicotine effects.

In consultation with your doctors, consider nicotine replacements to help cut craving in the immediate phase after quitting. Keep yourself busy; take on new hobbies to keep your mind and body engaged.

(The writer is Consultant

Ophthalmologist, BGS

Gleneagles Global Hospitals)