SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Seamanship & Navigation (http://www.sailnet.com/forums/seamanship-navigation/)
-   -   transition lenses and lost bouy lights? (http://www.sailnet.com/forums/seamanship-navigation/65393-transition-lenses-lost-bouy-lights.html)

trailblazer1229 06-08-2010 09:00 AM

transition lenses and lost bouy lights?
 
Has anyone heard of this problem? A few weeks ago a sailing instructor brought to my attention a problem transition type eyeglasses may have during the evening/night time.

Apparently while sailing at night he was looking for a flashing bouy and knew it was close on his charts, but he could not see the flash. Something told him to pull his eyeglasses down and low and behold, he saw the bouy about 10 meters of the bow flashing bright as the morning Sun.

He figured the light was transitioning the glasses everytime it flashed. He made a comment about a collision that may have happened in the sailing community and the latest theory was that the lenses may have contributed to it.

Any ideas? Rumor? Myth? Opinon? Experiences?

nk235 06-08-2010 09:14 AM

I'm no expert on light transitioning glasses but my mother as well as a few of my friends wear them and they do not transition in the blink of an eye. They take a few seconds to transition from light to dark or vice versa depending on the light conditions but in no way does this happen rapidly. It leads me to believe that this aspect of the glasses did not have any affect on him not seeing the beacon. However it could have been the glasses possibly being blurry or the frames being in the way or maybe the GPS screen or some other light source was causing the glasses to be in a darkened state. I have been out many times fevourishly looking for a bouy that I knew was there and just not seeing it till the last second. (I don't wear glasses and have perfect vision). Sometimes being on the water in the night can play tricks with your eyes and mind. I think that is the more likely answer then the distant slight blink of a marker rapidly causing his glasses to shift from light to dark and then back to light again in a fraction of a second. Just my two cents.

-Nick

erps 06-08-2010 09:34 AM

I've been wearing transition lenses for 30 years and haven't experience anything like that. I have had my vision degraded by dirty glasses though.

trailblazer1229 06-08-2010 09:57 AM

Funny that you mention the GPS. He did as well. Perhaps the light from the monitor dimmed his glasses to a point he couldn't see the bouy when he looked up. Good to know.

SVAuspicious 06-08-2010 10:20 AM

Gross speculation here, but if the glasses are polarized presumably the polarization is independent of dimming. A private AtoN that uses an LED light might be cross-polarized and invisible through the glasses.

Dmclean 06-09-2010 02:09 PM

I work for Transitions Optical. Original Transitions lenses are activated only by UV light, not visible light or light emitted from a GPS unit and, as somebody else had mentioned the change is gradual, not instant. In my own personal experience, I know my glasses need a good cleaning from the salt spray every time I come off the water. Perhaps it was that, or just could’ve been a coincidence.

trailblazer1229 06-09-2010 04:33 PM

Quote:

Originally Posted by Dmclean (Post 611336)
I work for Transitions Optical. Original Transitions lenses are activated only by UV light, not visible light or light emitted from a GPS unit and, as somebody else had mentioned the change is gradual, not instant. In my own personal experience, I know my glasses need a good cleaning from the salt spray every time I come off the water. Perhaps it was that, or just could’ve been a coincidence.

Maybe we should get a techno-geek on this, but I am under the impression that LCDs and certainly CRTs (old style computer monitors) DO emit some UV light. Although the amount LCDs emits is less than CRTs. The UV in LCDs come from the flourescent lamps in them. The new LED LCDs don't have these flourescent lamps and apparently emit 0 UV.

However, I am not disputing the cause was other than this, I was just trying to get others experiences and thoughts. Answer me this Batman, staring at a GPS screen in the dark of night for extended periods of time, or staring at it to get a reading for say, 10-20 secs. Perhaps that is enough time to turn out the lights so to speak?

imagine2frolic 06-09-2010 06:36 PM

I just worked my way into Bahia de Cartegena in the middle of the night. Using eyesight with transition lesnses, binoculars 20 yrs old from Worst Marine, a laptop for a chart plotter. I have to agree with the others on the dirty lenses........i2f

AdamLein 06-09-2010 07:30 PM

The lenses wouldn't need to transition rapidly to block out the buoy light, as long as they were darkened by the time the wearer started actively looking for the buoy.

SVA: do you have a reason to believe that the light emitted from such LEDs might be polarized, or is that part of the speculation? The only ways I could think of polarizing the light would seem like unnecessary extra steps in the construction of such a buoy...

rockDAWG 06-09-2010 08:43 PM

Quote:

Originally Posted by SVAuspicious (Post 610864)
Gross speculation here, but if the glasses are polarized presumably the polarization is independent of dimming. A private AtoN that uses an LED light might be cross-polarized and invisible through the glasses.

My guess is also on the polarizing effect of the lens.


All times are GMT -4. The time now is 09:14 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012