An eye-opening tale about the hazards of keeping pet tarantulas


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Here’s a medical mystery – and a cautionary tale – for all you tarantula owners out there, courtesy of the new issue of the Lancet:

A 29-year-old British man with a red, watery and photophobic eye sought treatment from his general practitioner. The doctor presumed the patient had conjunctivitis (also known as “pink eye”) and prescribed an antibiotic ointment.


However, his symptoms persisted three weeks later, so he went to an ophthalmology practice at St. James’s University Hospital in Leeds. The specialists initially considered a very similar diagnosis of viral keratoconjunctivitis, which involves inflammation of the cornea as well as the conjunctiva.

Then they examined the patient’s eye under higher magnification and found “fine hair-like projections” at “varying depths within the cornea.”


The ophthalmologists weren’t sure what to make of them, so they asked the patient. He instantly recalled an incident from three weeks earlier, when he was cleaning the glass tank (or terrarium) that housed his pet Chilean Rose tarantula.

Here’s what went down, as described in the Lancet:

While his attention was focused on a stubborn stain, he sensed movement in the terrarium. He turned his head and found that the tarantula, which was in close proximity, had released a “mist of hairs” which hit his eyes and face.

It turns out that many tarantula breeds, including this one, are known to shoot fine barbed hairs at their attackers as a self-defense mechanism. Mystery solved! The patient was diagnosed with ophthalmia nodosa, a condition in which the eye reacts to “insect or vegetable material,” the ophthalmologists reported.

The doctors tried to remove the hairs from the patient’s cornea but even their micro-forceps were too big. So they prescribed steroid drops, which he still takes once a day. The patient’s visual acuity has improved and he says he has only mild discomfort and intermittent floaters.

It was a rare diagnosis, but not unprecedented. The doctors were able to find three prior case reports of opthalmia nodosa caused by tarantula hairs in the medical literature going back to 1988.

At the end of the ordeal, the treating physicians offered this helpful guidance to their patient and others who may find themselves similarly situated:

We suggest that tarantula keepers be advised to routinely wear eye protection when handling these animals.

Sensible advice indeed, which the patient is reported to have taken to heart. But in my (admittedly non-medical) opinion, perhaps a better suggestion would have been to give up the pet tarantula altogether.

-- Karen Kaplan