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Subject Area

Cardiology and Vascular Medicine

Article Type

Original Study

Abstract

Objectives To evaluate the use of electroretinography (ERG) and recording of visual-evoked potentials (VEP) as diagnostic tools in children with early-onset nystagmus to clarify the need to include them as a basic step in the evaluation of cases of early-onset nystagmus, especially with normal ocular examination. Background Nystagmus in children can be caused by many causes, starting from idiopathic motor nystagmus compatible with relatively good vision, ending with ocular abnormalities that impair vision or other neurologic abnormalities that may be life threatening. Knowledge of the exact diagnosis is essential in the rehabilitation of a visually impaired child. Patients and methods In 32 children with early-onset nystagmus, ERG was recorded under light sedation, and VEP were simultaneously recorded to flash stimulus in all patients. Results The study comprised 64 eyes of 32 patients, with their age ranging from 3 months to 7 years. Indications for referral included children with early-onset nystagmus. Children with obvious cause for nystagmus were excluded from the study. Overall, 37.5% of children had been diagnosed as having retinal dysfunction, including cone dystrophy (6.3%) and cone/rod dystrophy (31.2%). Neurological nystagmus was recognized in 34.3% of children. Ocular albinism was diagnosed in 6.3% of cases. One (3.1%) case was diagnosed as optic nerve hypoplasia. Six (18.8%) cases were diagnosed as idiopathic nystagmus. Conclusion This study clarified the need to investigate children with nystagmus by ERG and suggested that the ERG was useful where the diagnosis was uncertain, particularly at an early age with no obvious cause on ocular examination. VEP are complementary to ERG and can be tested simultaneously. Visual electrophysiological examination of children with early-onset nystagmus can establish or exclude retinal and postretinal pathway dysfunction, thus assisting in its classification and subsequent rehabilitation.

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