Don’t let smoke blind you

Environmental toxins, which are generated inside our homes, contribute largely to women developing cataract early in life. Those who do not have a proper ventilation system or outlets for the smoke arising from cooking are at great risk as their eyes can get affected badly. Prolonged exposure over the years is found to cause this problem, explains Dr A.K. Grover, chairman of the ophthalmology department at Sir Ganga Ram Hospital.

How do environmental toxins influence the eyes?
Prolonged exposure to harmful toxic compounds in the environment causes irritation in the eyes. The smoke released from burning substances like charcoal, wood, biomass and burning of unrefined cooking oil at high temperatures, and even smoking, contains many kinds of chemical products, including particulate matter, carcinogens, carbon monoxide, hydrocarbons and metal ions. These toxins and pollutants may be absorbed by the eyes, possibly damaging the lens by causing oxidative changes, which may lead to cataract formation, among other eye ailments.

Which toxins harm the eyes? Do they come from air pollution or home pollution? 
Studies have reported that indoor pollution, which includes smoke emitted from solid fuel combustion, may act as an independent risk factor of causing cataract. Indoor pollution may also include various mixtures of chemicals present in modern buildings. Some of the common toxins emitted by wood smoke or solid fuel smoke contain carbon monoxide, hydrocarbons, benzene and formaldehyde among many others, including carcinogens. There are not many studies present on the effects of outdoor pollution influencing the incidence of cataract. However, the environmental toxins around photochemical, coal-based industries, or other such industries and factories affect the eyes of the people working there.

How do the toxins cause cataract? 
Getting exposed to these environmental toxins at homes from an early age and prolonged exposure over a period of time increase the chances of these pollutants getting absorbed and causing oxidative changes within the eyes, affecting the natural lenses. Hence, early and prolonged exposure may have significant influence in causing early cataract.

Who are exposed to these toxins?
According to the WHO, around 300 crore people all over the world use solid fuels like biomass and coal, either for cooking or heating their homes. Also, there is good evidence that the combustion of solid fuel for cooking may be associated with cataract formation, especially in developing countries such as India and Nepal. In India, many homes lack a proper chimney system as well as ventilation.  While ambient or outdoor air quality does cause eye irritation, due to lack of research findings, the impact of outdoor pollution on cataract cannot be confirmed. 

Long-term influence leads to this problem. Which would mean how many years? 
The time duration of developing cataract cannot be ascertained or predicted. Cataracts are of many kinds, are influenced by various factors and can develop slowly or rapidly. 

What are the preventive steps that must be taken? 
Cataract cannot be prevented but with advanced technology, it can be treated easily with good outcomes. However, by regulating the risk factors, the onset of cataract can be delayed. Some of the common measures would include having antioxidants-rich diet, controlling risk factors that lead to diabetes and hypertension, shielding eyes from UV rays and pollutants, not smoking and employing  good eye care practices, which includes going for regular health check-ups.

How can people at risk be protected? 
The measures to protect people, especially women, from developing cataract due to indoor pollution would include spreading public awareness about the adverse effects of solid fuels, providing them better and cleaner fuel alternatives such as gobar gas, LPG, etc., offering better designs of cooking stoves that are smokeless and fuel efficient and emphasising on ventilation and the use of chimneys.