What to do if you get pepper sprayed
Pepper spray has become a popular law enforcement and self-defence tool because of its availability and ease of use.
That's all very well when someone is under threat and wants to defend themselves from an attacker, but the proliferation of the use of pepper spray by Hong Kong police in recent months has raised concerns that it's being overused as a method of crowd control, especially during protest rallies.
As recently as June police controversially used pepper spray to scatter protesters at the government headquarters in an angry rally against plans for a new town development.
We have all seen TV images of protesters being the unfortunate targets of pepper spray and their quick reaction is to use water to flush their eyes. Wrong, wrong, wrong.
First of all, and most importantly, don't touch the affected area. Pepper spray is oil-based and can easily spread to other parts of the body by touch.
The last thing you want is to douse your eyes with water. Because pepper spray is an oil, and oil and water don't mix.
If you were sprayed in the face with pepper spray, you would immediately feel a burning sensation in your eyes, nose and mouth, and possibly even your throat and on your skin. It's like having an onion rubbed against your eyes.
The stinging, if left untreated, can last from 45 to 60 minutes. Your eyes would become irritated and probably swell shut, causing temporary blindness that can last up to 30 minutes. Immobilising people this way quickly allows the police to control a crowd. That, of course, is the purpose of using the pepper spray.
Dousing your eyes with water will flush and move the pepper spray particles around and scratch the surface of the cornea. It may even flush more particles from the face into the eyes causing even more pain. And if the water is unclean it may cause inflammation and prolong the suffering.
The best way to handle the situation is to keep blinking to allow the natural production of tears wash away the spray particles; don't rub your eyes with anything.
It's particularly a concern for those who wear contact lenses. If they are sprayed it would be even more painful if they instinctively rub their eyes as the particles and lenses will rub against the cornea.
The severity of the effects of pepper spray varies depending upon the amount used, the strength of the spray and where it's sprayed. If sprayed directly into a person's face, the effects may be more intense or longer lasting. Concerns have been raised about a number of deaths where the victim being pepper sprayed may have been a contributing factor. The actual compound, however, is not lethal.
However, studies show that some people may suffer more than others. For example, if a person is allergic to any of the ingredients in the pepper spray, has asthma, or suffers from a heart condition, then the effects may be more severe.
Dr Jeff Hui Yung-lam is a Hong Kong-based ophthalmologist