Does anyone have information on reading effects and fluorescent lighting?
I have been doing a little research on the net just wondering what you all have.
Does anyone have information on reading effects and fluorescent lighting?
I have been doing a little research on the net just wondering what you all have.
Ever since fluorescent lighting was introduced in workplaces, there have been complaints about headaches, eye strain and general eye discomfort.
These complaints have been associated with the light flicker from fluorescent lights. When compared to regular fluorescent lights with magnetic ballasts, the use of high frequency electronic ballasts (20,000 Hz or higher) in fluorescent lights resulted in more than a 50% drop in complaints of eye strain and headaches.
There tended to be fewer complaints of headaches among workers on higher floors compared to those closer to ground level; that is, workers exposed to more natural light experienced fewer health effects.
[Wilkins, A. J., Nimmo-Smith, I., Slater, A. & Bedocs, L. (1989). Fluorescent lighting, headaches and eye-strain. Lighting Research and Technology, vol. 21, 11-18]
I have a friend that gets migraines unless she wear her plano pink glasses at work.
Chris:
Never tell anyone Pink is the perfect color. We have too many Optiboarders of this political persuasion already!
However I am sure that you remember B&L's pink and AO's rose which was origionally marketed as a lens to reduce glare off of paper (this was before flouresent lighting was very wide-spread) for proof-readers.
Chip
Years ago I sold fluorescent light bulbs. I remember one study that we used to sell specialty bulbs. This study revealed that the glare caused by standard fluorescent tubes, especially off of white surfaces such as paper, contributed to employee fatigue, lowering late afternoon productivity of office workers. We used this study to promote a specialty fluorescent tube that emitted a greenish tint. The study showed that by switching out the bulbs in offices, late afternoon productivity actually increased --quickly compensating the company for the cost of changing them out. I do realize that some of this is sales hype, but the green tint really did help.
Last edited by finefocus; 05-22-2008 at 01:27 PM. Reason: thought of something else
I think the B&L Version was called Softlite A & B.
Actually not a bad idea to sell lenses tinted in the colors for people working under daylight fluorecent light tubes, as they did when the illumination system started to be used.
There are a number of things to take into account when prescribing for flourescent light difficulties
1 The emmission curve of the light which can vary wildly (and spike migration makes it more complex)
2 The flicker frequency and modulation - temporal strobing - separation of pathways is necessary to ensure absolute levels of interpretation
3 The response of both cone cell and / or ganglion cells - ie colour responses
4 The relationship between magnocellular systems and parvocellular systems (to some extent dorsal v ventral streams)
5 Remittance and reflectance - task set - spatial strobing
6 Metamerism
7 Luminosity v colour space
It is totally inappropriate to assume one lens will fit all -to get it right, you have to test a variety of physiological responses - we use specialist instrumentation to achieve this and lenses have to vary from broad spectrum to band or notch filters. If you prescribe inappropriately then there can be significant physiological consequences.
It is possible to prescribe objectively as well as subjectively - eg EEGs will show significant arousal changes in real time depending on prescribing accuracy.
Jordan. ..............I know you are specialized in that field and know more about than all of us together.
However if one would want to make all the test' you describe above, you would have to go to patients home and place of work to check it all out in order to prescribe them the perfect color filter............which would result in more than one pair of glasses plus a lot of charges for the time spent to check all these different lightning conditions.
How would you propose a simple optician would handle such complex cases
We use additive methods to analyse optimum performance as an absolute envelope within the 3D colour space - and in some cases use a vectored version of the Pulfrich effect (a monocular depth modification caused by timing differences) either testsed haploscopically or binocularly.
- its just not possible to prescribe filters accurately unless you work to absolute levels (we use standardised CIE coordinates), factor in the ambient lighting - yes you do need to Know the lighting, factor in task - and then calculate the optimum lens. Its not necessary to visit workplace except in unusual crcumstances.
Sorry, currently, virtually all tinted lenses are prescribed using "poke and hope" methods - often this is OK - but it can have major effects on some patients, sometimes very bad. But in other cases properly prescribed tints will literally change peoples lives! A lot more tints will be used in the future - as drug replacements etc. Current prescribing methods will have to change, and the optical / optometric / ophthalmological professions will have a new tool - or significant threat! Tints can be extremely powerful - eventually everyone will have no option but to be profesional, the only question is how long will it take, and how many will get sued.
The tests we use are optometric (acuity, fields etc), physiological eg vestibular, cognitive eg in prosopagnosia etc, auditory (just finished very ineteresting clinical trial - results will be published in about a year), visual motor integration, AMPs, auto imumne clinical trials due soon, synesthetic tests, variations on the Mc Gurk effect, sequencing and mathematical matching in time and space. We can even assess optimum colour performance objectively.
It is relatively easy to determine optimum tints - understanding the mechanism is much more complex, but I am happy for anyone visiting Scotland to see methods in practice.
I will be presenting at optometrists national conference in Anaheim later this year, but only on using visual processing modification methods in special needs such as autism, dyslexia, dyspraxia, dyscalculia etc but would be happy to lecture / discuss privately for those interested in finding out about specialist assesment and prescribing methods in medical, optometric or patients with cognitive problems.
If you want to meet up contact me through practice website (it has some very interesting and unusual videos) www.jordanseyes.com
I intend to finalise my travel itinery in about a month
And the answer is yes - sometimes people do need extra specs, people do need to pay for time and expertise - but the benefits are so great that we have no problem charging. - we work on no win - no fee, and it is very rare that we don't get paid a fee!
Our patients love coming in too - and I get more chocolates/ cakes/wine as a thank you than you could imagine. Its a pity that I want to lose weight!
Last edited by Ian Jordan; 06-08-2008 at 07:02 AM.
Where do you hide the goards?
Sorry - don't understand. Is it pidgin English?
I can help with that, just send them to me. :D I love your site and find what you do very interesting.
There is a program in the file directory that you might find interesting. http://www.optiboard.com/forums/showthread.php?t=29082 their is a section on spectral analysis, which allows you to look at the CIE charts. I am still readin up on the subject and so far have been enlightened that this area of opticis still poses many challenges and areas for study. Good luck in all your studies and I enjoy checking out your site from time to time.
1st* HTML5 Tracer Software
1st Mac Compatible Tracer Software
1st Linux Compatible Tracer Software
*Dave at OptiVision has a web based tracer integration package that's awesome.
I work for Jonathan Paul Eyewear the makers of Fitovers. We had a lady call in about a month ago asking if we had anything that might help with Fluorescent Light Sensitivity. Honestly I hadn't heard of the ailment but we sent her a couple of Fitovers with our amber and gold lenses. She wrote back that our Gold lenses worked great. If you have any patients with this problem it might be worth checking out. The woman went on to write a lengthy testimonial for us, as she was so pleased with the results.
More info on our Trilenium Gold lenses by Eagle Eyes can be found on our website:
http://www.fitovers.com/index.php?page=lensTechnology
The best cure for this is the dreaded anti-greenie incandesent bulb, preferably bright enough to see with.
Chip
There used to be a set of colored lenses sold by Corning that would narrow the color/frequency down. The varied between a pink, orange/red, orange, and yellow/orange to address a few different spectrums of light. But I have not seen a set in many years.
It was great for Photophobic patients to figure out which tint worked the best for their light conditions.
Sharpstick
There are flourescent bulbs called "full spectrum" that emit a fuller and flatter color spectrum to mimic daylight that help immensely. They reduce color fatigue.
All the flourecent studies I could find use the old straight tube flouresent bulbs. In theory the newer twisted tubes could offset some of the "flashing" or pulsing of the older bulbs because although the bulb would still pulse, it would self cancel based on the variable distances of each part of the bulb.
The old tricks were to bring in some incandesant light to balance the flourescents pulsing, and use a Crux tint to balance the blueish color spectrum.
Sharpstick
This is an old thread back from 1941............. :D :bbg: :angry:
CPF by Corning.
http://www.visionadvantage.net/corningmedicaloptics.htm
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