From: jobst.brandt@stanfordalumni.org
Subject: Re: Best Eyewear?
Newsgroups: rec.bicycles.tech
Message-ID: <gwCZa.10428$dk4.416136@typhoon.sonic.net>
Date: Mon, 11 Aug 2003 01:42:36 GMT

Mike Jacoubowsky writes:

>> I wear Native Nano. Best glasses I have ever had. Polarized lenses,
>> light weight, fit very well and never slide no matter how sweaty I
>> get.

> Polarized lenses can get you into trouble; my last serious crash was
> caused by not seeing gravel on the road because the road was twisty
> enough, and the reflected light at an appropriate angle such that
> the lenses caused drastic shifts in transmitted light, so much so
> that you could barely see at times.

Ahhh, there are more dangerous effects than what you experienced.
Most reflected light from the road is strongly polarized and of
reflected light, that from a wet road is one of the most important
ones.  I was given a pair of polarized glasses to try and the first
road on which I tried them was the Giovo mountain pass in south Tirol,
just after a morning rain shower... in the woods.  By the time I
rounded two hairpin turns I knew I couldn't ride with them because
there was no way of detecting whether the road was wet or dry.  The
appearance changed between shade and sunlight and the effects reversed
after each 180 hairpin turn.

If you like to descend fast, don't use Polaroid glasses.  They block
valuable information of the road surface, even though they may be good
for the eyes.  I choose not to wear glasses at all, especially in rain
or snow.  I have not experienced any of the horrible eye injuries that
glasses proponents describe and I have ridden many miles in most every
condition.  Following a car on a dirt road is one case where I would
use goggles as the ancients did in the TdF before Greg Lemond
introduced Oakley glasses to the sport.  Since I am not racing, I
don't follow cars on dirt roads because I don't want to be a dust
bunny at the end of the ride.

http://www-math.science.unitn.it/Bike/Countries/Europe/Tour_Reports/Tour_of_the_Al

Jobst Brandt jobst.brandt@stanfordalumni.org Palo Alto CA

From: jobst.brandt@stanfordalumni.org
Subject: Re: polarized sunglasses
Newsgroups: rec.bicycles.misc
Message-ID: <CGzkd.4581$_3.55259@typhoon.sonic.net>
Date: Thu, 11 Nov 2004 01:57:54 GMT

Pat? in TX wrote:

>> I thought I had found the perfect sunglasses: they're polarized and
>> the lenses are barely tan (so as not to make the day look
>> darker). Today was the first day I have tried riding my bike with
>> the new glasses.  I can't read my bicycle computer while wearing
>> them!  The polarization makes a black smear across the front of the
>> cyclocomputer! When I take off the glasses, the screen of the
>> computer looks just fine.

LCD (Liquid Crystal Displays) work in that they alter polarization in
the display so that reflected light is canceled.  That is, it gets
polarized on the way in from outside, reflects off the mirror behind
the display liquid changing its polarization so that portion of the
display is dark (black).  Adding another polarizer (glasses)
interferes with seeing the displayed characters.

>> Has anyone else had this problem?

Anyone who uses Polaroid glasses will.  Try rotating the glasses at a
distance in front of the display.  Also, if you hold the glasses
directly on the display it will also not work.

Jobst Brandt
jobst.brandt@stanfordalumni.org