Visual disruption using the thermal lensing effect in the human eye: pilot study.
At select wavelengths, near infrared (IR) light is absorbed in the preretinal media of the eye. This produces small transient increases in temperature that temporarily alter the local index of refraction. If the IR exposure is sufficiently high, a momentary reduction in the focusing power of the eye can be induced through an effect known as thermal lensing. Fundamental optical interaction and safety aspects of this phenomenon have been demonstrated previously in animal and artificial eye models. However, whether the effect will induce an observable visual change in human subjects has not been explored. Here, results of a pilot study are shown where eight human subjects were exposed to an IR laser at levels that were below the safe exposure limit. The exposures did induce a transient visual distortion if sufficiently high levels were used. While the description of the visual change varied between subjects, this experiment was able to determine a general guideline for power needed to induce significant effects in human subjects.
Air Force Research Laboratory, Fort Sam Houston, Texas 78234, USA. eweber@utexas.edu
Erica L
EL
Towle
Paul V
PV
Garcia
Peter A
PA
Smith
Robert J
RJ
Thomas
Andrew K
AK
Dunn
Ashley J
AJ
Welch
Brian K
BK
Foutch
D000328:Adult; D000368:Aged; D006801:Humans; D007259:Infrared Rays; D007834:Lasers; D008875:Middle Aged; D010469:Perceptual Distortion / Q000528:radiation effects*; D010865:Pilot Projects; D012160:Retina / Q000528:radiation effects*; D013696:Temperature; D014794:Visual Fields / Q000528:radiation effects*