Climate Change and Impact Of Pollution On Eyes
By Dr. Himanshu Shekhar, Group Chief Strategy & Clinical Officer, ASG Eye Hospital
2025 was 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.
Dr. Himanshu Shekhar, Group Chief Strategy & Clinical Officer, ASG Eye Hospital
Cataract - Pollution, UV, and heat accelerate lens ageing
The lens of the eye is normally crystal-clear. To stay transparent, the lens relies on stable protein structure, tight water balance, and antioxidant defences that protect against oxidative damage.
The lens has limited regenerative capacity; damaged proteins tend to accumulate. A cataract is a progressive clouding of the eye’s natural lens that reduces the clarity of the image reaching the retina. Cataracts are treated by cataract surgery with removal of the opaque lens and implantation of an intraocular lens.
Heat does not usually “harm” the lens in everyday life, but sustained exposure to high environmental heat and infrared radiation, particularly in certain occupations, can raise intraocular temperatures and stress lens proteins. Radiant energy can be absorbed and converted into heat in ocular tissues, and this rising temperature increases the risk. Lens proteins are sensitive to oxidative stress. ‘
Pollution can also contribute by increasing systemic and local oxidative burden and by increasing the inflammation, which can accelerate age-related tissue changes. Over time, the lens becomes less able to maintain protein stability and clarity, increasing the likelihood of opacification.
Keratitis or Inflamed Cornea
Keratitis means inflammation of the cornea, the clear front “window” of the eye. It ranges from mild surface inflammation to rapidly progressive, vision-threatening infection. Climate-linked exposures matter here because the cornea is the first point of contact for heat, dust, smoke, allergens, and microbes.
Air Pollution
Air pollution can destabilize the tear film and irritate the ocular surface, causing micro-abrasions and epithelial disruption. This weakens the cornea and makes it more vulnerable to inflammation and secondary infection.
How chronic pollution exposure can contribute to nutritional deficiencies
The eye is also affected by direct contact with polluted air, and long-term pollution exposure effects eye nutrition in ways that matter for ocular resilience. Air leads to oxidative stress and inflammation in the body. When oxidative stress is chronically elevated, the body draws more heavily on antioxidant nutrients (such as vitamins A, C, and E, and trace elements like zinc and selenium) that help neutralize reactive species.
While vitamin D is not an “eye vitamin” in the narrow sense, deficiency can be a marker of reduced sunlight biology and broader health vulnerability, and it’s deficiency commonly coexists with indoor lifestyles that also increase screen exposure and dry-eye symptoms.
Collectively, all stakeholders, from the government to public and private healthcare players must come together to manage these environmental transitions that impact overall health, especially eye health. Climate change and the effects that rapid economic development brings with it, cannot be ignored. The way forward must then be a more policy oriented inclusive approach that works towards the creation of systems where AQI and UV index monitoring systems have more measurable outcomes in medical records of patients.
Besides this, ways can also be assessed to expand the National Programme for Control of Blindness and Visual Impairment, to include surface level diseases brought on by climate changes. We can work towards ensuring that anti inflammatory tools are affordable, such as cataract screenings. This can be encouraged by public private partnerships. Essentially, ways such as these can help quantify the impacts of pollution on eyes, and thus we can try and put a number to it, and find addressable ways to reduce its impact. The result will be a holistic approach that focuses on broad ESG frameworks that encompass not only clinical but also socio economic impact.
A World Bank study notes that Due to its convergence with climate change, India has already put in motion many of the essential “sector transitions” needed in air quality management. For example, India is spearheading a solar-energy revolution. Today, 60 percent of Delhi Metro’s daytime energy requirement is being met through solar power from the 750 MW Rewa Solar Project in Madhya Pradesh, reducing its dependence on coal, as well as saving over $170 million on its energy bill over the next 25 years.
A study by the World Bank and the International Institute for Applied Systems Analysis (IIASA) show that focusing on air pollution through a clean air pathway out to 2030 could bring about significant climate change co-benefits for India. Such a pathway, for example, will reduce India’s CO2 emissions by 23 percent by 2030, and 42 percent by 2040-50.
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