Identification of binocular vision dysfunction (vertical heterophoria) in traumatic brain injury patients and effects of individualized prismatic spectacle lenses in the treatment of postconcussive symptoms: a retrospective analysis.

OBJECTIVE To identify a form of binocular vision dysfunction (vertical heterophoria) in a traumatic brain injury (TBI) population and to assess the effect of individualized prismatic spectacle lenses on postconcussive symptoms. DESIGN Retrospective study. SETTING Private physical medicine and rehabilitation practice and private optometric practice. PATIENTS A subset of TBI patients who were initially evaluated by a single physiatrist and who received standard treatments and medications yet had persistent postconcussive symptoms. These patients were then assessed by a single optometrist, and those found to have vertical heterophoria were treated with individualized prismatic spectacle lenses. A total of 83 patients were referred for testing; 77 were positive for vertical heterophoria on screening, of which 43 had complete data sets and were included for analysis. INTERVENTIONS All patients were treated with individualized prismatic spectacle lenses to correct for vertical heterophoria. MAIN OUTCOME MEASURES Outcomes were measured by the difference in score before and after intervention of an objective, self-administered vertical heterophoria symptom burden instrument (Vertical Heterophoria Symptom Questionnaire [VHS-Q], presently undergoing validation) and by subjective improvement in symptoms as expressed by the patient at the end of intervention. RESULTS There was a 71.8% decrease in subjective symptom burden when compared with preintervention baseline. There was a mean 16.7 point absolute reduction in the VHS-Q score on a 75-point scale, which represents a relative reduction in VHS-Q score of 48.1%. CONCLUSION Vertical heterophoria was identified in a group of TBI patients with postconcussive symptoms and treatment of the vertical heterophoria with individualized prismatic spectacle lenses resulted in a 71.8% decrease in subjective symptom burden and a relative reduction in VHS-Q score of 48.1%. It appears that vertical heterophoria can be acquired from TBI.