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Background:The aim of our study was to measure the reading eye movements in 22 subjects with traumatic brain injury using ReadAlyzer. ReadAlyzer is an objective eye 23 movement recording device that tracks the eye movements while reading. 24Methods: Reading eye movements were measured using ReadAlyzer in 30 subjects 25 with traumatic brain injury (mild, moderate and severe) who had binocular vision and 26 reading related symptoms and 60 asymptomatic controls. 27Results: There was a significant decrease in reading eye movement parameters in 28 subjects with traumatic brain injury compared to controls. Reading eye movement 29 parameters were represented in median (IQR). Subjects with traumatic brain injury 30presented with an increased number of fixations/100 words: 137 (106-159) and 31 regressions/100 words: 24 (12-36), and reduced reading rate 154 (128-173) words per 32 minute. They also had a lesser grade level equivalent: 4.0 (3.0-7.0) and reduced 33 comprehension: 70 (60-80) percentage (Mann-Whitney U test, p<0.05). Reading eye 34 movement parameters were significantly affected in mild and moderate-severe 35 traumatic brain injury subjects compared to controls (Kruskal-Wallis test, p<0.05). 36 Conclusion:Reading eye movement performance using ReadAlyzer was found to be 37 decreased in traumatic brain injury. Reading assessment may serve as a clinical 38 measure to understand the oculomotor system due to traumatic brain injury. 39 40 41 3 Reading is one of the most important visual functions in daily living. The act of reading 42 is highly complex involving an integrated function of oculomotor, sensory, cognitive, 43 and attentional aspects. 1 Oculomotor system primarily involves execution of vergence, 44 versions and accommodation during fixations, reading, writing and while viewing any 45 target in the environment. 46 47 A normal reading is comprised of accurate, rhythmical and spontaneously executed 48 sequences of saccadic eye movements interspersed with brief fixational pauses. 1,2 49 Reading related saccadic eye movements are 1-3 degrees in amplitude and the 50 saccadic latencies are 30-60 msec. 2 The presence of accurate saccadic tracking, 51 synchronised ocular accommodation and vergence is required for efficient reading. 52 53 In traumatic brain injury (TBI), multiple brain areas and their functions are adversely 54 affected because of the diffuse axonal injury (DAI). A physical damage to the 55 underlying neurons, such as stretching, twisting, and shearing of the neurons can 56 cause an impairment resulting in a range of sensory, oculomotor, perceptual and 57 structural abnormalities. 1,3 58 59 Symptoms following TBI may persist for seconds to minutes after the event and usually 60 resolve within 12 weeks but may continue for months or even years. 4 Impairment of the 61 oculomotor subsystem following TBI, also adversely affects the naturalistic pattern of 62 reading. Ninety per cent of the visually symptomatic mild TBI (mTBI) group exhibited 63 oculomotor dysfunction (OMD) following the head trauma. 3...