Light Flashing Effects Clinical Trial
Official title:
Study of the Effects of Light Flashes on the Visual System
Background The goal of this study is to examine the human visual and cognitive performance
under the effect of bright light pulses. Exposure to visual stimulation of such pulsation may
interfere with cognitive function and at certain situations this may be noticeable and may
interfere with our judgment and abilities. In some of them visual or cognitive impairment
from exposure to bright light flashes may result in catastrophic outcome due to the high-risk
situation e.g. road accidents. Ocular exposure to a bright light can result in profound
momentary transitional loss of vision. The light sources employed for visual stimulation in
this study will be restricted to the range consistent with "reversible effects" (e.g. glare
and flash insensitivity or "flash blindness").
The impact of an exposure to bright light depends not only on the exposure level and
frequency, but also on the exposed individual's activity, psychological state, adaptation
level and visual task. Glare is primarily caused by the scattering of light within the eye
due to the imperfect transparency of the optical components of the eye and to a lesser extent
by diffuse light passing through the scleral wall or the iris. The scattered light overlays
the retinal image, thus reducing visual contrast. Excessive glare may impair visual function
and lead to temporary disability.
The above mentioned effects of exposure to light and pulsating light stimulus on the visual
system and cognition were studied in detail by a number of groups. These studies indicate
that the visual and cognition effects of pulsating light are a function of the following
parameters: pulse duration, light intensity and pulse frequency.
Study Purpose and Rationale The purpose of this study is to evaluate the cognitive effects of
exposure to flashing light stimuli by measuring the response time and level of performance of
healthy human subjects during exposure to light pulsations.
Study Design and methods:
1. Overall study design An open prospective study comprising of cognitive tests performed
during and following exposure to bright flashing light stimuli.
Pre and post -cognitive test (within 1 month after the test) ophthalmological tests will
be conducted.
2. Study Participants A total of 60 subjects will be recruited for this study over a span
of 3 months.
The subjects will volunteer to participate in the study. Flash Tests The subject will be
positioned at a selected distance from a flashing unit and a screen on which different
scenarios will be projected.
The subject will be exposed to the flashing light generated by the study device with various
parameters (Pulse width, Repetition Rate (RR), Intensity). Static and dynamic targets, will
appear on the screen at random locations and the subject will be instructed to response by
aiming a narrow light beam at the targets on the screen. A CCD camera will capture the screen
scenarios.
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