Mayo Clinic ophthalmologists have found commercially available Class 3A green laser pointers, commonly used in the construction industry and by architects to point out details of structures in daylight, can cause visible harm to the eye’s retina with exposures as short as 60 seconds.
A Mayo researcher, Dennis Robertson, MD, 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, and while it did not cause a measurable decrease in the visual function of the patient’s eye, Robertson contended that longer exposures could harm vision. He also warned about potential damage from higher-powered green laser pointers.
With the use of laser pointers that are more powerful than 5 milliwatts, he found, there would likely be damage to the actual vision, and functional damage could occur within seconds.
Robertson reported that his findings, published in the May issue of the Archives of Ophthalmology (http://archopht.ama-assn.org), do not lead him to advise against the use of green laser pointers, but rather to advocate against their misuse.
In an earlier study, Robertson determined red laser pointers to be quite safe. He attributes the risk differential between red and green lasers to wavelength. “We know that the retina is infinitely more sensitive to shorter wavelengths,” he said. “The green lasers appear much brighter to the human eye because of the shorter wavelength and can cause damage.”