CVNet - query on laser pointers

CVNet (cvnet@skivs.ski.org)
Thu, 18 Dec 97 01:47:04 PST

From: "Lawrence H. Snyder" <larry@eye-hand.wustl.edu>
To: cvnet@skivs.ski.org
Subject: Laser pointers

A company I deal with had a customer send them a clipping
from a British newspaper. The company, which sells equipment
for home laser light shows (including inexpensive mirror
galvonometers, which I use for generating moving visual stimuli),
asked if I could provide an authoritative rebuttal to the article,
which had apparently scared one of their potential customers.
While some points are obviously wrong, and I'm fairly sure the
entire article is fiction, I'd like to have some hard facts in
hand before going on record.

The article states that a cat was blinded by having a "laser pen"
shown in its eyes, and quotes the owner of the cat: "The poor
cat was screaming and must have been in appalling pain.
The vet told me the backs of his eyes have been completely
burnt out." The article goes on to say that the "infra-red
beam [of a "laser pen"] can be 100 times stronger than the
sun's rays", and implies that laser pointers should be banned.

Can anyone comment on how long an exposure to a 630-670 nm
laser pointer beam would be required to produce a pinpoint scotoma
in man? In cat? And can anyone comment on the intensity
of a pointer compared to sunlight, particularly in the infra-red
range?

Thanks,
Larry

-- 
Lawrence H. Snyder                    	     larry@eye-hand.wustl.edu
Assistant Professor of Neurobiology
Washington University, School of Medicine      Office:  (314) 747-3530
Dept of Anatomy & Neurobiology,  Box 8108      Lab:     (314) 747-4095
660 S Euclid Ave, St. Louis, MO 63110          Fax:     (314) 747-3436