How climate change can affect your eyes
Although it is easy to see the effects of climate change on the environment, changes in human health due to these environmental shifts may not be as noticeable. There are a variety of ways in which climate change can impact eye health specifically, due to increases in ultraviolet radiation to changes in the air and water. Eye irritation, burns, and increased risk of infection are just a few ways climate change can directly impact eye health.
Ultraviolet radiation and eyes
Many people are familiar with the concept of ozone depletion due to increased greenhouse gases. This depletion leads to an increase in exposure to ultraviolet radiation (UVR), which can have serious effects on our eyes.
According to a 2003 World Health Organization report entitled Climate Change and Human Health: Risks and Responses, increased UVR can lead to eye lesions (such as cataracts), “snow blindness” (sunburn on the eye), pterygium (growth of the mucous membrane that covers the white of the eye), acute photokeratitis (inflammation of the cornea) and photoconjunctivitis (inflammation of the conjunctiva), acute solar retinopathy (solar burn to the retina), macular degeneration, and a number of serious conditions.
Increased exposure to UVR can also cause premature aging of the eye’s natural lens, leading to early-onset presbyopia. This is most prevalent in populations that live close to the equator, where the sun is naturally stronger.
Furthermore, UVR-related damage can affect not only the eyeball itself but the skin of the eyelid as well. These changes can include redness of the skin, dead tissue production, lesions, and tumours.
Oxygen and the eyes
A healthy flow of oxygen to the eyes is essential for maintaining good vision. If you wear contact lenses, you might already know this, as removing your contacts before sleep is essential to letting the eyes “breathe”. Similarly, it has been demonstrated that pilots who spend time in high-altitude/low-oxygen environments have reduced night and colour vision, since oxygen is essential to power our photoreceptors.
The impact of oxygen on eye health has also been researched in marine animals. In a 50-year study ending in 2010, it was shown that oxygen levels decreased in seawater by 2%, which impacted animal metabolisms, including their vision. For animals that already live in relative darkness, a decrease in vision could be problematic, influence their behaviour, and cause birth defects, and these effects could disrupt the entire ecosystem.
Climate change can also negatively impact the quality of our water and availability of clean water supplies. Areas in the world that are already vulnerable to poor water quality will be further affected and this can directly affect the eyes. For example, trachoma (the leading cause of blindness due to bacterial infection) is spread very easily and in communities with little access to clean water. Dirty and contaminated water is also a breeding ground for water-related insect vectors that transmit diseases such as onchocerciasis – a parasitic disease which can also lead to blindness.
Considering the indispensable nature of water for hydration, cooking, basic hygiene, and cleaning, access to contaminated supplies could be detrimental to various facets of human health.
Climate change can cause erratic weather patterns, as well as both increases and decreases in typical temperatures. In those areas where temperatures are rising, we could see an increase in symptoms in people prone to dry eyes in the coming years. These increases in temperature could also cause an increase in forest fires if the air is dry enough. In turn, smoke from these fires can cause eye irritation (especially among contact lens wearers and those with allergies), and even gum up the surface of the eyes.
What’s more, exposure to traffic-related air pollution means we are regularly exposed to ambient nitrogen dioxide and carbon monoxide, which can lead to an increased risk in age-related macular degeneration (AMD), according to an 11-year study of almost 40,000 Taiwanese residents. AMD causes severe and sometimes permanent loss of central vision, usually in people aged 60 and over.