EXTREME WEATHER EVENTS AND GLAUCOMA

 

Extreme weather events (EWEs) (e.g., heatwaves and cold spells) are reportedly associated with high morbidity through various physiological mechanisms. Similarly, extreme heat and cold temperatures also affect the structure and function of the eye and vision. EWEs are significantly associated with increased glaucoma prevalence, and the risk of glaucoma increases with the intensity of heat waves and cold spells.

Another risk factor for the development of glaucoma and diabetic retinopathy based on the Rural Epidemiology for Glaucoma (REG-China) study is long-term exposure to air pollution.[1,2]

A study by Zhang et al has reported on the impact of heatwaves and cold spells on glaucoma in rural China, through a national cross‑sectional study. The REG-China study was conducted in ten provinces of China, and 36,081 adults aged 40 years or more were included.[3]

The study found that glaucoma was more strongly affected by heat waves than by cold spells. The effects of both heat waves and cold spells were higher in males than females and in smokers than nonsmokers.

Overall, the risk of glaucoma in general, PACG, and POAG increased with the intensity of heat waves and cold spells.

Those with a family history of glaucoma were more sensitive to cold spells.

Higher heatwaves were significantly correlated with a higher odds ratio (OR) of glaucoma, with the OR (95% CI) ranging from 1.014 (1.009, 1.018) to 1.090 (1.065, 1.115) by different definitions. This study found that in heatwaves, mean daily temperatures above the 95th percentile (HW15) for more than four consecutive days had the highest risk for glaucoma.

Higher ambient temperature is a risk factor for the development of glaucoma. However, some studies have shown that IOP tends to be higher on cold days than on hot days.

Similar results have been reported from other countries like the US, Australia, the UK, Finland, and Singapore.

REFERENCES:

1. Shan A, Chen X, Yang X, Yao B, Liang F, Yang Z, Liu F, Chen S, Yan X, Huang J, Bo S, Tang NJ, Gu D, Yan H (2021) Association between long-term exposure to fine particulate matter and diabetic retinopathy among diabetic patients: a national cross-sectional study in China. Environ Int 154:106568.

2. Yang X, Yang Z, Liu Y, Chen X, Yao B, Liang F, Shan A, Liu F, Chen S, Yan X, Huang J, Bo S, Liu Y, Tang N, Gu D, Yan H (2021) The association between long-term exposure to ambient fine particulate matter and glaucoma: a nation-wide epidemiological study among Chinese adults. Int J Hyg Environ Health 238:113858.

3. Zhang A, Wang Q, Yang X, Liu Y, He J, Shan A, Sun N, Liu Q, Yao B, Liang F, Yang Z, Yan X, Bo S, Liu Y, Mao H, Chen X, Tang NJ, Yan H. Impacts of heatwaves and cold spells on glaucoma in rural China: a national cross-sectional study. Environ Sci Pollut Res Int. 2023;30:47248-47261.