Climate Change and Impact Of Pollution On Eyes
2025 has been a year of many firsts, including some very defining global environmental impacts, right from the EU updating its climate pledge, to the formation of the first set of carbon market rules, to COP30 which saw countries agree on tripling climate finance for developing countries.
It is often recognised that developing countries need to attain certain levels of economic growth before they can factor in environmental impact in their GDP. The short term trade off can seem to offset the longer term development story- as seen in the latest AQI levels in Delhi, repeatedly breaching the 700 mark.
AQI, a measure of our air quality, has been particularly bad this year, exacerbated by high pollution levels, smog, heavy fog and road and infrastructure development. As with all development that can be measured, it is worth taking a look at what impact pollution causes to eyes.
A 2019 study published in The Lancet Planetary Health estimated that lost output from premature deaths and illnesses (morbidity) due to air pollution amounted to about $36.8 billion, or 1.36% of India’s GDP that year. Besides overall health, air pollution has a direct impact on the eyes, the most exposed part to direct pollutants.
Studies have shown that extremes in temperature and weather events affect the surface of the eye and increase the risk of disease, inflammation, and infection. Climate-linked exposures like dust, smoke, and pollutants destabilize the tear film and cause micro-abrasions that weaken the corneal epithelium.
Air pollution, especially fine particulate matter PM2.5 and PM10 and irritant gases can affect the tear film that covers the cornea and sclera. It can cause inflammation of the conjunctiva, and reduce the corneal epithelium’s protective barrier. Large population and clinical studies link higher particulate exposure with dry-eye and ocular surface inflammation. This pattern of “dryness with inflammation” causes symptoms such as burning, gritty sensation, redness, watering of eyes, and fluctuating vision during hot, dusty, or smoky periods. Heat and low humidity increase evaporation of tears leading to concentration of salts in the tear film. This increases “friction” during blinking.
Increased UV exposure can also increase risk of developing cataracts and other eye damage, and sun protection is recommended when the UV Index is 3 or above. High-dose UV can also cause acute photokeratitis, which is essentially a sunburn of the cornea. This is intensely painful but preventable.