Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green laser pointer can cause eye damage

10.05.2005


Mayo Clinic ophthalmologists have found commercially available Class 3A green laser pointers can cause visible harm to the eye’s retina with exposures as short as 60 seconds. The findings will be published in the May issue of Archives of Ophthalmology.



Dennis Robertson, M.D., Mayo Clinic ophthalmologist, conducted investigations with a green laser pointer directed to the retina of a patient’s eye; the eye was scheduled for removal because of a malignancy. The green laser damaged the pigment layer of the retina, although it did not cause a measurable decrease in the visual function of the patient’s eye. Dr. Robertson believes that longer exposures could harm vision, however. He also warns about potential damage from higher-powered green laser pointers. "With the use of laser pointers that are more powerful than five milliwatts, there would likely be damage to the actual vision," he says. "Functional damage could occur within seconds."

Dr. Robertson does not advocate against use of green laser pointers; rather, he advocates against their misuse. "Green laser pointers are not a public health hazard at this time, but something people should be aware of," he says. "I’m raising concerns that people should be cautious when using green laser pointers not to point them at someone’s eye or face. It’s like how you use your knife -- carefully." While pointing out risks of green laser pointers, he adds, "This is a potential hazard to people’s eyes, but rarely is it going to be a practical hazard because the aversion reflex we have naturally will cause a person to blink or turn away from a laser light."


Green laser pointers are readily available in stores and on the Internet, according to Dr. Robertson. "Kids can buy these," he says. "They’re not strictly regulated." He adds that Class 3A green laser pointers are increasingly being used by amateur astronomers to pinpoint objects in the night sky and by the construction industry and architecture educators to point out details of structures in daylight. Dr. Robertson conducted the eye exposure test with a consenting patient two weeks before eye removal due to ring melanoma. The patient’s vision was 20/20, and the macular retina appeared healthy.

Dr. Robertson exposed the patient’s retina to light from a commercially available Class 3A green laser with an average power measured at less than five milliwatts: 60 seconds to the fovea, the center of acute vision; five minutes to a site 5 degrees below the fovea; and 15 minutes to a site 5 degrees above the fovea. Dr. Robertson had color photographs taken of the eye before and after exposure to the laser.

Dr. Robertson examined the patient’s eye 24 hours after laser exposure. He found retinal damage characterized by yellowish discoloration involving the pigment layer beneath the fovea and at the site of the 15-minute exposure above the fovea. Each of these sites developed a grainy texture within six days. Study of the eye tissue under a microscope also confirmed damage to the pigment layer in the laser-exposed regions.

Dr. Robertson has been interested in the effects of lights on the human eye during his career, testing operating room microscopes, lights used in the clinic, red laser pointers and now green laser pointers.

Previously, he determined red laser pointers to be quite safe. "I tested different powers up to five milliwatts and could not create recognizable damage in the human eye with the red laser pointers," he explains. "So, at least a transient exposure to red laser pointers’ light is only of trivial concern."

Dr. Robertson attributes the risk differential between red and green lasers to wavelength. "We know that the retina is infinitely more sensitive to shorter wavelengths," he says. "The green lasers appear much brighter to the human eye because of the shorter wavelength and can cause damage." Dr. Robertson says Mayo Clinic’s investigations have clearly demonstrated that green laser pointers can cause irreversible damage to the pigment layer of the retina.

Lisa Lucier | EurekAlert!
Further information:
http://www.mayo.edu
http://archopht.ama-assn.org

More articles from Health and Medicine:

nachricht New vaccine production could improve flu shot accuracy
25.07.2017 | Duke University

nachricht Chances to treat childhood dementia
24.07.2017 | Julius-Maximilians-Universität Würzburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>