Ocular allergy affects millions of people worldwide. It is generally intermittent but sufferers’ quality of life is affected by the resulting ocular discomfort and inflammation: in severe cases they may experience vision disturbance and find that daily activities are hindered.
Common causes of ocular allergy include mites, animal allergens and moulds, which are found indoors; grass, tree and weed pollens, and mould spores, found outdoors; food allergens such as fruits, vegetables, nuts, milk, eggs, shellfish or fish; and injected allergens including insect venoms and therapeutic proteins.
Changes to our environment from the combined effects of warming and more CO2 mean that the allergy season is becoming longer from year to year, with pollen seasons starting earlier, lengthier peak-pollen periods and even some pollen presence in the winter.
Rising temperatures are changing the botanical landscape, increasing the geographic distribution of allergenic plants, and the amount of pollen in the air will continue to increase as climate change worsens.
As an example of the direct link the environment can have with our health, the number and severity of ocular allergies was observed to increase dramatically in spring 2012 when air pressure, temperature, pollen count and PM10 levels were unusually high. These phenomena seem to increase every year: 2017 was the second-hottest year on record according to NASA data, and was the hottest year that did not have the short-term warming influence of an El Niño event.1