T Du1, K J Ciuffreda, N Kapoor. 1. Department of Vision Sciences, State University of New York/State College of Optometry, New York 10036, USA.
Abstract
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.
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.
Authors: Natalie M Guley; Nobel A Del Mar; Tyler Ragsdale; Chunyan Li; Aaron M Perry; Bob M Moore; Marcia G Honig; Anton Reiner Journal: Exp Eye Res Date: 2019-03-26 Impact factor: 3.467
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