Look away if you're squeamish.
In a stomach-churning video footage which has gone viral this week, a doctor in India is shown performing the unfathomable - pulling a 15cm-long worm from a patient's eye.
The doctor, identified as Dr Srikanth Shetty, says that the 60-year-old man from Karnataka state in Southwest India had come to him complaining of pain and itchiness in his eyes.
And the cause is believed to be a parasitic roundworm known as Wuchereria Bancrofti, nestled comfortably in the sclera (white part of the eye).
A similar medical nightmare was last reported in 2012, when a 75-year-old Indian man had a 13-cm worm pulled out of his eye after complaining of persistent eye pain and twitching. It was not determined what type of worm it was.
Doctors at JJ Hospital, one of the Mumbai’s largest medical facilities, said at the time that they had encountered only one such instance in the past 20 years, but the insect was only 2 to 3 cm long.
Parasitic roundworms are most commonly transmitted through mosquito bites, say experts, when a mosquito's eggs are released and deposited into the bloodstream. In this patient's case, the eggs could have hatched in the eye.
If left untreated, it can infect the lymphatic system and may lead to a condition known as elephantiasis, marked by swelling in the limbs, breasts or genitals.