Emerging research underscores a concerning trend: the rising incidence of cataracts appears to be intricately linked to environmental changes, particularly rising temperatures and air pollution. As global temperatures climb and pollution levels fluctuate, new data from Spain published in Environment reveal how these shifts are affecting eye health, especially among aging populations.
One of the most significant findings from the study is the strong correlation between increasing maximum temperatures and the rise in senile cataracts—cataracts occurring in individuals over 60 years of age. Specifically, for every one-degree Celsius increase in the annually averaged maximum temperature, an estimated 370.8 additional cataract cases were observed. This aligns with data from China, where a 4% increase in elderly cataracts was noted for each degree of temperature rise. Heat waves, in particular, may further intensify this correlation, highlighting the potential role of thermal stress in accelerating lens opacity.
Humidity and rainfall, on the other hand, demonstrate a protective effect. While the protective role of humidity was only modest in the Chinese cohort, with a 1.4% risk reduction per percentage point increase in humidity, the Spanish study found a much stronger inverse relationship with annual rainfall. Areas with higher rainfall—typically inland and at higher altitudes—exhibited significantly fewer cataract cases. In coastal areas, where rainfall is lower and temperatures higher, the incidence was disproportionately high, suggesting a geographical gradient influenced by climate.
When shifting the focus to early cataracts (in individuals under 60), the picture becomes more complex. Unlike senile cataracts, early cataracts did not display a strong temporal correlation with temperature, humidity, or rainfall. Instead, multiple interacting factors appear to be at play. Air pollutants—particularly fine particulate matter (PM2.5 and PM10), carbon monoxide (CO), and nitrous oxide (N₂O)—were moderately to strongly associated with higher incidence rates, especially among men. These pollutants are typically associated with industrial emissions, agricultural activity, and vehicular exhaust.
Interestingly, the study employed cluster analysis to better understand these multifactorial relationships. This method revealed that early cataracts in both men and women were closely linked not only to environmental variables like maximum temperature and sunshine but also to socioeconomic factors such as employment in the agricultural and service sectors.
Cataracts, once largely attributed to aging, are now emerging as environmentally sensitive conditions. The findings call for targeted interventions—such as pollution control, occupational health measures, and increased access to ophthalmologic care in high-risk regions. As global temperatures continue to rise and pollution remains a persistent issue, proactive strategies will be essential to mitigate the growing burden of cataract-related visual impairment.
Sources: Environment
