Laurent Theron is shouting at two policemen and waving his arms around for emphasis. From a distance, he looks more like a guy arguing over a parking ticket than a man who just suffered an injury that will leave him permanently blind in his right eye.

Last Thursday (September 15th), just a few minutes before he began yelling at the cops, Theron, a 46-year-old union activist, was with thousands of others in the Place de Republique, one of the main squares in Paris. He was protesting against a controversial new labor law in France when a projectile crashed into his face. Theron stumbled out of the square looking for help and that's when he met the cops and a couple of reporters, including me. To look at the wound was stomach turning. I couldn't help but pity him, knowing that he probably was going to lose the eye.

Already, the area around the eye was grotesquely swollen. The eye itself was pierced and slashed.

"Look at me," Theron yelled at the officers. "You shot me."

Theron later told French news outlets that he suspected he was hit by a teargas canister fired from a launcher. But video taken of the incident, as well as statements by witnesses, indicate he was more likely injured by a fragment from what the French call a "désencerclement grenade."

To scatter crowds, French police employ an explosive designed to cause an ear-splitting bang along with a blast of rubber shrapnel in a 10-meter radius. The video appears to show that one of these grenades detonated not far from Theron just before he collapsed. This kind of supposedly "non-lethal" explosive is popular with police around the world. The idea behind them is to disorient and frighten, not seriously injure.

Only, what happened to Theron is no freak accident. From the Arab Spring to Black Lives Matter demonstrations, Theron is just one of the thousands of people who have been maimed or killed in recent years by weapons that aren't supposed to cause great bodily injury.

How best to respond to a protest is almost certainly on the minds of authorities in Charlotte, North Carolina today. The fatal shooting Tuesday of 43-year-old Keith Lamont Scott sparked a second night of violent protests and looting Wednesday night in downtown Charlotte. Police responded by deploying tear gas, and the state’s governor activated the national guard. It’s already a familiar pattern among controversial police shootings involving unarmed black men: Scott’s family says he was unarmed, while police say he was armed and dangerous.

In 2014, the demonstrations that followed the shooting death of Michael Brown in Ferguson, Missouri led to 10 protesters and six policemen being injured. The police response to peaceful protest looked like a military occupation. Heavy-handed responses to demonstrations, especially peaceful ones, can ignite more violence or turn public opinion against leaders. That's why governments are searching for new ways to quell riots or violent protests without the use of deadly force. But options are limited.

"Lethal in Disguise," a report released in March on crowd-control weapons (CCWs) by Physicians for Human Rights and the International Network of Civil Liberties Organizations, was highly critical of CCWs and how they are used by police.

"The proliferation of CCWs without adequate regulation, training, monitoring, and/or accountability, has led to the widespread and routine use or misuse of these weapons," the authors wrote. "There is a pressing need to engage in further ethical research and empirical studies to develop clear scientific standards and parameters."

There’s already plenty of real-world evidence behind those findings. A year ago in Nepal, police fired rubber bullets at people protesting the country's new constitution. Four were killed, including a four-year-old child. During the 2013 protests in Brazil against price hikes on bus and train travel, one man lost the vision in his right eye when he was hit by a fragment from an explosive similar to France's désencerclement grenade. At the same protest, a photographer was hit by a rubber bullet and blinded in one eye.

Photographer Tali Mayer has taken portraits of the people who have been injured, many of them blinded, by "sponge bullets" fired by Israeli law enforcement. In Kashmir in 2014, Indian police drove off demonstrators by shooting pellets. Sometimes, the pellets just penetrated skin and other times they pierced eyes. The situation isn’t much better in wealthy countries with well-funded police forces.

Paris this year has seen some of its worst street fighting since 1968. Labor unions and leftist groups oppose the adoption of a new law that in part makes it easier for employers to lay off workers. A relatively small number have adopted tactics that include kicking in storefront windows, shattering bus stop enclosures, and pelting police with rocks, wine bottles, and Molotov cocktails. Two policemen suffered burns after being hit by cocktails during last Thursday's demonstration.

French cops typically respond with tear gas or by thwacking troublemakers with batons. When outnumbered and threatened, they are allowed to use désencerclement grenades. According to police policy, officers are required to roll the grenades into crowds to help limit the chances of head injuries. Nonetheless, in May a photographer suffered a facial injury when a grenade detonated near his head. Later that month, a freelance journalist spent a week in a coma after a grenade fragment crushed part of his skull.

Law enforcement’s appetite for less-lethal crowd control methods has created a huge opportunity for private companies, and some high-tech products have already entered the market. Two areas that have shown promise are acoustic weapons and directed energy devices, but like other less-lethal devices, they’re still controversial.

Acoustic weapons, sometimes called sonic cannons, are designed to direct loud noises over long distances. Typically they use large numbers of transducers to amplify and concentrate sounds that create discomfort in the human ear. Perhaps the best known of these devices is the Long Range Acoustic Device (LRAD). Police in Poland, India, Israel Oakland, California, and Ferguson, Missiouri, have reportedly used LRADs. But "less-lethal" doesn’t necessarily mean safe. In March, five people filed a lawsuit against the New York Police Department alleging they experienced nausea, headaches, and persistent ringing in their ears after police aimed an LRAD at protesters in December 2014. The manufacturer, LRAD Corp., has repeatedly said the device is safe and effective.

Then there's the "heat-ray." It works by focusing a beam of electromagnetic waves at a high frequency and short wave length. They are designed to create a burning sensation at the skin surface without penetrating deep and potentially damaging cells. But like sonic cannons, heat rays, tear gas, and non-lethal grenades, all of these technologies are capable of inflicting harm on entire crowds — making them especially problematic when used on people in lawful, peaceful gatherings.

Sadly, Laurent Theron became one of those unnecessary casualties. The video that shows when he was wounded doesn't indicate there was anybody nearby confronting or threatening police. He said that when he was hit, he was standing with his hands in his pockets.

"My eye was saved, but the vision was lost," he told French newspaper Liberation. "Anybody can lose an eye at a peaceful demonstration."