Laser Radiation Bioeffects

[yew.sir-name]

Laser Radiation Bioeffects

found this http://radsafe.berkeley.edu/lsts1101e.html

i like the part where it says:

"Eye Injury Potential


The potential location of injury in the eye (see Appendix E - Eye Component Diagram) is directly related to the wavelength of the laser radiation. For laser radiation entering the eye:

Wavelengths shorter than 300 nm or longer than 1400 nm are absorbed in the cornea.

Wavelengths between 300 and 400 nm are absorbed in the aqueous humor, iris, lens, and vitreous humor.

Wavelengths between 400 nm and 1400 nm are focused onto the retina."

and

"Laser retinal injury can be severe because of the focal magnification (optical gain) of the eye that is approximately 105. This means that an irradiance of 1 mW/cm2 entering the eye will be effectively increased to 100 W/cm2 when it reaches the retina."

do you think they mean mw?

 

[SenKat]

Re:  Laser Radiation Bioeffects

Nope - WATTS ! It goes through a lense, man.....it's GONNA intensify the effect drastically....now some of my preaching about goggles makes sense ?

 

[pseudonomen137]

Re:  Laser Radiation Bioeffects

Yep and thats 100 W/cm^2. that means 1W/mm^2 which is closer to the dot size of our lasers. Also, as SenKat said, it gets focused. Lasers on our skin can sting, but its the same as hitting a balloon or something, you just get the dot in whatever concentration its in. Our eyes on the other hand are precision devices intended to focus light to a nice pinpoint onto our retina.... just think about that next time you consider buying goggles or not

 

[SenKat]

Re:  Laser Radiation Bioeffects

This topic is DEFINITELY worthy of "Stickiedom"...Yes, damnit - that IS a word ! *SenKat runs spell check, and adds it to dictionary...*

 

[yew.sir-name]

Re:  Laser Radiation Bioeffects

i got 'stuck' on LPF. woo

it does make me think. and once again instead of getting shades i've orderd a new laser (10mw green i posted in mods section) and other toys. they're on my list. cant put a price on sight. i want them goggles that seem too good to be true. 450-680nm. says they're designed for laser shows, od3 which is safe for anything under a watt, may be just as bad as sun glasses though and doesn't block ir. nor do wicked shades. i now want the ultimate in goggles. but i can use my camcorder for burning to keep me safe for now.

edit: not that i have anything to burn with yet, but my lasers do pop

 

[SenKat]

Re:  Laser Radiation Bioeffects

I DO personally recomend one pair of goggles for each wavelength - others may disagree with me on that, but I have a pair specifically for IR, green, and red....It took me a while to get there, but I tailored my experiments accordingly until I could get them all. Be safe !

 

[R._Morris]

Re:  Laser Radiation Bioeffects

When using the proper goggles are you able to see your beam or dot?
I'm thinking I need to break down and get a pair or 2..

Edit: Looks like most of my questions about goggles are answered in the next thread OD - A question

http://www.laserpointerforums.com/forums/YaBB.pl?num=1168012242

****EDIT FIXED LINK**** {SenKat wuz here !}

 

[SenKat]

Re:  Laser Radiation Bioeffects

Yes - to answer you anyways - buy the Wicked lasershades to be able to see the red lasers, and the sport elites are good for the greens - but so are the lasershades....matter of style, and the power of the lasers you will use with the green ones I guess....

 

[BlueFusion]

Re:  Laser Radiation Bioeffects

Lol SenKat you should try shining a laser through all your goggles, like, lined up. Or any light source for that matter.

 

[photongeek]

Re:  Laser Radiation Bioeffects

I DO personally recomend one pair of goggles for each wavelength - others may disagree with me on that, but I have a pair specifically for IR, green, and red....It took me a while to get there, but I tailored my experiments accordingly until I could get them all. Be safe !

I haven't seen the IR goggles Greg. What color are they and where did you get them. Thanks.

 

[spyrorocks]

Re:  Laser Radiation Bioeffects

If I remember correctly, IR goggles are a greyish color.

 

[FrothyChimp]

Re:  Laser Radiation Bioeffects

The color of the goggles are only meaningful when the goggle works by reflection. No useful goggle uses this means of reducing exposure. Chemists develop a range of chemicals that can absorb single or multiple wavelengths. Since the chemical composition varies by manufacturer the color of the lenses also vary based on the chemical makeup of the coatings and the combination of wavelengths and OD ratings for each wavelength the lens is designed to protect against.

 

[rocketparrotlet]

Re:  Laser Radiation Bioeffects

Whoa. Scary! Can staring at a 5mW green dot on the wall close up harm your eyes? Because I do it a lot. I was under the conviction that even a direct hit in the eyes can't do any real damage.

-Mark

 

[PyroEric]

Re:  Laser Radiation Bioeffects

1mW to 100W would be a gain of 100,000 not 105.

Sunlight at earths surface on a sunny day would be about 100 mW per square cm, according to this it would be somehow focused to 100,000 watts per square cm.

This would mean looking at the sun for a fraction of a second would flash vaporize a hole in your retina.

The eye does not focus light into a single point on the back of the retina like the picture might imply, the focal point is in between the lens and the retina so the image is projected over the retina, not just a tiny point.

Each eye also has a blind spot where the optic nerve is attached. You dont see a blind spot because your brain blends in the surrounding area. You can make two dots on a piece of white paper, when moved to the correct location while looking forward, the dots will disappear and that is where the blind spot is.

 

[davidgdg]

Re:  Laser Radiation Bioeffects

1mW to 100W would be a gain of 100,000  not 105.

Sunlight at earths surface on a sunny day would be about 100 mW per square cm, according to this it would be somehow focused to 100,000 watts per square cm.

This would mean looking at the sun for a fraction of a second would flash vaporize a hole in your retina.

The eye does not focus light into a single point on the back of the retina like the picture might imply, the focal point is in between the lens and the retina so the image is projected over the retina, not just a tiny point.

Each eye also has a blind spot where the optic nerve is attached. You dont see a blind spot because your brain blends in the surrounding area. You can make two dots on a piece of white paper, when moved to the correct location while looking forward, the dots will disappear and that is where the blind spot is.

The gain is indeed about 100,000, but the sun does not burn a hole in your retina because the sun is not a point source, unlike a laser beam. If the sun appeared as a point source then it certainly would[highlight][/highlight] burn a hole in your retina.

You are right that a laser beam is not literally focused to a dimensionless point on the retina. But the figures I have seen suggest that the retinal image size of a point source such as a laser is no more than a few microns across which still produces stupendous power levels per unit area for even a modest powered laser and orders of magnitude more than for a retinal solar image. Hence you can safely look at the sun for a few seconds but cannot do so for even a modestly powered laser.

 

[MarioMaster]

Re:  Laser Radiation Bioeffects

man lots of thread necro recently