Several manufacturers of diagnostic video eye tracing systems also have less expensive instruments for observing and videotaping eye movement during routine physical examinations. For example, many physicians perform the Dix-Hallpike maneuver during intitial history and physical examination. Since the test is performed with eyes open, so the examiner can view the eyes for any sign of abnormal movement, the patient can often suppress the nystagmus by fixating on something in the environment. Standard frenzel lenses improve the chances of observing abnormal eye movement but do not completely eliminate the chance for fixation suppression. The video frenzel lenses place the patient in total darkness.
Infrared light illuminates the eyes and miniature cameras magnify the eye image onto a TV monitor.
Test validity is greatly improved. Video frenzels can also be utilized during canolith repositioning maneuvers. It is also possible with some models to videotape the eye movements and have them analyzed at another time by the computer software of a complete diagnostic VNG system. This technology has revolutionized the field of vestibular diagnosis by improving the validity of the measures and increasing the chance to observe and record subtle yet pathological eye movement. IA can assist in the selection of the instrument that is most suited for your needs, both clinically and financially.