Dozens of people with serious eye problems due to oak processionary caterpillars

Dozens of people with serious eye problems due to oak processionary caterpillars

NOS reports that dozens of people in the Netherlands are suffering from serious eye problems due to the stinging hairs of the oak processionary caterpillar. At least 10 people have been affected so severely that they will have long-term and possibly permanent symptoms.

Serious health issues

In many places in the Netherlands, the number of oak processionary caterpillars has tripled compared to last year. The stinging hairs the caterpillar sheds whilst crawling over the bark of oak trees can cause serious health issues for both humans and animals, such as severe allergic reactions, skin rashes, breathing problems and eye injuries.

Incorrect diagnosis

Dutch ophthalmologists have stated to NOS that they have seen at least 92 cases where patients have come in with severe eye problems due to the stinging hairs of the caterpillar. In most cases, the patients had eye problems for weeks. Generally, people go to their GP first with eye complaints (burning sensation, red or infected eye).

However, ophthalmologist Tjeerd de Faber states that many GPs don’t have the necessary equipment to determine the real cause behind the complaint; the minuscule and sharp hairs of the caterpillar. To spot a hair from an oak processionary caterpillar you need a microscopic lamp.


As long as the hair is on the surface of the eye, you can try rinsing it out with lukewarm water. However, if the hair penetrates the eye and gets behind the cornea, minor damage can occur which can worsen your eyesight. The eye can also become inflamed because the body wants to get rid of the hair and responds accordingly.


De Faber says that while treatment can take a long time, usually the eye recovers properly. He is not aware of any case where a patient has experienced a total loss of vision.

Pine processionary caterpillar

Pine processionary caterpillar-expert Silvia Hellingman tells NOS that the pine processionary caterpillar might be on its way to the Netherlands as well: “It is not here yet, but you can find the caterpillar in Belgium and Luxembourg. It is only a matter of time before it makes its way here.”

The pine processionary caterpillar is a lot more dangerous than the oak processionary caterpillar, as it has many more stinging hairs.

Manja van Kesteren


Manja van Kesteren

Manja studied English and Creative & Professional Writing at the University of Wolverhampton in the UK. She is passionate about books, arts and crafts, Netflix, metal music, cheese, and her...

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