Mayo Clinic ophthalmologists have found that commercially available Class 3A green laser pointers can cause visible harm to the eye's retina with exposures as short as 60 seconds.
Dennis Robertson, MD, 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. The findings were published in the Archives of Ophthalmology.



So, If you have ever been briefly hit in the eye with such a pointer you know 60 seconds exposure will not 'short'.... A brief (.25 seconds- blink reflex time) exposure can temporarily blind, but that is unacceptable if you are a pilot trying to land...