During CNN”s town hall on Wednesday evening, Joe Biden’s left eye turned red while he answered questions about climate change. The 76-year-old Democratic presidential frontrunner didn’t seem to notice, but viewers did and his bloodied eye overshadowed his efforts to advance the Left’s climate change agenda.

A subconjuctival hemorrhage may be caused by many things including excessive straining such as coughing, sneezing, or vomiting, trauma to the head or eye area, an eye infection, a bleeding disorder, and blood thinner medication. It can also be a symptom of high blood pressure, diabetes, leukemia, and sickle cell disease.

Around the same time, Biden’s campaign tweeted, “We can’t turn a blind eye to the way in which environmental burdens are distributed unevenly along racial and socioeconomic lines.”

Biden’s health has been questioned since he has appeared to have memory issues and slurred speech during his campaign. In 1988, Biden had two life-threatening brain aneurysms.