What caused the eye injuries at the recent Trump rally? We asked an expert

• Several people who were on stage with Donald Trump at his rally in Tucson, Arizona, reported eye injuries after the event, saying they experienced pain and temporary blindness.
• Although he said he would have to really examine the patients to be sure, Dr. Jules Winokur, residency program director and vice chair of ophthalmology at Northwell Health, told PEOPLE that their injuries could have been caused by accidental chemical exposure or UV light toxicity.
• He said both could explain the painful but temporary symptoms.

Several attendees who recently shared the stage with Donald Trump at a rally in Tucson, Arizona, reported significant eye injuries following the events of September 12. They said they felt burning pain and temporary blindness immediately afterward.

Some visitors sitting to the left of the stage subsequently sought medical attention, NBC affiliate KVOA-TV reported.

“When I try to open my eyes, I can't see anything. I see a bright light. It hurts, it hurts a lot to open my eyes. I have this cold cloth that I keep putting on and taking off. It's horrible,” Mayra Rodriguez told the outlet.

Other reported symptoms included flushed faces and runny noses – but everyone had the same painful eye symptoms.

What could have caused this temporary – but painful – condition?

Dr. Jules Winokur, residency program director and vice chair of ophthalmology at Northwell Health, tells PEOPLE that the symptoms indicate either accidental chemical exposure or UV light poisoning.

“There is no way I can know what is going on based on the reports,” Winokur warned, adding, “We have to investigate people to find out what is going on.”

Since the symptoms were painful but temporary, he suspected that “perhaps a chemical was involved, as it can irritate the eye.”

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“Alcohol-based products are often used in cleaning, and alcohol is toxic to the eyes. Heavy cleaning agents may have been used in this area. [that] then transferred it to their hands, and they rubbed their eyes and imagined something.”

“It's really hard to say, but it could have been some kind of chemical exposure,” Winokur told PEOPLE. And chemical exposure, he said, “goes away, it gets better and people heal.”

“The other possibility is something called UV toxicity,” he explains, a condition that occurs when too much UV radiation causes inflammation of the surface of the eye – a potential danger if UV light was used at the venue.

Colloquially, it's called “snow blindness,” explains Winokur. “The sunlight reflects off the snow and if you don't wear UV protection, you're exposed to UV overdose. And that actually causes significant pain and discomfort.”

He compared it to the pain that welders can feel when they do not wear a UV-protective mask.

“When they weld without a welding machine, they often experience severe pain and vision problems. [and their] Eyes watering.”

Regarding the suggestion that there might have been chemical contamination from the ventilation shafts, Winokur said the small, concentrated group of participants did not support this theory.

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“These were concentrated in a certain area – it wasn't like everyone in the arena had something,” he said. “It just doesn't make sense that a vent was toxic and just happened to spray air on those people.”

Winokur explained, “The air treatment is so extensive and large,” in places like the Linda Ronstadt Music Hall, which has a capacity of more than 2,000 people.

A third possibility would have been for someone to aim a laser pointer at the participants, which “could actually burn the inside of the eye,” he said. But he added, “that would cause permanent vision loss” – and participants reported that their symptoms improved.

“The fact that they are improving is a great sign,” he said. “Hopefully they will make a full recovery.”