Greetings!
My name is Tom. I would really appreciate some feedback regarding the possibility of such a project.
The thing is; epilepsy, migraine and several other neurologic conditions are triggered by flickering light. This is a well established fact. Classic fluorescent/discharge tubes flicker on about
60-120hz rate, while modern light bulbs filcker in khz range (there is some residual low frequency flicker that still causes problems).Since flickering light are major disability factor for me, I wouldlike to know if it possible somehow to counter/filter/block/neutralize the flicker of such lamps. (there is of course an option to simply change the light sources, but as you might guess this can=92t be done).
There was some research done with special tints that block certain frequencies (and hence neutralize the amplitude). But these tints proved to be ineffective.
I=92m familiar with only one attempt of a anti-flicker design. It=92s seems rather primitive. Here is a copy of passage (it=92s a bit long, but bare with me)- from =93Photosensitive epilepsy=94 by Harding and Jeavons
" The spectacle lens consisted of three components. The first was a photosensitive absorptive lens which reduced the range of brightness encountered and helped compen=ACsate for variations in the relation of the secondary stimulating light source and the luminance of the hazardous flicker. It seemed that an overall attenuation was beneficial on sunny days, whereas minimal or no attenuation was necessary for indoor situations such as viewing TV. The next layer was a thin polarizing film designed to exclude the contribution of specular reflections which arose from horizontal surfaces and were often the source of low frequency pulses of high luminance, e.g. rippling water reflecting sunlight. The third component of the lens was an optical correction incorporating prismatic and dioptic power to correct the patient's refractive error and any residual aberrations induced by oblique viewing through the reflector.
Although the use of a spectacle frame design which completely blocks the temporal peripheral visual field might constitute a safety hazard, protection from stimulation in this direction was thought at that time to be important. For this reason we used thin photosensitive absorptive panels at the side to attenuate brightness, and an aluminized inner surface to equate its transmission with that of the frontal lens system and to reflect the light source approximately toward the pupil. The aluminized film may also slightly enhance the speed of response of the photosensitive absorptive side panels. There was a rigid wrap-round portion to the frame, and the side was hinged about 25 mm from the front to produce folding spectacles. They were, however, far larger when folded than conventional spectacles.
In our initial studies of 12 patients, the anti-flicker glasses removed the PPR to IPS in every case. Since the photochrome layer is slow and could not possibly respond to the flash rate of the photostimulator. this was achieved by the contrast illumination of the light bulbs alone. The procedure was that we first established the frequency which would consistently provoke a PPR with the patient wearing the glasses but with the flicker-sensing circuit switched off. This circuit was then switched on and IPS was repeated. The provocative flash rate was tested on a number of occasions and then the circuit was switched off. The IPS was then repeated and a PPR obtained on each occasion. Although the glasses were found to be entirely effective they were not cosmetically attractive. In addition, the construction of the spherical half-silvered mirrors was difficult and some simpler method of providing a relatively stabilized illumination in front of the pupil was desirable. Wc therefore began working on a modified design. The main prob=AClem in simplifying construction was to provide an alternative means of channelling light into the eyes in such a way that its effectiveness would be independent of eye position. A thin plate of clear perspex (1.6 mm) was fastened to the rear of the spectacle frame, and the edge of the perspex was ground to give a 45=B0 prism which passed obliquely in front of the centre of the eye. The spectacle frame, which was fairly thick, was drilled, and two bulbs were positioned one above and one below the joint of the side frame (Fig. 6.13). Channels were drilled in the frame to connect the bulbs in series using the side frames as part of the circuit. The bulbs were
3mm tubular wire-ended full spectrum bulbs. They required a supply of 5 V, 0.05 A, giving a life of 100.000 hours. Holes were drilled in ihe perspex plale so lhat this fitted over the two bulbs on each side. Thus when the bulbs were illuminated, the light was internally reflected in the thin perspex plate, and then reflected off the 45" prism into the eye. The oblique prism was positioned to bisect the pupil, but complete light stabilization could not be achieved, and a compromise was reached in which the light was stabilized with respect to eye movement in the majority of inferior and superior positions. Since the prismatic edge was narrow there was minimal interference with normal vision... etc. "Anyway; your thoughts on such a project?
Many thanks for reading.
Best regards.