The tarantula that did the damage
The owner of a tarantula spider has suffered severe eye inflammation from cleaning out his pet's cage, doctors have reported.
They say the man had no idea his pet was the problem when he came to their clinic for treatment.
When they told him they could see tiny hairs sticking out of his eyeball he remembered his pet spider sending out a mist of hairs which hit his face.
The doctors say anyone working with spiders should wear eye protection.
Dr Zia Carrim, of St James's University Hospital in Leeds, writing in the Lancet, says the man came to his clinic in February, having had a red, watery and light sensitive eye for three weeks.
It was when he was examined under a high magnification lens, that hair-like projections were spotted at various depths within the cornea.
When these findings were described to the patient, he immediately recalled an incident that had preceded the onset of his symptoms.
Three weeks earlier, he had been cleaning the glass tank (terrarium) of his pet, a Chilean Rose tarantula.
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.
New World tarantulas from North and South America have urticating hairs as their first line of defense
All have a venomous bite but it is not deadly to humans
Because other proteins are injected into the victim along with the venom some humans may experience a severe allergic reaction to their bites
Dr Carrim said: "It was very obvious that the course of the inflammation was driven by these tiny hairs.
"We attempted removal of corneal hairs for our patient under the operating microscope but even with the smallest pair of forceps it was impossible. "
The Chilean Rose tarantula ( Grammostala rosea) is one of the most commonly imported tarantulas.
It is believed to be hardy and docile, but it is venomous and has urticating hairs, which can cause a stinging pain, over the back end of its abdomen.
As a defence mechanism, the tarantula will rub its hind legs against its abdomen to dislodge these hairs into the air.
The authors said the spider was about 15 to 20 cm from his eye.
The hairs have multiple barbs that allow them to migrate through the eye tissue to various depths.
Patient's inflamed eye
Their patient had both surface irritation and evidence that some had migrated through to the innermost endothelial layer of the eyeball provoking inflammation in the interior of the eye.
"He was treated with steroids to dampen down the response" Dr Carrim said.
"And he will remain on long-term treatment with steroids at a very low dose."
Keepers at Whipsnade Zoo estimate that thousands of people in the UK are keeping tarantulas as pets.
David Field, director of the Zoological Society of London, said: "I advise anybody keeping such tarantulas as pets to be aware of the danger."