Sensorimotor Characteristics of Neuro-Ophthalmology and Oculo-Plastics Patients

Background and Purpose Certified orthoptists are routinely required, as a standard component of outpatient care, to examine and identify the cause of double vision described by neuro-ophthalmology and oculo-plastics patients. Peer-reviewed articles in the strabismus literature describing the significance of this role of the orthoptists, especially in more complex cases of strabismus, do exist, but are outdated. The importance of creating a differential diagnosis in the understanding of the disease process is a well-recognized component of medical education and modern medicine. Patients and Method This work was a retrospective chart review and descriptive study of the most common clinical characteristics of adult neuro-ophthalmology and oculo-plastics patients seen over a 9-year period by an orthoptist in a large, urban academic institution in the United States. History and clinical data obtained included demographic information; whether the subjects were neuro-ophthalmology or oculo-plastic patients or both; chief complaint; past medical history and associated medical risk factors; past ocular history of strabismus or amblyopia; whether reported diplopia was monocular or binocular; visual acuities; sensorimotor examination and fusion status information; presence or absence of ptosis; pupil size and reactivity; basic accommodative function; orthoptist and physician diagnoses; and suggested treatment of diplopia. Results Five hundred seventy-five subjects were identified based on inclusion criteria. Racial demographics matched that of the state of Maryland, with the majority of the patients being Caucasian. The minority were of Hispanic origin. Ninety-one percent of the study cohort was referred by the department of neuro-ophthalmology at the institution. Hypertension was a statistically significant medical risk factor for acquired strabismus and diplopia in this adult cohort. Etiology for the strabismus and associated diplopia suggested by the orthoptist was in close agreement with the final diagnosis made by the referring physician. Pupil-sparing oculomotor palsy (third cranial nerve, CN3) occurred as frequently as pupil-involving CN3, with tumor occurring more frequently as an etiology than aneurysm in both groups. Trochlear nerve palsy (CN4) was more often associated with hydrocephalus than abducens nerve palsy (CN6), and trauma remained a common association with acquired CN4 palsy. In patients with thyroid eye disease (TED), eso- and exo-deviations occurred with similar frequency. As has been reported in the literature, concomitant myasthenia gravis (MG) remained rare in these patients, although occurring with similar frequency in patients with both types of horizontal deviation. In patients with ptosis, asymmetry was not statistically more predictive of MG than symmetry. Prism was used most frequently, followed by surgery, to address diplopia symptoms. Lastly, there was a statistically significant association of acquired strabismus and diplopia in female subjects with breast cancer and no past ocular history of childhood strabismus or amblyopia. Conclusion The thorough assessment of sensorimotor function, fusion, and visual acuity provided by the orthoptist is an important clinical adjunct in developing the differential required to make an accurate final diagnosis, which sometimes may not subscribe to accepted clinical norms reported in the literature. The orthoptist also plays an important role in the nonsurgical treatment of acquired diplopia due to strabismus. Fresnel Press-OnTM or ground-in spectacle prism was a commonly used treatment for diplopia.