Dry Eye Dx and Tx
The Effects of Smoking on the Ocular Surface
By Katherine M. Mastrota, MS, OD, FAAO
In 1964, the first U.S. Surgeon General's report on the detrimental effects of smoking on health was released. It was 386 pages. Extensive data gathered subsequent to this initial report substantiate the negative impact of smoking. “How Tobacco Smoke Causes Disease, The Biology and Behavioral Basis for Smoking-Attributable Disease,” a 704-page report of the U.S. Surgeon General, was published in 2010 by the U.S. Department of Health and Human Services. Scientific evidence supports the conclusion that inhaling the complex chemical mixture of combustion compounds in tobacco smoke causes adverse health outcomes, particularly cancer and cardiac and pulmonary disease, through multiple defined mechanisms that include DNA damage, inflammation, and oxidative stress.
What is not reviewed in this document are the deleterious effects of cigarette smoking on the ocular surface and its impact on dry eye.
Smoke and the Ocular Surface
Multiple studies suggest that cigarette smoking/cigarette smoke poses a significant challenge to the homeostasis of the ocular surface. In a 3,722-subject cohort, Moss et al (2000) found a nearly two-fold increase in the odds for dry eye among smokers.
Furthermore, independent studies demonstrate that smoking alters components of the tear film. Smokers have a reduced tear film breakup time and reduced basal tear secretion. Matsumoto et al (2008) reported that conjunctival impression cytology revealed a significant loss of goblet cells and squamous metaplasia in habit smokers. Brush cytology showed conjunctival neutrophil infiltration in smoker subjects in the same study. These authors and others document the negative changes of tear film lipid quality and spread. Smokers exhibit altered lipids, a reduced rate of lipid spread, and an increased tear film evaporation rate. Additionally, tear protein patterns, analyzed via electrophoresis, are changed in smokers as compared to non-smokers, correlating with an increase in dry eye-related symptoms.
Compromised corneal sensitivity is considered core to pathogenesis of ocular surface disease. Considering the aforementioned, it is not surprising to learn that corneal sensitivity in smokers is impaired (Satici et al, 2003).
The deleterious effects of cigarette smoking are not confined to smokers. Secondhand smoke (also called environmental tobacco smoke, involuntary smoke, and passive smoke) is the smoke given off by a burning tobacco product and the smoke exhaled by a smoker. The National Cancer Institute's Fact Sheet on Secondhand Smoke notes that there is no safe level of exposure, with even low levels of secondhand smoke being harmful. The Johnson & Johnson Ocular Surface and Visual Optics Department at the Keio University of Medicine in Japan investigated the effects of acute passive cigarette smoke exposure on the ocular surface and tear film in healthy non-smokers and found that even after brief passive exposure, adverse effects on ocular surface health were evidenced by an increase of tear inflammatory cytokines, tear instability, and damage to the ocular surface epithelia.
In 2009, the Centers for Disease Control estimated that 46 million people, 20.6 percent of adults in the United States, smoked cigarettes. Is one of these your dry eye patient? CLS
To obtain references for this article, please visit http://www.clspectrum.com/references.asp and click on document #189.
Dr. Mastrota is secretary of the Ocular Surface Society of Optometry (OSSO). She is center director at the New York Office of Omni Eye Services and is a consultant to Allergan, B+L, Noble Vision, Ista Pharmaceuticals, and Cynacon Ocusoft. You can reach her at firstname.lastname@example.org.