Saving sight in the tobacco pandemic.

Dear Editor, We read with interest the insightful editorial on “Singapore and the Tobacco Pandemic” by Lim.1 We share the author’s view that an effective smoking cessation programme, which reconciles evidence-based interventional strategies with real-world clinical practice, is essential in our drive towards a “Nation of non-smokers”. However, it should also be emphasised that effective education of patients on the ills of tobacco use can often provide them with the initial impetus to quit smoking. Epidemiologic data over the past decades have established cigarette smoking as a major preventable risk factor for many cardiovascular, respiratory and malignant diseases. Comparatively, the association between smoking and ocular diseases is less widely known. There has long been compelling evidence of the link between smoking and age-related eye diseases such as cataract and age-related macular degeneration (AMD), 2 leading causes of blindness and visual impairment worldwide.2 Studies have found that smokers are up to 3 times more likely to develop nuclear sclerotic type cataract than non-smokers. The risk of cataract development is further increased with the number of pack-years smoked.2 Similarly, smoking increases the risk of AMD and its subtypes. It is, in fact, the most important modifiable risk factor of AMD. Both previous and current smokers are at risk of developing AMD 5 to 10 years earlier than nonsmokers, respectively.3 Male smokers may be at higher risks of developing non-exudative AMD, whilst female smokers are more likely to progress to advanced AMD.2 Very recently, in line with findings in western populations, the Singapore Malay Eye Study (SiMES) also found that current smokers were significantly more likely to have late AMD [odds ratio (OR), 3.79]. This association was strongest among those who currently smoked more than 5 packs of cigarettes per week (OR, 9.35).4 Cigarette smoking induces tissue ischaemia and accelerates atherosclerosis through various biochemical and cellular mechanisms. The deleterious effects of smoking on systemic vasculature and blood flow as seen in coronary artery disease and cerebrovascular disease are also implicated in many ischaemic and thromboembolic diseases of the eye. Studies have suggested an increased risk of retinal ischaemia, amaurosis fugax, anterior ischaemic optic neuropathy and idiopathic ophthalmoplegia with smoking, mainly attributed to smoking-induced ischaemia Saving Sight in the Tobacco Pandemic