A 29-year-old doctor from Bristol saved her vision after a "game-changing" test, discovering a mysterious infection that plagued her health for five years.

Ellie Irwin's right eye has continued to inflamed, causing blurred vision, to no avail. At some point, she even thought her eyes were removed.

Only after Ellie was given an analysis called metagenomics, she was diagnosed with a rare bacterial infection and cured with antibiotics.

“It’s transformative,” Ellie told the BBC. “I feel very lucky.”

Professor Carlos Pavesio, consultant ophthalmologist at Moorfields Eye Hospital in London, said Ellie’s case was a “breakthrough in diagnosing the infectious disease”.

"Over the years, we have many patients with chronic infections, but despite multiple tests, we cannot identify responsible mistakes."

In 2019, Ellie was still in medical school and her right eye began to suffer from inflammation. All infections tested negative and she was considered to have an autoimmune condition.

Ellie prescribed steroid eye drops and immunosuppressants, some of which need to be given by intravenous infusion.

"It totally takes up my life," Ellie said. "I need every hour of my eyes to fall and it's hard to balance the start of that junior doctor. My vision is really variable, and I'll have some bad days."

“I’m taking a lot of medication and going on a lot of dates, but I don’t feel like I’m getting better.”

Treatment and inflammation lead to Ellie having to surgically remove a cataract after graduating from medical school.

Ellie said she finally reached the "breaking point" and even began to consider being affected to take away her eyes.

“While it’s scary to lose sight of one eye, my biggest fear is that it may be scattered on my left eye,” she said.

It is one of Dr. Ellie at Bristol's Nanmead Hospital, who recommends using metagenomics, the last resort test that patients are usually not available to, only if the standard diagnostic tools fail to identify or exclude infections.

Metagenomic technology uses cutting-edge genome sequencing to identify all bacteria, Funghi, or parasites present in the sample by comparing them to a database of millions of pathogens.

A team at Moorfields Ophthalmology Hospital arranged a sample of liquid taken from inside Ellie's eyes and sent to Metagenomics Labs at Great Ormond Street Hospital (GOSH), the only lab officially recognized in the UK to perform these diagnostic tests on patients, and the only few diagnostic tests in the world.

Currently, the standard method for detecting bacterial infection is to try to plant samples in a petri dish.

For viruses, the most common diagnostic tool is PCR testing. Many of these pandemics will be familiar with this, when millions of swabs were circulated in posts to confirm if they were involved.

However, Dr. Julianne Brown, chief clinical scientist at GOSH Megenomics Service, said PCR has some drawbacks.

"The trouble with PCR is that you have to consider the virus that may cause the infection and do a separate test for each," she said. "So if you get something unexpected, rare, or didn't know before, you won't find it."

Metagenomics is “a huge advancement – ​​it’s a complete game changer”, Dr. Brown said.

In Ellie's case, metagenomics diagnosed rare strains of bacterial infection found in South America.

Now, it is speculated that Ellie swam on the Amazon River in 2018, traveling to Ecuador and Colombia.

Ellie said it was an emotional moment when she got the test results.

"I'm broken - I just have to cry. I never thought it would restore the front and become something to heal," she said.

"Give me three weeks of antibiotics, and within a few days my vision became clearer and the inflammation subsided."

The price of a single metagenomic test is around £1,300, far exceeding the standard diagnosis. However, as technology develops, prices may fall rapidly.

Virologist Professor Judy Breuer, who has been developing metagenomics at London GOSH and the University of London (UCL) for more than a decade, said her team currently receives three to four samples per week from hospitals across the UK, in addition to performing metagenomic testing of their own patients.

These are usually samples of parts of the human body that are usually sterile sites, and no bacteria are found, such as the brain, central nervous system, liver and eyes.

"In the future, we think metagenomics will be the frontline test and be able to diagnose infections in any sample, which may be within the same day," she said.

It may also become faster, cheaper, and easier to do, which means it will be used for more patients, not just a serious discomfort minority.

Solving her eye problems allows Ellie to focus on her training as a GP and arrange weddings.

Ellie married in Newcastle on March 29, the same day the city celebrated Newcastle United's victory in the Calabar Cup.

"We were yelling from Ants and Dec and rising up on the scissors above Newcastle United fans, which was incredible," she said.

Professor Breuer said she was excited about the changes in treatment.

“It’s amazing to see the impact it has on patients like Ellie.”