New research reveals how climate change is affecting our eyes. In addition to well-known factors such as UV radiation, genetics and aging, which can lead to cataracts, which affect around 94 millions of people, researchers have discovered another contributing factor in recent years: climate change. Cataracts are a condition in which the lens of the eye becomes cloudy, causing blurred vision.

Climate change increases the risk of eye disease in several ways. First, it makes the planet worse off. High temperatures can damage the eye's natural defense systems, which normally fight the buildup of harmful molecules called reactive oxygen species. These molecules can damage the crystalline proteins in the eye’s lens, which must stay organized to keep the lens clear. Damage to these proteins by reactive oxygen species leads to the formation of clouds that cause cataracts. Because the lens cannot regenerate these proteins, the more time a person spends in the heat, the greater the risk of developing cataracts. A 10-year study in southern Spain found that for every degree Celsius increase in the maximum average annual temperature, there were 370.8 additional cases of cataracts per 100,000 inhabitants. Although the typical age of onset of cataracts is 60 years or older, in regions with a high proportion of the population working in agriculture, cataracts were more common in people aged 15 to 49. An example is farmer Alka Kamble from India, who worked for decades in scorching heat without sunglasses or shade, which likely contributed to her deteriorating eyesight and cataracts.

Another way global warming contributes to eye disorders is increasing our exposure to UV rays. Part of this is due to behavior—people tend to spend more time outdoors when it’s warm. But in some places, like Southern California and the Costa del Sol in Spain, hot, dry winds suck water vapor out of the air that would normally absorb UV radiation, causing more UV exposure. UV radiation also creates reactive oxygen species that damage the lens of the eye, and can directly damage the DNA of lens cells.

In addition to cataracts, climate change also causes increase in other eye conditions, including inflammation of the cornea (keratitis), pterygium (growth of fleshy tissue on the white part of the eye), and conjunctivitis (inflammation of the conjunctiva). Rising heat, pollution, and airborne allergens—driven by climate change—can contribute to a range of eye disorders, from infections and inflammation to cataracts. A 2023 study found that temperatures exceeding 82°F (28.7°C) increased the risk of conjunctivitis by about 16 percent, compared with temperatures around 50°F (10.7°C). Longer pollen seasons and increased mold growth associated with climate change are also contributing to the rise in allergic conjunctivitis.

In addition to these direct impacts, climatic droughts cause lack of food security, which can lead to a lack of essential nutrients that threatens damage to the optic nerve. During droughts, people are often forced to use unsafe water, which also increases the risk of eye infections.

There are ways to protect your eyes from climate-related damage. Outdoor workers should ensure they have adequate shade and take frequent breaks to cool down. Wearing a hat with a brim to protect their eyes and sunglasses with UV protection, which offer up to 38 percent more protection, are also recommended. Contact lenses containing hydrogel, which allows more oxygen to reach the cornea, can also help. Eating foods rich in vitamins A, C, and E and tryptophan, as well as avoiding smoking and alcohol, can also help. Reducing greenhouse gases and ozone-depleting substances is key to protecting eye health globally. Even under the best-case climate scenarios, however, intense heat, drought, and other eye irritants will continue to affect people. Some programs, such as India’s National Programme for the Control of Blindness and Visual Impairment, are trying to address the problem by providing affordable cataract surgery, which is what helped Alka Kamble. Spring