A man who had blurred vision, redness, pain and floaters in his eye had a “fairly long” worm trapped inside.
In New Delhi, India, a 25-year-old man went to the doctor after experiencing poor vision and painful symptoms in his left eye for two weeks, according to the case report published in the medical journal BMJ Case Reports on Jan. 8.
Medics noted that he had 20/20 vision in his right eye, but 20/160 in the left, a considerable degree of visual impairment.
Upon examination, a parasitic worm was discovered inside the vitreous cavity of his eye. Doctors believe the parasite migrated to the man’s eye while in the larval stage, either by burrowing through the layers of the eyeball or by traveling through blood in ciliary vessels.
(Man's eyeball, with parasitic worm circled. Photo Credit: BMJ Case Reports 2016 via Daily Mail)
Surgeons decided to remove the worm, as anti-parasitic drugs may have negatively affected the man's inflamed eyes. Two weeks after surgery and a follow-up treatment, the man's vision had improved to 20/40.
The specific parasite is a Loa loa roundworm, which is endemic to Western and Central Africa. Male parasites grow to 1.35 inches and females grow to 2.75 inches. Doctors reported this was the first case of Loiasis, an infestation of the Loa loa worm, in the vitreous cavity of the eye that has ever been reported.
As the patient is a fruit vendor, and doctors think flies carrying the parasitic worm may have been attracted to his produce.
Roundworms or nematodes found in the eye tend are usually transmitted through insects, the Daily Mail reports. Professor Mark Viney, a biologist from the University of Bristol, explained that worm larvae can be transferred when people are bitten.
“They grow into adults which make their own young, and some of those young can travel through tissues and end up in the eye," Viney told the Daily Mail. “It can live in the eye because as a parasite it has evolved to live inside other animals. The worm has evolved to change the host’s immune response to further its own survival."
Because of the way in which these worms interact with the immune system of their hosts, researchers are investigating how this mechanism could be used for immunotherapeutic reasons.
“People with irritable bowel syndrome could be given worms to change their immune response so they don’t have symptoms,” Viney explained.