All About Eye Allergies
Pollen can set off weeping, blurred vision, itching and rubbing. How do you find relief?
When Ken Hegan traveled to Vancouver a couple of years ago, the city was experiencing one of its warmest Februaries on record, and the trees began showering unwitting visitors with an early blast of pollen. “It felt like my eyes were being assaulted by pollen,” says Hegan.
The filmmaker and humor writer recalls his eyes were red and teary, and this year he’s bracing for the same back home in Toronto.
“Sometimes I wake up and my eyes are caked shut. And when I walk my dog in the morning, I look like I’m crying. My neighbors just think I’m some sad sack guy who cries all the time,” Hegan says with a laugh.
Like millions of fellow allergy sufferers, Hegan’s eyes itch, burn, swell and redden every pollen season, and his vision blurs because of the non-stop tearing. (Others can get such eye symptoms from allergy triggers such as pet dander, mold and dust mites.)
As an avid cyclist, Hegan even fears red lights because when he stops moving, his baby blues well up – and the itch kicks in. “I’m always knuckling away at my eyes. I know I’m not supposed to, but my mom’s not there to tell me to stop,” he jokes.
Despite their mothers’ admonitions to quit that knuckling, people with allergic conjunctivitis – the inflammation of the membrane that covers the white of the eye and the inner eyelid – find that easier said than done.
Pollens’ Chemical Cascade in the Eye
The fact is, they are faced with an annoying and uncomfortable reaction that occurs when pollens or other allergens enter the eye and trigger the same allergic chemical cascade that can occur in the lungs, the nose or on the skin.
Canadian allergist Dr. Harold Kim has a strong interest in eye allergy symptoms. He explains that allergic patients’ eyes contain cells – mostly mast cells – that are primed for allergen exposure. When confronted with the allergen, antibodies called IgE will cause the mast cells to rupture and release chemicals including histamine, one of the main culprits behind the inflammatory response in the eye and surrounding tissues.
For most patients, the resulting symptoms are an annoyance. But the results can be much more serious, especially for those who experience swelling of the conjunctiva itself.
“It looks almost like jelly,” says Kim, who himself suffers from mild eye symptoms during allergy season. “It’s not vision-impairing, but it’s very irritating.”
However, in the most severe cases, the cornea itself can be affected if people don’t resist the temptation to rub and scratch.
“The mechanism is not completely known, but it may be partly from inflammation and partly from scratching, and that can be vision-impairing,” Kim warns. “So those patients should see an opthalmologist and be treated relatively aggressively.”
Next: Eye Allergies: Contact Lenses and the Role of the Nose