Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy.

Elevated dark adaptation thresholds in traumatic brain injury.

Du T, Ciuffreda KJ, Kapoor N

Department of Vision Sciences, State University of New York/State College of Optometry, New York 10036, USA.

PRIMARY OBJECTIVE: To expand upon earlier findings of elevated dark adaptation (scotopic) thresholds in photosensitive individuals with traumatic brain injury (TBI). METHODS AND PROCEDURES: To assess scotopic thresholds in individuals with TBI (n = 17) manifesting varying degrees of photosensitivity (mild, moderate or marked), but without retinal dysfunction, to those of non-photosensitive, visually-normal individuals (n = 21) using a hand-held dark adaptometer. MAIN OUTCOMES AND RESULTS: The group mean scotopic threshold for the TBI group was significantly higher than that of the visually-normal group. Over 50% (nine out of 17) of the TBI group exhibited elevated thresholds. There was no correlation between the threshold value and degree of photosensitivity. CONCLUSION: The elevated scotopic thresholds suggest an abnormality in cortical gain control. An anomalous adaptive response may develop due to cortical damage, thereby attenuating subjective light sensation.

Published 15 November 2005 in Brain Inj, 19(13): 1125-38.
Full-text of this article is available online (may require subscription).

© 2005-2008 Optometry Research Today. All Rights Reserved.