For the past several decades, a plethora of landmark studies have presented indisputable proof that smoking causes an epidemic of devastation, including markedly increased prevalence of lung cancer, breast cancer, GI cancer, esophageal cancer, oral cancers, and other head and neck cancers, COPD, emphysema, pulmonary hypertension, cardiovascular disease, myocardial infarctions, strokes, and the list goes on and on. Inexplicably, most in the medical community and the vast majority of lay people seemingly believe that the human eye and eyesight are immune from the scourge of smoking. This is tragically far from the truth. In fact, smoking causes a significantly increased prevalence and extent of ocular damage in all three of the leading causes of blindness in adults, namely macular degeneration, glaucoma, and diabetic retinopathy. Worse yet is that the demise in visual acuity often occurs at a younger age and in a more expedited fashion in smokers. Often overlooked is the damage afflicted by exposure to second hand smoke (SHS).
Analyzing the deleterious effects of SHS is a more difficult task because extensive variables are added to the equation such as duration of exposure, proximity to smokers, size and ventilation of room, among other factors. In the 1980’s, the International Agency for Research on Cancer (IARC) and the US Surgeon General published evidence of increased incidences of lung cancer, breast cancer, coronary heart disease, and strokes as a result of SHS. With over one billion smokers, SHS exposure is almost unavoidable for the children and adults who do not smoke and are therefore subjected to these health risks.
A direct correlation exists between the number of cigarettes smoked per day (dose) and the exhaustive list of health maladies; similarly, another direct correlation exists between the duration of smoking (in years) and these serious health consequences. The dose and duration correlations hold true for loss of eyesight from smoking as a result of macular degeneration, glaucoma, and diabetic retinopathy. Anecdotally, and epidemiologic research are now showing that SHS also causes vision loss from these same ocular diseases, albeit to a far lesser extent. A multitude of theories exist about why SHS can lead to vision loss, with one of the most common theories being that smoking markedly increases the blood level of carboxyhemoglobin. With SHS, there also is an elevated carboxyhemoglobin level in non-smokers but to a far lesser extent. For both smokers and non-smokers, the higher the carboxyhemoglobin level is elevated with SHS to varying degrees. For example, little children held by mothers who are actively smoking causes a more significantly damaging level than for a teen who is playing in his room or elsewhere in the house. A collegiate attending a hookah smoking event (but not partaking) held in a small dorm room will experience far greater carboxyhemoglobin levels than a peer sitting on the other side of an expansive lounge where the hookah smoking transpires.
While SHS induced elevation of carboxyhemoglobin will result in a reduction of the amount of oxygen reaching the retina, concurrently, the chemicals in cigarette smoke causes blood vessels to narrow and stiffen, a process known as arteriolar sclerosis, thereby further reducing the oxygen supply to the retina. In essence, retinal hypoxia results to a significant extent even with second hand smoking. Professor John Yates and colleagues at Cambridge University UK discovered that living with a smoker for five years doubles the risk of macular degeneration.
Researchers agree that SHS can lead to vision loss, however, as previously explained, due to many variable, quantify this risk is difficult. The utopian situation for all of us would be for smoking and second-hand smoke to be non-existent.
Dr Alan Mendelsohn has been working as an ophthalmologist in South Florida for the last 30 years. Should you have a question regarding your eyes or vision, please feel free to contact him at Eye Surgeons and Consultants , located at 4651 Sheridan Street, Suite 100, Hollywood, FL 33021 954-894-1500 or visit www.myeyesurgeons.com
