Mild traumatic brain injury (mTBI) from explosive devices has emerged as the major cause of morbidity for U.S. military during recent wars. The authors found similar prevalence of visual dysfunctions and associated symptoms in military at different stages following non-blast or blast-induced mTBI. Sadly, civilian and mTBI military sequelae can be expected to be quite similar.
Research Advocacy for Head Trauma-Induced Eye and Vision Disorders
Our invited authors advocate increased vision and eye education and research funding for TBI and concussive head injury. They point to the success in funding military TBI vision and eye consequences as an example of the success of advocacy in this area.
Timing and Vision Protection in TBI Treatment
Erythropoietin (EPO) is a promising neuroprotective agent in Phase III clinical trials for the treatment of traumatic brain injury. The authors suggest that EPO, at least in mice, may be protective of retinal neurons and axons if intraocular EPO is given 3 weeks post-injury, not at time of injury.
Superior Colliculus and Eye Movement Disorders Following Head Trauma
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder from brain injury and concussion. It has seen in repetitive head trauma induced in contact sports including boxing, American football, hockey, and wrestling, and also in military veterans exposed to blast shock waves from explosive devices. The authors' study suggests pathology in the superior colliculus is a consistent feature of CTE, which could give rise to eye movement problems in these cases.
Validating Survey for TBI Vision Symptoms
Our authors Rasch analysis of a visual symptom questionnaire yielded a one-dimensional scale that allowed development of a traumatic brain injury (TBI) threshold cutoff score threshold. Likert analysis yielded multidimensional symptom scales that identified unique patient profiles.
Characterizing TBI from Eye Movement Behavior
Diagnosis of TBI is based on MRI or computed tomography (CT) X-Ray imaging that can reveal large, often-irreversible structural damage to brain tissue. Our authors offer a new assessment, based on eye-movement behavior, to quantify, evaluate treatment and monitor recovery.
'Safe to Return-to-Play' Versus 'Safe to Return-to-Learn' After Concussion Vision Symptoms
Our authors' study looked at a cohort of children age 5-18 with post-concussion symptoms lasting longer than 10 days, to evaluate the association of vision symptoms to reported school difficulty. Their results indicate that vision symptoms are associated with academic difficulty after concussion.
Treating Post Concussion Vision Symptoms
For post-concussion patients referred from two private practices the most prevalent diagnoses were convergence insufficiency and accommodative insufficiency. Vision therapy had a successful or improved outcome in the vast majority of cases that completed treatment. The authors call for large clinical trials.
Objective Measures of Disparity Vergence for Concussion-Related Vision Changes
The authors suggest successful vision therapy after concussion-related convergence insufficiency and propose a 25-minute testing regime that could be used in a large-scale clinical trial with their objective assessments of disparity vergence.
How Well Does King Devick Test Repeat in Teenagers and Relate to Other Vision Functions?
The King-Devick Test (KD), primarily a saccadic eye movement and reading test, has been used as a "remove-from-play" sideline test for concussion in college-age athletes and older. However, our authors studied over 600 Birmingham Alabama junior high and high school athletes at a pre-season state mandated "physical screening" and found only poor correlation with other vision functions such as convergence, alignment and objective pupil function. They found KD is repeatable in group data but may be best used with individual player norming (e.g. with 4 measures) to provide guidance for future high school removal-from-play decisions.
Near Point of Convergence after Pediatric Concussion
Our authors studied the incidence of near point convergence disability (~24%) and its recovery course in 275 concussion patients presenting to a pediatric sports medicine clinic. The abnormal near point of convergence improved both with standard clinical care (almost half of them in about one month) and with formal vestibular therapy, including interventions for abnormal convergence training, in others (~40% in about 3 months). They advocate near point of convergence testing in all pediatric concussion patients.
Post Brain Injury Binocular Vision Disorders Responsive to Home-Based Therapy
The authors report adults (mean age 45) with post brain injury binocular vision disorders respond well to 12 weeks of home-based computer vergence therapy.
Chronic Photophobia Basis Following TBI
Photophobia is a common symptom in individuals suffering from traumatic brain injury (TBI). The authors were unable to support the hypothesis that blue intrinsically photosensitive retinal ganglion cells (ipRGCs) become "hypersensitive" to light following mild TBI. Greater test variability in these participants may have masked any significant effect.
When Not to Use an Eye Patch Following Brain Injury
Patching the left eye has been shown to worsen spatial judgments in some brain-injured patients with left spatial neglect (failure to respond, report, or orient to sensory stimuli located to the left) by inhibiting the right superior colliculus (SC). Our authors cite cases and provide a literature review arguing more peripheral parts of the visual field increasingly project to the contralateral SC with the temporal crescent being entirely contralateral, and suggest avoiding eye patching simply for the temporal crescent. In most cases taping off the spectacle lens avoids an eye patch.
Retrograde Degeneration of Retinal Ganglion Cells After Severe Brain Injury
Our authors describe a 25 year-old male diagnosed with transsynaptic retrograde degeneration of retinal ganglion cells 2 months after severe brain injury. Serial spectral-domain optical coherence tomography (SD-OCT) was able to track the course of progressive retinal nerve fiber layer loss in both eyes after the trauma.