When 20/20 Isn’t Enough: Vision Changes After Brain Injury

Kara Christy, MS, OTRL, CBIS

The patient passed the eye exam. Acuity 20/20. Ocular health unremarkable. And yet three months post-injury, she still cannot get through a page of text, still feels nauseated walking the aisles at the grocery store, still cannot return to a job she performed competently for 11 years.

Her chart says “poor attention” and “low frustration tolerance.”

Her problem is that her eyes will not work together long enough to let her read.

This is the most common way vision gets missed after brain injury: we test the wrong thing, get a normal result, and attribute the resulting functional failure to cognition, motivation, or behavior. Passing a Snellen chart tells us the patient can resolve high-contrast letters at distance under ideal lighting. It tells us almost nothing about whether the visual system can do its actual job.

Vision is a hierarchy, and the foundation fails first

At the base sit acuity, visual fields, and oculomotor control: fixation, pursuits, saccades, scanning. Layered on that are the binocular skills, including convergence, divergence, vergence facility, and accommodation. Only above all of that do we reach visual attention, visual-spatial processing, and visual perception, the skills we tend to write goals for.

You cannot remediate a higher-order visual-perceptual deficit while the foundation underneath it is unstable. And because so much of rehabilitation is delivered visually, a broken foundation quietly degrades everything else we do. Cognitive retraining, physical therapy, and vocational work all assume the visual system can deliver clean, stable input. When it cannot, progress stalls, and the plateau gets attributed to the patient.

The visual hierarchy. Foundational oculomotor and binocular skills support the higher-order processing we typically write goals for.

How common, and why it goes unrecognized

Visual dysfunction occurs in roughly 50 to 70 percent of acquired brain injuries. A meta-analysis of TBI patients without concomitant eye injury found accommodative dysfunction in 42.8 percent and convergence insufficiency in 36.3 percent. Among adolescents evaluated after concussion, 69 percent carried at least one vision diagnosis.

One caution on a figure you will see quoted often. The claim that “90 percent of TBI patients have visual dysfunction” comes from a chart review of patients already referred to a vision clinic with vision symptoms. That is a real finding about that population, not a population prevalence. The 50 to 70 percent range is better supported, and still high enough to justify screening everyone.

Vision goes unrecognized for three reasons. A routine eye exam evaluates the health of the eye, not how efficiently the system performs sustained work. The symptoms present as something else: difficulty at near reads as poor attention, avoidance of reading as low motivation, overwhelm in a store as anxiety. And patients cannot report what they have no memory of losing.

What to watch for, and where to send them

 

Red flags any provider can observe, grouped by the daily activity in which they surface.

A brief functional screen is within OT and PT scope and takes minutes: pursuits and saccades for smoothness and accuracy, near point of convergence, diplopia, fields by confrontation, and accommodative amplitude to first sustained blur.

Symptoms persisting beyond about four weeks warrant a comprehensive neuro-optometric examination, which adds testing of eye teaming, accommodative function, tracking, and visual-spatial function. Find providers through the Neuro-Optometric Rehabilitation Association (noravisionrehab.org) or the Optometric Vision Development and Rehabilitation Association (covd.org), and ask whether they have brain injury experience; not all do.

What OT and PT address independently, what requires collaboration, and what belongs to optometry.

Remediation and compensation are both legitimate

Compensation makes the environment match the impaired system: enlarged text, increased contrast, scheduled visual rest, tinted or prismatic correction. It works immediately. Remediation improves the underlying skill through graded loading of the visual system; it is slower, and in our program typically runs two to three sessions weekly for four to six months. Most patients need both. The honest framing for families is that compensation buys function now while remediation works on capacity over months.

Be straight about the evidence

The Convergence Insufficiency Treatment Trial found office-based vergence and accommodative therapy with home reinforcement significantly outperformed home exercises and placebo, in children, not in a brain injury population. Tested in adults, objective measures improved, but symptom scores did not separate from placebo. A 2022 consensus statement from the American Academy of Ophthalmology and the North American Neuro-Ophthalmology Society rated the mTBI-specific evidence low certainty and specifically challenged the underpinnings of post-trauma vision syndrome and visual midline shift syndrome. A 2024 meta-analysis reached the same conclusion: promising, insufficient to guide treatment.

I use several of these frameworks in practice because they generate useful functional hypotheses. But we should present them as clinical frameworks rather than established diagnoses, and we should measure what we do: reading duration, community tolerance, return-to-work hours, not just clinical values on a chart.

Closing that gap is the work in front of us. I am currently working on a study with Michigan State University Sports Medicine and Dr. Andrea Lirones, O.D. F.A.A.O., examining yoked prisms paired with vision therapy following TBI.

Anchor every goal to occupation

The goal is not an improved near point of convergence. The goal is reading a bedtime story without a headache. Driving to an appointment. Getting through a shift. Remediation is a long process, but progress is real, and it is worth the referral.

Kara Christy, MS, OTRL, CBIS, is an occupational therapist with over 16 years of experience specializing in vision therapy, cognitive-perceptual motor retraining, and pre-driving rehabilitation. She is currently a Clinic Supervisor at Origami Rehabilitation in Lansing, Michigan.

Disclosure: The author is an investigator on the yoked prism study referenced above, which is not yet published.

Selected references

Ciuffreda KJ, Kapoor N, Rutner D, et al. Occurrence of oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry. 2007;78(4):155-161.

Merezhinskaya N, Mallia RK, Park D, et al. Visual deficits and dysfunctions associated with traumatic brain injury: a systematic review and meta-analysis. Optom Vis Sci. 2019;96(8):542-555.

Master CL, Scheiman M, Gallaway M, et al. Vision diagnoses are common after concussion in adolescents. Clin Pediatr (Phila). 2016;55(3):260-267.

Convergence Insufficiency Treatment Trial Study Group. Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol. 2008;126(10):1336-1349.

Subramanian PS, Barton JJS, Ranalli P, et al. Consensus statement on visual rehabilitation in mild traumatic brain injury. Neurol Clin Pract. 2022;12(6):422-428.

Biscardi M, Grossinger Z, Colantonio A, et al. Efficacy of restitutive interventions for oculomotor deficits in adults with mild traumatic brain injury: a systematic review and meta-analysis. Brain Inj. 2024;38(7):499-513.