An “eye” on allergies… understanding why your eyes itch during spring.

Nov. 2, 2021

The keen observer may have recently seen a question in the Melbourne Pollen App hay fever survey about your eyes.

As a user of the App, you probably already know that most people who suffer from hay fever also experience itchy, red and watery eyes when their symptoms are high. This is because the same chemicals released by your immune system that cause hay fever symptoms, also cause similar problems in your eyes. Specifically, the part of your eye that is most affected is called the conjunctiva.

We’re looking for people to help us get a better understanding of what actually happens to the surface of the eye (the cornea) on a microscopic scale and you can help by registering your interest in participating in this research study here:

Why your eyes get red and sore in spring.

Did you know that the conjunctiva and the cornea (clear dome at the front of your eye) have their own special immune system? There are few different groups of white blood cells that live in this part of the eye, and they cruise around like security guards, checking for suspicious foreign agents, like germs, or, even seemingly innocent particles like pollen!

For some people, these security guards (called immune cells) are not very good at knowing the difference between harmful threats, and safer things like pollen, or dust. So, in some people with hay fever, the immune cells sometimes sense the wrong message, over-respond a bit and release lots of chemicals that cause itchiness, watery and red eyes. These symptoms tend to be worse during high pollen days, most commonly during Spring and Summer, and are often a sign that a person has a condition called seasonal allergic conjunctivitis.

If you think you might be suffering from eye allergies it may be worthwhile to make an appointment to see your optometrist. Optometrists are highly trained health professionals who can diagnose eye allergies, and can also advise on what types of therapies would be best to help control your symptoms.

Participate in our research study so we can better understand why your eyes get red and sore.

A/Prof. Laura Downie, Dr Holly Chinnery and their team from the Department of Optometry and Vision Sciences at the University of Melbourne are studying the biology of the immune cells that live on the surface of the eye and how they change when the pollen count is high and when it’s not.

Our research study will compare both adults who experience eye allergy symptoms in Spring, and those who do not have eye allergies. Participants will attend two study visits at the University of Melbourne, spaced about six months apart (i.e., November/December 2021 and April/May 2022).

Selected participants will be given a comprehensive general eye exam and they will also be assessed for dry eyes and eye allergies. The team will then use a specialised microscope camera to collect high-resolution photographs of the immune cells on the surface of the eye. To give you an idea about how small these cells are, they are typically about 8 times smaller than the thickness of a human hair. The images are so detailed that the shapes, sizes, location and even the movement of these immune cells in the cornea can be measured and compared in people who have eye allergies relative to those who do not experience eye allergies. We’re estimating the entire study will take about 3 hours to complete, but it will give you a good idea of the health of your eyes and it will really help us get a better understanding of why some people get very sore eyes in peak pollen periods.

If you would like to participate in our research, you can register your interest in participating here:

eye confocal

Image: Left: A/Prof Downie viewing the front surface of the eye at high magnification using a slit lamp biomicroscope. Right: a high-resolution confocal image showing the nerves and immune cells in a human cornea.

This article was prepared by Dr Holly Chinnery and A/Prof Laura Downie from the Department of Optometry and Vision Sciences, The University of Melbourne. This research project has been approved by the Human Research Ethics Committee of The University of Melbourne (HREC 22828).

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