A businesswoman who thought she was suffering from hayfever was shocked to discover her stinging eyes were due to a - brain tumour.
Gurcharan Kaur, 30, suffered irritated eyes for weeks but shrugged it off as an allergy caused by pollen or dust and dosed up on antihistamines.
Sightseeing in London last month, Gurcharan noticed her eye was becoming more irritable than normal and it was becoming painful to blink.
The Etsy business walked past an opticians and decided it was time to get some help.
Despite initially being told to use eye drops, she returned and a test revealed she had optical nerve damage on her left eye.
Doctors discovered she had a small colloid cyst - a slow-growing tumour in the centre of her brain, behind her left eye.
She was weeks away from developing seizures, they said, and she had brain surgery to remove the benign mass.
Now tumour-free, Gurcharan, from Wolverhampton, wants to warn others of downplaying possible life-threatening symptoms.
She said: "I just thought I was developing hayfever.
"My eye would just sting in the morning but I'd just take an antihistamine and it would go away.
"I knew you could develop it at any time and I just thought it was just a case of that.
"I'd also been feeling dizzy and tired for a couple of months but I just shrugged it off.
"I've always had perfect vision so it didn't even cross my mind it would be something this serious.
"I feel like walking past Vision Express was a sign.
"If it hadn't been there I would have just ignored it and avoided getting it checked out."
Gurcharan was on her way to meet older sister Sharan, 36, last month when she was spurred into action.
She walked past a Vision Express store and decided to pop in, but she couldn't get an instant appointment, and experts advised her to get eye wash, she said.
Gurcharan said: "My eye was itching and I just thought it was a sign.
"My sister was still at her job interview so I had a bit of time by myself.
"I only went in there on a whim.
"I didn't actually think I had something wrong with me.
"It was just a coincidence that I walked past it."
A few hours later Gurcharan returned to the Oxford Street store after noticing her left eye was beginning to turn red.
Staff did an standard eye test and discovered Gurcharan - who hadn't had an eye appointment in ten years - had optical nerve damage on her left eye.
She said: "I just kept complaining about how much it hurt.
"I kept getting my mirror out of my bag to check if there was anything in my eye.
"My eye was just really, really itchy.
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"I only went back as my sister was getting bored of me banging on about it.
"By this time my eye started to get a bit red and it started to hurt when I blinked.
"The last time I went to the opticians I was told I had 20:20 vision so it just didn't seem right.
"I went up to the desk and the employee went to get a second opinion.
"A different member of staff saw me this time and said they could squeeze me in."
She was referred for a CT scan, and the pair took the train home and went straight to New Cross Hospital, in Wolverhampton.
Doctors discovered abnormal fluid on her brain, and a further scan revealed a small colloid cyst - a slow-growing tumour typically found near the centre of the brain.
It was behind her left eye and warned she was weeks away from developing seizures, she said.
Days later she had a two-hour operation which saw doctors cut her head open through minimal invasive surgery to remove the mass, sending Gurcharan home with a two-month course of epilepsy tablets.
Gurcharan said: "Thankfully it wasn't any bigger.
"I've been scared for my life.
"I just want to warn people about ignoring what can be quite serious symptoms.
"I just kept shrugging off "I would feel sick but after I took a hayfever tablet it would stop.
"But walking past that Vision Express shop was almost like a sign.
"I had been burying my head in the sand but "I just knew something wasn't quite right so that's why I went back.
"The doctors told me if I hadn't gone in it would have grown and I would have had started having seizures."