Teen ‘Blasts Away’ Parts of Retina by Staring Into a Pet’s Laser Pointer

The dangers of staring directly into laser pointers are well documented, but an unfortunate incident involving a teenager from Ohio serves as a sobering reminder of just how little it takes to cause permanent damage to your eyes and vision.

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Looks like a job for molecular engineering.

Oh well.

Divine Angel said:

Oh well.

The lasers strength doesn’t not need to be that high for indoor animal use

if people can damage their eyes, it can happen to animals too.

better to get low powered ones, keep the high powered ones expensive or requiring a licence

Tau.Neutrino said:

Divine Angel said:

Oh well.

The lasers strength doesn’t not need to be that high for indoor animal use

if people can damage their eyes, it can happen to animals too.

better to get low powered ones, keep the high powered ones expensive or requiring a licence

I have no idea how low a laser can go or for that matter how high a laser can go in the safe range.

what about very stable geniuses that stare at solar eclipses

SCIENCE said:

what about very stable geniuses that stare at solar eclipses

It burnt his brain that’s for sure.

SCIENCE said:

what about very stable geniuses that stare at solar eclipses

Fortunately he doesn’t have a pet

“Handheld lasers can range in power from <5 mW (typical laser pointers) to >1,200 mW (high power blue lasers capable of lighting cigarettes or remotely igniting fireworks),

Does anyone know the safe range of light that the eye can take ?

Tau.Neutrino said:

“Handheld lasers can range in power from <5 mW (typical laser pointers) to >1,200 mW (high power blue lasers capable of lighting cigarettes or remotely igniting fireworks),

Does anyone know the safe range of light that the eye can take ?

sunlight on the plains but not in the snow

SCIENCE said:

Tau.Neutrino said:

“Handheld lasers can range in power from <5 mW (typical laser pointers) to >1,200 mW (high power blue lasers capable of lighting cigarettes or remotely igniting fireworks),

Does anyone know the safe range of light that the eye can take ?

sunlight on the plains but not in the snow

from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222423/

The safe range of light, to avoid exposing the eye to potentially damaging UV light, is approximately 2000 to 3500K and greater than 500 nanometers. The warmer incandescent lights are usually less than 3500K and are less damaging to the eye, but they often produce light that is inadequate for concentrating at work.

But how does that translate to in laser power ? milliwatts

Heres an interesting article

What are the limits of human vision?
https://www.bbc.com/future/article/20150727-what-are-the-limits-of-human-vision

doesn’t have my question or answer, Ill keep looking.

There is intensity across the whole eye range isn’t there?

example laser colours can be any colour at 5mv upwards

Tau.Neutrino said:

Teen ‘Blasts Away’ Parts of Retina by Staring Into a Pet’s Laser Pointer

The dangers of staring directly into laser pointers are well documented, but an unfortunate incident involving a teenager from Ohio serves as a sobering reminder of just how little it takes to cause permanent damage to your eyes and vision.

more…

>>On a subsequent visit six months later, his visual acuity was found to have improved to a normal level in both eyes, but that seemingly positive result didn’t reflect the harm done inside the eye.<<

So functionally normal. Good thing it was “only a few seconds”.

another interesting article

LED light can damage eyes, health authority warns
https://medicalxpress.com/news/2019-05-eyes-health-authority.html

Intensity in light is measured is Lux or lumens

is there some equivalent for milliwatt lasers ?

https://www.ophiropt.com/blog/laser-measurement/a-quick-guide-to-optical-measurement-devices/

Bogsnorkler said:

https://www.ophiropt.com/blog/laser-measurement/a-quick-guide-to-optical-measurement-devices/

Thanks, that’s very interesting, I’m getting closer.

Im now looking for lumen to milliwatt conversion

Lumens to watts calculator
https://www.rapidtables.com/calc/light/lumen-to-watt-calculator.html

try retinal photic injury

Coupla things to take into account:

a) short wavelength EM is generally more damaging to the retina than long, at the same level of power.
b) wavelength of maximum pupillary light response is around 500 nm and it tapers off pretty sharply in the near ultraviolet. So a high temperature source, relatively rich in ultraviolets, will be dangerous as the pupil will not constrict much.

SCIENCE said:

try retinal photic injury

no thanks

dv said:

Coupla things to take into account:

a) short wavelength EM is generally more damaging to the retina than long, at the same level of power.
b) wavelength of maximum pupillary light response is around 500 nm and it tapers off pretty sharply in the near ultraviolet. So a high temperature source, relatively rich in ultraviolets, will be dangerous as the pupil will not constrict much.

Yes webites are saying blue to ultrvoilet is more danerous

Im finding interesting information

https://www.quora.com/Will-staring-at-a-super-bright-light-damage-your-eyes-If-so-how-many-lumens-of-light-is-it-necessary

Safe to say the amount of lumens needed to damage your eye is in the tens of thousands, as anything over 4000 will make you squint, and anything in the hundred thousands is in laser territory.

Im getting the feeling its difficult to answer because of variables

At what LUX/LUMEN LEVEL will EYE DAMAGE likely occur?…….

How many lumens/lux to cause permanent eye damage / blindness?

What is the maximum light intensity that a human eye can withstand without being damaged?
https://www.quora.com/What-is-the-maximum-light-intensity-that-a-human-eye-can-withstand-without-being-damaged

more interesting articles

Human eye sensitivity and photometric quantities
https://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/Sample-Chapter.pdf

The All Important 1,000 LUX Rule
https://endmyopia.org/the-all-important-1000-lux-rule/

How much energy is required to blind someone?
https://biology.stackexchange.com/questions/19789/how-much-energy-is-required-to-blind-someone

one way to help with this problem is building in a range finder like on cameras but built into the laser pointer so that it doesn’t work on short distances only longer distances

Tau.Neutrino said:

one way to help with this problem is building in a range finder like on cameras but built into the laser pointer so that it doesn’t work on short distances only longer distances

It would add a little cost to making the laser pointer but would make it safer to use

close sensing devices are getting cheaper and are getting better at their jobs

the variables are listed here

From: Bogsnorkler link

https://www.ophiropt.com/blog/laser-measurement/a-quick-guide-to-optical-measurement-devices/

Radiometry versus Photometry

Let’s start with something concrete and easily defined. There are two ways to analyze light:

Radiometrically – this refers to the objective measure of light, not dependent on the subject (viewer) or the wavelength. Radiometry uses the classic units likeWatts (power) and Joules (energy). Photometrically – this refers to the subjective measure of light, as seen by the human eye. As such, all wavelengths other than visible will be measured as zero. The three most commonly-used photometric units are:

A. Lumen (lm) to measure “luminous flux” which is analogous to radiometric power

B. Candela (cd) to measure “luminous intensity” which is flux in a specific direction . (solid angle).

C. Lux to measure “luminance” which is flux that hits a given area.

This is why I am so far

If my facts are right, around 1000 lux is light sitting in the shade on a sunny day

4000 lux and above is considered dangerous

There are variables involved because of intensity, distance and area.

Sunlight falls on half the planet

Lasers are concentrated beams

from the first post

“Handheld lasers can range in power from <5 mW (typical laser pointers) to >1,200 mW (high power blue lasers capable of lighting cigarettes or remotely igniting fireworks),

the Lumens to watts calculator requires two inputs to require an answer.

Enter luminous flux in lumens:
enter luminous efficacy in lumens per watt:

Problem is that you can turn a readily available non handheld laser into a handheld(ish) one quite readily, just add 12v and you can get up around 30w
I have two over 5 W and and am waiting for a third rated at 30w for the cnc for cutting timber

boppa said:

Problem is that you can turn a readily available non handheld laser into a handheld(ish) one quite readily, just add 12v and you can get up around 30w
I have two over 5 W and and am waiting for a third rated at 30w for the cnc for cutting timber

Yes electronic fidlers can do lots of tricks.

I meant the general retail market.

I find the science interesting. Learning on the fly is interesting too.

Tau.Neutrino said:

“Handheld lasers can range in power from <5 mW (typical laser pointers) to >1,200 mW (high power blue lasers capable of lighting cigarettes or remotely igniting fireworks),

Does anyone know the safe range of light that the eye can take ?

There is an international standard that deals with this, I think. For the USA it’s ANSI Z136.

The key is how much energy is absorbed by the retina before the blink reflex (glare aversion response to bright lights) takes effect. The blink reflex takes around 0.1 seconds according to wikipedia.

Would the blink reflex react to an IR laser? I think it would, thoungh not perhaps as fast as as optical laser.

“Class 2. A Class 2 laser is considered to be safe because the blink reflex will limit the exposure to no more than 0.25 seconds. It only applies to visible-light lasers (400–700 nm). Class-2 lasers are limited to 1 mW continuous wave”. Laser pointers are supposed to be Class 2 lasers, but I have seen an old study where several laser pointers bought off ebay had a measured brightness exceeding the 1 mW limit. Do not stare into laser.

Maximum permissible exposure (MPE) at the cornea for a collimated laser beam according to IEC 60825, as energy density versus exposure time for various wavelengths.

Have a look at this graph, and feed in 0.25 seconds. For optical frequencies the maximum permissible exposure is 6e-4 joules per square cm.

“A Class 3R laser is considered safe if handled carefully, with restricted beam viewing. With a class 3R laser, the MPE can be exceeded, but with a low risk of injury. Visible continuous lasers in Class 3R are limited to 5 mW.”