Joe Biden’s eye appeared to be bleeding during a CNN town hall on climate change. Eagle-eyed viewers took to Twitter to express concern about the bloody eye.

While others questioned whether photos on Twitter of Biden’s bloody eye were photoshopped, here’s video that shows that Joe Biden’s eye does appear to be bleeding or bloody during the CNN town hall. Washington Examiner reported that Biden’s eye appeared to have a burst blood vessel during the CNN town hall on September 4, 2019. You can watch the video and judge for yourself.

People took to Twitter to comment. “@JoeBiden What happened to your eye?” wrote one Twitter user. “Can’t turn a blind eye but Joe sure can turn a bloody one,” wrote another. Another wrote: “remember when lebron james in his final season with the cavs played the entirety of the finals with a broken finger and a bloody eye? this is how i’m choosing to view the joe biden campaign in this moment.”

VideoVideo related to watch: joe biden’s bleeding eye during cnn town hall 2019-09-04T21:37:33-04:00

After the town hall, Biden tweeted, “We can’t turn a blind eye to the way in which environmental burdens are distributed unevenly along racial and socioeconomic lines. Biden will right these wrongs and stand up to fossil fuel companies who disproportionately harm communities of color and low-income communities.”

It’s no secret that Joe Biden has blood in his eye for President Trump, but when you’re 76 years old it does nothing positive for your image or for age-focused Americans.

This took place during Wednesday's CNN town hall event. pic.twitter.com/MLvg6hBoRn — Jerry Davich (@jdavich) September 5, 2019

These are the candidates who will appear on stage at the September 12, 2019 Democratic presidential debate: Former Vice President Joe Biden; Sens. Cory Booker of New Jersey, Kamala Harris of California, Amy Klobuchar of Minnesota, Bernie Sanders of Vermont and Elizabeth Warren; South Bend, Ind., Mayor Pete Buttigieg; former Obama Housing Secretary Julián Castro; former Rep. Beto O’Rourke of Texas and entrepreneur Andrew Yang.

What time is the 2020 Democratic presidential debate on? It will air from 8-11 p.m. ET on ABC and Univision. It’s the third presidential debate, and all eyes will be on Joe Biden as challengers try to knock him off his perceived frontrunner’s perch. According to NPR, to get into this debate, candidates needed to demonstrate that they had “2% in at least four Democratic polls, either nationally or in early states, as well as 130,000 donors from at least 20 states and at least 400 in each state.”

The debate is being held at Texas Southern University.

Here’s what you need to know:

The Bleeding Eye May Raise Concerns About Joe Biden’s Health But Bloody Eyes Can Be Caused by Mundane Reasons

Joe Biden’s age could become an issue on the campaign trail. The former vice president is 76-years-old. He was born on November 20, 1942. However, President Donald Trump is no spring chicken, either. Donald Trump is 73-years-old. Rounding out the geriatric presidential contenders, one must not forget Bernie Sanders. He’s older than Biden actually; he’s 77. Elizabeth Warren is 70.

What can cause a bleeding or bloody eye? Of course, one shouldn’t try to diagnose a person, including Biden, over the Internet. However, WebMD does report that a broken blood vessel in the eye is sometimes called a “Subconjunctival Hemorrhage.”

Uh, hey guys. Joe Biden’s eye filled with blood while onstage at the CNN town hall.

This is not a photoshop: pic.twitter.com/kJRHxMP8wc — Benny (@bennyjohnson) September 5, 2019

According to WebMD, “Most subconjunctival hemorrhages are spontaneous without an obvious cause. Often, a person may discover a subconjunctival hemorrhage on awakening and looking in the mirror.” In fact, there are some mundane causes for such bleedings. WebMD reports that these can include sneezing, coughing, straining, eye rubbing, trauma from injury, high blood pressure or a bleeding disorder. The site recommends people see a doctor when the bloody eye persists, when it’s accompanied by other symptoms like bleeding gums, and when it’s accompanied by vision changes, among other things.

A journal article called Subconjunctival hemorrhage: risk factors and potential indicators on such hemorrhages explains, “Subconjunctival hemorrhage is a benign disorder that is a common cause of acute ocular redness. The major risk factors include trauma and contact lens usage in younger patients, whereas among the elderly, systemic vascular diseases such as hypertension, diabetes, and arteriosclerosis are more common.” The article was published in the Journal of Clinical Ophthalmology.

It’s not clear what caused Joe Biden’s eye to bleed.

That’s not the only possible cause though. The American Academy of Ophthalmology lists a number of other ailments that bloody eyes can be associated with, ranging from glaucoma to corneal ulcer. You can see the list here.

Joe Biden's left eye fills with blood during CNN town hall on 'climate crisis' via @washtimes https://t.co/m50cibpZ9V pic.twitter.com/Nw16uwPCQ4 — ?.??????? (@cticasso) September 5, 2019

Joe Biden has had some health issues over the years. According to Delaware Online, Biden suffered “two life-threatening brain aneurysms” in 1988. He only had a 50 percent chance of surviving one of those surgeries, the newspaper reported, quoting him as saying of that surgery, “In fact, I felt becalmed, like I was floating gently in the wide-open sea. It surprised me, but I had no real fear of dying. I’d long since accepted the fact that life’s guarantees don’t include a fair shake.”

A Biden Presidency Would Set Age Records

Biden’s age means that he would be 78-years-old on inauguration day if he were to win the presidency in November 2020. He would be 82 if he sought re-election.

According to Forbes, Biden would be significantly above the average age for a president, which is just over 55.

If Joe Biden is elected president, he will take Trump’s place as the oldest president ever elected. If Biden wins the Democratic nomination, he might be teamed with a younger vice president to neutralize the age issue, according to Bloomberg.

Here are the oldest presidents at the time of their inauguration, along with their ages at the time they took office:

1. President Donald Trump: Age 70

2. Ronald Reagan: Age 69

3. William H. Harrison: Age 68

4. James Buchanan: Age 65

5. George H.W. Bush: Age 64

Who were the youngest presidents at the time of their inauguration? They were:

1. Theodore Roosevelt: Age 42

2. John F. Kennedy: Age 43

3. Bill Clinton: Age 46 years, 5 months

4. Ulysses S. Grant: Age 46 years, 10 months

5. Barack Obama: Age 47 years, 5 months

Of course, you can look at the age question two ways: Who was the oldest president at the time of taking office, and who was the oldest living president – ever – former or current.

George H.W. Bush, when he died on November 30, 2018, was 94-years-old. That put him into the record books when it comes to the oldest president in U.S. history, but it was for long.

Bush held two distinctions at the time he died; he was the United States’ oldest living president, but he was also the oldest president in the history of the United States. He officially set the record as the nation’s oldest living president ever when he reached 93 years and 166 days.

However, George H.W. Bush did not hold that record for long. That’s because Jimmy Carter, who is still alive, is also 94-years-old. Carter was born a couple months after Bush. On March 22, 2019, he also became the nation’s longest living president – ever.

READ NEXT: Joe Biden’s Age Vs. Bernie Sanders’ Age.