A 21-year-old British man who thought his blurry vision was a sign he required glasses was later diagnosed with a golf ball-sized brain tumor.

Harry Mockett, a musician, told South West News Service (SWNS) he first noticed his deteriorating vision when he struggled to read the questions while watching the popular game show “Who Wants to Be a Millionaire?”

Mockett went to see an optician who gave him glasses. But after a week of wearing them, the 21-year-old saw no improvement — literally. His vision remained blurry.

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At a follow-up appointment, the optician spotted a mass behind his eye and urged Mockett to seek medical attention.

Tests revealed a tumor was pressing on his optic nerve, causing blurry vision. Mockett told SWNS that, other than issues with his eyesight, he had no other symptoms of a brain tumor, which often include headaches, nausea or vomiting, drowsiness, and sleep and memory problems.

“I had no other symptoms other than my vision seeming to get blurrier, and I thought I just needed glasses — I had no idea I had a brain tumor,” he said.

"I had loads of assessments done at the hospital over the next week, and they booked me in for an MRI scan, but I didn't think too much of it. I really thought I was absolutely fine, I felt perfectly healthy — I even went out to a gig with my mates two days before the MRI scan,” he continued.

But Mockett was soon informed of the brain tumor — a craniopharyngioma — and was told he required immediate surgery to remove it.

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"My [mom] obviously burst into tears, but I tried my best to remain calm and just focus on what we needed to do next,” he recalled.

Following a 6-hour surgery, about 98 percent of the tumor in Mockett’s brain was removed. But his battle wasn’t over yet, as he suffered life-threatening complications following the surgery, such as fluid on the brain. He also reportedly contracted bacterial meningitis, according to SWNS.

Doctors told his family Mockett had just a 50 percent chance of surviving the night following his surgery. But Mockett pulled through, later undergoing proton therapy to shrink the tumor, which was benign.

"Being in the hospital for six months was really isolating. I've always been healthy and had no experience of staying in hospitals at all,” he told SWNS. "The tumor and the surgery really played with my memory, and sometimes I'd make no sense at all.”

"I have always loved playing the guitar and was worried that the damage might affect my ability, but miraculously it didn't alter how I played at all,” Mockett added, noting the instrument was his “biggest companion” while he recovered.

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“Writing songs gave me a purpose and kept me focused on my future,” he said.

By February 2019, Mockett was given a clear bill of health.

"It all happened so fast — one day I was chilling at home, the next they were rushing me into surgery to save my life,” he said. “It feels good to take back control of my life after this hellish year, and I'm looking forward to a more positive future after battling and beating a brain tumor.”