Barry Tannen

Relation between distance heterophoria and tonic vergence

ABSTRACT The distance heterophoria was measured using both the von Graefe and Maddox rod clinic procedures under standard reduced illumination conditions and in total darkness. Tonic vergence was measured in total darkness. The phoria measures were more divergent than tonic vergence, with the von Graefe being the more divergent of the two measures. The difference between the phoria and tonic vergence position is believed to be due to accommodative divergence derived from the decrease of accommodation, relative to the tonic level, required to focus the distance phoria target. Equations were derived to predict tonic vergence from the phoria value.

Orthoptic treatment and eye movement recordings in Guillain-Barré syndrome: A case report

A 50-year-old patient with Guillain-Barre syndrome developed a symmetrical, bilateral sixth nerve palsy which resulted in constant esotropia and diplopia. The patient was treated with both prisms and orthoptics, which eliminated the diplopia. This treatment also improved both fu-sional divergence amplitudes and vergence adaptation. Objective eye movement recordings revealed subtle abnormalities of fixation, pursuit and saccades, i.e., square-wave jerks and intermittent saccadic dysmetria.

Complex regional pain syndrome type I: associated visual sensorimotor case findings.

ObjectiveThe objective was to present new visual sensorimotor findings in a patient with complex regional pain syndrome type I, formerly known as reflex sympathetic dystrophy. DesignClinical measurements were compared for the following visual sensorimotor tasks before and after 10 minutes of near visual stimulation: accommodation, vergence, and reading eye movements. PatientThe patient was a 19-year-old female university student with complex regional pain syndrome type I. ResultsAll visual sensorimotor findings worsened dramatically after performance of the brief near visual task. In addition, the patient experienced severe dizziness, nausea, dull eye ache, and general fatigue, which persisted for 30 to 45 minutes following each test period. ConclusionsThe patient manifested signs and symptoms of complex regional pain syndrome type I per the prior neurologic diagnosis, as well as the newly diagnosed accommodative infacility, accommodative insufficiency, convergence insufficiency, and deficits of saccades and pursuits, which were severely debilitating. The findings neither support nor refute the conventional notion of abnormal sympathetic mediation as a mechanism of fatigue and pain. However, the diagnoses of accommodative infacility and insufficiency suggest abnormal parasympathetic activation. Further investigation is needed to characterize the array of visual dysfunctions in a large sample of such patients, which may help elucidate the precise underlying neurologic causes of the sensorimotor deficits in these patients.

Prevalence of esophoria in concussed patients

Purpose To assess the prevalence of esophoria at near in concussed patients in a neuro-optometric private practice setting. Methods A retrospective analysis was performed involving a chart review in a neuro-optometric, private practice setting of consecutive patients with a medical diagnosis of concussion from January 1st 2016 to December 31st 2016. A total of 71 patients were included in the analysis. All received a comprehensive vision examination, with a near vision emphasis. The near horizontal phoria was assessed with the cover test and the von Graefe test. Results Approximately 30% of the patients with a medically based diagnosis of concussion exhibited esophoria at near, with good agreement (95%) between the two tests. Mean esophoria was 5.2 (SD = 2.8) prism diopters (pd), with a range from 2pd to 14pd of esophoria. Convergence excess was diagnosed in 23%. Discussion Near esophoria was found in nearly one-third of this practice-based sample of concussed patients. Thus, it was more common than typically believed to be the case. Two proposed oculomotor-based mechanisms related to these symptomatic esophoric patients included phoria decompensation and excessive accommodative vergence.