To: "'Mounted search and rescue'" <msar-riders@lists.ibiblio.org>
Subject: [MSAR] Night vision /Flashlights
Date: Sun, 14 Mar 2010 17:24:30 -0400
While it is true that as people age night vision decreases, it is also true
that night blindness is very rare. Objects can be seen at night only if they
are either lighter or darker than their background and can be discriminated
by subtle differences in contrast. Many SAR personal now use flash lights
with red or green lens to enhance night vision. The commonly used white
does impair night vision, but night vision is based upon rods and cones with
the human eye. There are about 90 million rod cells in the human retina.
More sensitive than cone cells, rod cells are almost entirely responsible
for night vision.
-----Original Message-----
From: msar-riders-bounces@lists.ibiblio.org
[mailto:msar-riders-bounces@lists.ibiblio.org]On Behalf Of Una Smith
Sent: Sunday, March 14, 2010 9:53 AM
To: Mounted search and rescue
Subject: Re: [MSAR] BackPack Question
Barry Wells wrote:
>Why would you not use a flashlight?