Shortly after the burgeoning crowd of demonstrators moved to the basketball area, what appeared to be a Sikorsky MH-60G Pavehawk helicopter (possibly from the Portland Air National Guard) began flying menacingly overhead. I have never attended a demonstration where a military helicopter was visible. Police and media, yes - military, no. [Please note that the mission of the Pavehawk is special operations and combat search and rescue. They "come standard" with 7.62mm guns.]
The helicopter made several passes around and over the park, its long refueling probe and forward looking infra-red (FLIR) pod visible on the nose. The port side door was open and some onboard personnel could be seen inside. Considering the intimidation this helicopter was meant to elicit, it obviously warranted documentation. For the most part I chose to use my camera's optical viewfinder - as opposed to the LCD screen - to conserve battery power.
I moved to a slight hill before the Pavehawk executed a low, lazy pass over the park, approximately above the covered basketball courts. As I zoomed in close on the helicopter I felt a sudden discomfort in my right eye - the eye pressed up against the viewfinder. I quickly moved the camera away from my face, blinking my eyes, and for about 10 seconds my right eye would not focus. It quickly returned to normal, but I had no doubt something from the helicopter had caused it.
I did not really feel any pain, but as I said there was distinct discomfort. I have never experienced this sensation using this or any other camera (photography is a hobby of mine). At the time the sensation occured I was zoomed in quite tight on the Pavehawk, on the port side, the side with the open door.
[Others have mentioned there was a red light visible through that door, but from my military experience that is likely a status light of some type (i.e. open door indicator), or a navigation light (red is for left side, green if for right).]
After that little "waker upper" I used my LCD screen for further shots of the helicopter, and I never experienced that discomfort again (though I used the optical viewfinder for most of the day). If this helicopter was a special operations Pavehawk it could be equipped with various laser counter-measures that special operations squadrons need in hostile environments. However, I saw nothing to prove that what I experienced was an intentional act.
Following several incidents in 1997 and 1998, US military helicopter crews are now issued special glasses or goggles to protect against eye injuries caused by lasers. However, people on the ground are vulnerable to the lasers used on military aircraft and fighting vehicles. According to a November, 1998, VOA report:
JOHN PIKE STUDIES STRATEGIC ISSUES FOR THE FEDERATION OF AMERICAN SCIENTISTS. HE SAYS FOUR THOUSAND IRANIAN SOLDIERS SUFFERED EYE INJURIES, INCLUDING BLINDNESS, WHEN IRAQI FORCES SWEPT POWERFUL LASERS ACROSS THEIR RANKS DURING THE IRAN-IRAQ WAR.
LASERS ARE USED BY MANY NATIONS, INCLUDING THE UNITED STATES, IN TANKS, ANTI-AIRCRAFT WEAPONS AND TO DISRUPT ELECTRONIC DEVICES. MR. PIKE SAYS RECENT TREATIES LABELED WEAPONS SPECIFICALLY DESIGNED TO BLIND SOLDIERS AS 'INHUMANE' AND BANNED THEIR USE. BUT HE SAYS WITH SO MANY LASERS PLAYING SO MANY BATTLEFIELD ROLES, IT WILL BE DIFFICULT TO ENFORCE THE BAN ON THESE WEAPONS.
We do know that military aircraft are equipped with various laser devices that collect information and read terrain (specifically, range finders and laser image mapping). I may have accidentally caught some of that as the Pavehawk's onboard computer systems were scanning the ground. Then again, it may have been intentional to discourage the dozens of cameras aimed at the helicopter. In the present political environment and crackdown on dissent, the illegal use of laser countermeasures on peaceful protest can't be discounted. As a result, I would recommend that at no time should someone use an optical viewfinder to film military or law enforcement aircraft.