Patients with chronic symptoms following concussions have difficulty in particular measures of vergence, accommodation and visual tracking, and these symptoms may be more complex than previously reported, researchers found in a study published in Vision Research.

“This [more extensive] breadth indicates that aggregate diagnoses such as [convergence insufficiency], accommodative insufficiency, and saccadic dysfunction are inadequate in explaining the persistent symptomatology in the 1.1–1.9 million concussions occurring annually in adolescents,” investigators report. “Instead, these findings indicate that the approach to post-concussion visual symptoms should include evaluation of individual details in the vergence, accommodative, and visual tracking measures, and these details may be leveraged to personalize treatment for each symptomatic patient.”

The researchers reviewed the medical history of patients (5 to 21 years old) at Boston Children’s Hospital’s Multidisciplinary Concussion Clinic who had presented with postconcussion symptoms that lasted at least 21 days and had visual acuity of at least 20/30 in each eye. They excluded patients with amblyopia, manifest strabismus, vision therapy, malingering or conversion syndrome diagnosis, or ocular pathology diagnosis that impacted visual function.


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They assessed the ocular alignment, motility, vergence, accommodation and tracking of 116 patients (median age 15.7 years) 21 to 1192 days after the most recent concussion. 56 patients had sustained more than 1 concussion. Most concussions were caused during sports (n=58).

Thirty percent of patients had ocular misalignment (28 with exophoria, 10 with esophoria). Seventy patients had receded near point convergence (NPC), and patients with exophoria had more receded NPC compared with patients with orthophoria (P =.005, mean difference 3.1 cm) while patients with esophoria had higher positive fusional vergence. Receded NPC significantly correlated with decreased PFV (P <.001, r=-0.35).

Less accommodation was the most common accommodative ocular behavior, found in 54.3% of patients. Most patients who failed accommodative facility testing had relaxing accommodation.

Nearly all (n=106) patients had vergence and accommodative deficits. Decreased accommodative amplitude was linked with receded NPC and decreased PFV at near (r=-0.57, r=0.36, respectively, P <.001).

NPC and accommodative amplitude correlated with vertical developmental eye movement performance but not horizontal developmental eye movement performance.

There was some correlation with refractive error and accommodative facility (r=-0.25, P =.01) and accuracy (r=0.21, P =.03) in the right eye spherical equivalent, with hyperopic patients having lower cycles per minute and lag accommodation, the researchers report.

Limitations of the study included risk of population bias and lack of consideration of pupil dynamics.

Disclosure: One study author declared affiliations with biotech, pharmaceutical and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Wiecek EK, Roberts TL, Shah AS, Raghuram A. Vergence, accommodation, and visual tracking in children and adolescents evaluated in a multidisciplinary concussion clinic. Vision Research. 2021;184:30-36. doi:10.1016/j.visres.2021.03.002

This article originally appeared on Optometry Advisor