Zac Morey, who is in Year 5 at school, lost vision in his left eye less than a week after testing positive for Covid-19.His eye completely closed up during the terrifying ordeal after he was diagnosed with orbital cellulitis - a skin infection that some scientists have linked to Covid-19.
Zac, from Bristol, has since fully recovered but his family have issued a warning.
Mum Angela, 37, said: "His eye looked like it was going to explode. There was no way he could open it without pulling the skin. It was swollen beyond anything I've ever seen."
Zac's eye problem started after he positive for Covid along with his mum and four siblings on December 16.
The youngster suffered cold-like symptoms and spent his self-isolation period playing computer games at home.
But on December 22 - when he twice tested negative for Covid - he developed pain in his left eye.
Angela, a local councillor, said: "I thought it just been on the computer for seven days solid so didn't think anything of it. But by Christmas Eve it was not good at all. We took him to hospital and he was put on an antibiotic drip until Boxing Day.
"They said if it goes too far into the eye then it can cause blindness. The doctors said it was an allergic reaction to the virus that affects children."
Zac was discharged from hospital on Boxing Day after undergoing an eye test that confirmed his vision had fully recovered.
The World Health Organisation lists red and irritated eyes as an uncommon side effect of Covid-19, while various studies have linked orbital cellulitis and coronavirus.