Dozens of partygoers at an outdoor rave near Moscow have been partially blinded after a laser light show burned their retinas, say Russian health officials.
Moscow city health department officials say that 12 cases of laser blindness were recorded at the Central Ophthalmological Clinic in the city. The daily newspaper Kommersant reports that another 17 victims have registered at another hospital in the centre of the capital.
Ravers at the Aquamarine Open Air Festival in Kirzhach, 80 kilometres northeast of Moscow, began seeking medical help days after the show, complaining of eye and vision problems.
"They all have retinal burns, scarring is visible on them. Loss of vision in individual cases is as high as 80%, and regaining it is already impossible," Kommersant quoted a treating ophthalmologist as saying.
Partygoers say heavy rains forced organisers to erect massive tents for the all-night dance party. The damage seems to have been caused when laser beams that were intended for outdoor use to illuminate the sky, were somehow turned or reflected onto the crowd.
"I immediately had a spot like when you stare into the sun," attendee Dmitry told Kommersant.
"After three days I decided to go to the hospital. They examined me, asked if I had been at Open Air, and then put me straight in the hospital. I didn't even get to go home and get my stuff," he said.
Cosmic Connection, promoters of the Aquamarine rave, were unreachable for comment and did not list contact numbers on their website.
Powerful lasers can cause eye damage instantly by burning the delicate light sensitive cells in the retina or by heating the fluid in the eye, causing a small steam explosion.
Laser weapons that are intended to blind their victims were banned in 1998 by the United Nations but weapons that dazzle have so far escaped censure.
The owner of a Moscow laser rental company, Valentin Vasiliev, says the accidental blindings were due to "illiteracy on the part of technicians".
"It was partly the rain, but also partly the size of the laser. Somebody set up an extremely powerful laser for such a small space," he says, adding that his company did not provide the lasers at the Aquamarine event.
14 July 2008