Kritika Gautam, B. Optom

Optometrist, Dr. Shroff’s Charity Eye Hospital, New Delhi, India

 

Keywords: Climate Change, Eye Health, Environment

Human activities are the primary cause of global climate change. Human disruptive behaviours for empirical development contributing towards increment of global temperature, ozone layer depletion, and increasing medical and hazardous waste are affecting the climate in some or other ways.

Human health is significantly impacted by climate change because it affects the food we eat, the water we drink, and the air we breathe in one way or another (1). These days, it’s a worldwide emergency that affects people locally, nationally, and globally.

While the effects of climate change on respiratory and cardiac conditions are well known, the effects on the eyes are less well understood.

Climate Changes and Eye Health

Any environmental changes can affect the eye as they are exposed directly to the environment.

UV Rays: Depletion of the Ozone layer results in overexposure to UV rays, prolonged exposure to UV lights can cause vision-threatening eye problems.

UVA: Low-energy radiation that has the potential to damage the macula. If unprotected, this could be detrimental to one’s central vision.

UVB: Damages the tissue in the shallow area of the eye, affecting the cornea and lens. It is often considered the more dangerous of the two types of ultraviolet light. (2)

The common damage results due to UV rays are-

    • Photokeratitis burns to the corneal surface due to exposure of UV rays that occur in reflective environments such as sand, snow, or waterbodies.
    • Cataract, as per the reports 20% of cataract cases are due to UV radiation overexposure. (3)
    • Pterygium and Pinguecula, According to WHO 42-74% of pterygium cause is solar radiation. (4)
    • Macular Degeneration, UV rays contribute to degeneration of macula with age.
    • Retinal Detachment, Nathalie Auger et al. reported the increased risk of retinal detachment with elevated outdoor temperatures. (5)
  1. Smoke fog or Smog: Delhi has been covered in a heavy layer of smog for the past few days. The city’s Air Quality Index spiked 100 times poor according to WHO. Dr Bhupesh Singh et al. reported that small particulates of smaller than 2.5 microns can easily permeate the cornea and cause redness, grittiness, and irritation (6).
  2. Low Humidity: A humidity level of 45% or higher on average is good for eye health. Dry environments reduce lipid layer thickness and increase tear evaporation rates. Consequently, the eye’s surface may dry out more quickly. (7)The spread of acute trachoma is the leading cause of infectious blindness.  less common at higher elevations has been reported in several studies, suggesting that temperature may have an impact on the spread of trachoma. (8)
  3. Precipitation: Communities may be more vulnerable to various pathogens that have an impact on the eyes if there is an increase in floodwater combined with inadequate drainage infrastructure. According to one such study, the greatest known outbreak of toxoplasmosis (which is responsible for retinochoroiditis) in French Guiana happened following an atypical flood with warm weather, which may have contributed to the outbreak’s magnitude. Additional pathogens connected to flood-related outbreaks include keratitis caused by Acanthamoeba. (9)

Ways to protect eye health due to climate change

  • Avoiding the exposure to harmful pollutants
  • Washing hands can help in reducing infected ocular conditions
  • Wear protective glass outdoors
  • Regular eye checkups

The majority of programs that discuss how climate change is affecting health do not address eye health because little is known about how particulate matter in the air causes long-term inflammation of the eyes. Preventing detrimental effects on the eyes would be better served by the most effective eye health care.

 

References:

  1. “Climate change and Human Health”, United States Environmental Protection Agency (1)
  2. Baptist Eye surgeon, “5 ways UV Rays Damage your eyes and Vision, 2020 (2)
  3. Praveen Vashisth, “Association of cataract and sun exposure in geographically diverse populations of India: The CASE study. First Report of the ICMR-EYE SEE Study Group” 2020 (3)
  4. Mohammad Satchi, “Prevalence and risk factors of pterygium: a systematic review and meta-analysis”, Survey of Ophthalmology 2018 (4)
  5. David Steel et al., “Retinal Detachment”, National Library of Medicine, 2014 (5)
  6. Article, Hannah Ellis Petersen, “Delhi air pollution spikes to 100 times   WHO health limit” 2023 (6)
  7. Sonia Kelley, “How climate, humidity and environmental factors may affect eyes and vision” (7)
  8. Anita Ramesh et al., The Impact of Climatic Risk Factors on the Prevalence, Distribution, and Severity of Acute and Chronic Trachoma (8)
  9. Romain Blaizot et al., Outbreak of Amazonian Toxoplasmosis: A One Health Investigation in a Remote Amerindian Community, 2020 (9)