The Risk of Smoking to Vision
By
J.L. Gayton, MD

Many people think about the effects that smoking has on the cardiovascular system and the respiratory system. Smoking also has a detrimental effect on the visual system. In fact of the most five common causes of blindness, smoking has a negative impact on all five. Smoking, because of its scavenging of antioxidants, increases the risks of cataract development. Because of its negative impact on diabetes, it increases the risk of diabetic retinopathy. Due to its negative impact on the circulatory system, it makes individuals more susceptible to glaucomatous field loss. This is due to the decrease in the nutritional supply to the optic nerve and nerve fiber layer. Obviously, smoking has a negative impact on the various ischemic optic nerve conditions by decreasing the blood supply to the optic nerve. Smoking also makes a person more likely to have vascular occlusions; both the arterial and venous variety. Vein occlusions are more likely due to the increased blood pressure and increased blood viscosity. Arterial occlusions are more likely due to hypertension, increased blood viscosity, and narrowing of the vascular lumens.

The number one cause of vision loss in people over the age of 50 is age-related macular degeneration. There is a lot of research that indicates that smoking plays a significant role in the development of age-related macular degeneration. Although, the wet type of macular degeneration (associated with bleeding) only accounts for 10% of macular degeneration cases, it accounts for 90% of the blindness contributed to macular degeneration. According to the world health organization, smoking is one of the most dangerous individual risk factors in the development of macular degeneration. In an ongoing European study, smokers have up to a 2.5% greater risk of developing neovascular macular degeneration compared to people who have never smoked and a 4.8% higher risk of developing geographic atrophy. The risks are reduced in ex-smokers, but only 20 years after they have quit.

There are numerous toxic chemicals in cigarette smoke. According to Dr. Scott Cousins of the Bascom Palmer Eye Institute, one of these chemicals is hydroquinone. It is present in high levels in smokers and causes direct oxidation and injury to the retinal pigment epithelium. It blocks the degradation of this pigment epithelium such to show that a matrix synthesis outpatient degradation deposit formation begins. These deposits then form what are known as macular drusen. Another harmful ingredient is nicotine. Nicotine causes cell mitosis in vascular smooth muscle and endothelium. This promotes larger and more severe neovascular lesions which obviously plays a role in wet macular degeneration. Dr. Ivan Suňer of Bascom Palmer Eye Institute states “cigarette smoke also may activate macrophages and that activated macrophages may trigger progression in dry to wet macular degeneration”. Dr. Paul Mitchell at the University of Sidney Australia states “the two dominant risk factors for macular degeneration are genetics and smoking. Smokers develop macular degeneration 6-10 years earlier than non-smokers”. Dr. Mitchell also states “smoking may cause or contribute to up to 20% of new blindness in people over the age of 50. Over ¼ of macular degeneration cases causing blindness are attributable to past or current smoking”. Dr. Scott Cousins states “patients with active neovascularization should not smoke at all”. Dr. Anthony Alberg of John Hopkins University states “second hand smoke exposure also associated with significant reduction in antioxidants that play a role in preventing macular degeneration”.

Another study that pulled several different analyses, the Beaver Dam eye study in the United States, the Rotterdam eye study in Europe, and the Blue Mountain eye study in Australia, identified a significant association between smoking and age-related macular degeneration. Using people who have never smoked as a reference group, the pooled analysis found current smokers have a 300 fold increased risk of macular degeneration. The risk remained elevated for past smokers, but was decreased relative to the risk of current smokers. Compared to persons that have never smoked, those who had quit smoking had a 30% increased risk for macular degeneration.

Smoking does not just affect selective organ symptoms. Smoking affects the total body. In fact, men who smoke 20 or more cigarettes a day are almost 40% more likely to be impotent than those who do not. Researchers have found that there is a very strong link between the number cigarettes smoked and the level of difficulty in achieving erection. Even smoking 20 or fewer cigarettes a day makes a man 24% more likely to have erection difficulties than those who do not smoke at all. So, smoking is bad for your health, vision, finances, and sex life.