Davis, Kristin1; Dumitrescu, Alina1; Vandelune, Joel1; Peotta-Jacobsen, Veronica1
1Department of Ophthalmology and Visual Sciences, University of Iowa
Purpose: Nystagmus is uncontrolled, repetitive movements of the eyes. Nystagmus is a clinical symptom associated with a multitude of diseases ranging from neurological causes, such as periventricular leukomalacia or congenital malformations of the brain, to ophthalmic etiologies such as albinism, retinal diseases with onset in childhood, to benign causes. Nystagmus can be clinically described based on its amplitude, frequency, direction of oscillations, and variation with the gaze direction. The diagnostic workup to identify the cause of nystagmus is inclusive and targeted simultaneously, including imaging, electrophysiology, and genetic testing. Despite extensive work done to classify nystagmus, an objective method has yet to be. This study aims to evaluate eye movement recordings' role in the correct and complete diagnosis of patients with nystagmus.
Methods: Patients with nystagmus evaluated in the pediatric ophthalmology and pediatric inherited eye disorder clinics at the University of Iowa were prospectively enrolled in this study. In addition to their regular workup, patients underwent video recording of their nystagmus using the Neurolign Dx 100. This device is an FDA-cleared eye-tracking device previously used for other eye conditions and is currently under investigational use for recording nystagmus. It consists of VR-style goggles worn by the patient. Horizontally and vertically moving targets are displayed, while multiple infrared cameras record the eye movements and oscillations. This painless, noninvasive procedure does not require anesthesia and roughly takes 10 minutes. The recordings are then analyzed to measure nystagmus direction, frequency, amplitude, intensity, and waveform morphology. The nystagmus characteristics will then be compared with the etiology as determined by the clinical workup for correlation.
Results: Thus far, our study has enrolled 40 patients: 22 males and 18 females between the ages of 4 and 18. Nystagmus recordings were successfully obtained from all patients. Ten individual waveform morphology patterns were identified. The classification and waveform morphology analysis obtained using automatic eye- tracking recordings was more detailed and reproducible than the clinical description. Four different categories of underlying nystagmus etiology were identified. Of those enrolled, 45% had oculocutaneous albinism, 22.5% had optic nerve anomalies, 20% had retinal dystrophies, and 12.5% had congenital motor nystagmus. Visual acuity was grouped into 3 categories: good (20/40 or better), moderately decreased (20/40 to 20/100), and poor (worse than 20/100). The underlying etiology correlated with the severity of visual acuity. However, no correlation between the nystagmus waveform morphology or pattern and the underlying diagnosis or visual acuity has been established thus far.
Conclusions: So far in this study, we demonstrated that automated nystagmus recording and classification is possible and reliable. This is an ongoing study, and a larger number of recordings are required before drawing the final conclusions on these recordings' clinical applicability and usefulness.
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