Abstract
Purpose: :
To identify the causes of isolated infantile nystagmus in children referred to a tertiary care pediatric ophthalmology practice.
Methods: :
Retrospective chart review. Subjects were referrals to the pediatric ophthalmology service from 1993 to 2010 with an ICD-9 code for congenital nystagmus. Inclusion criteria and definition of isolated infantile nystagmus are onset of nystagmus less than 6 months of age and no accompanying neurologic or systemic abnormalities. Diagnosis was made on the basis of complete eye exam, family history, electroretinogram (ERG), optical coherence tomography (OCT), molecular genetic testing, and MRI.
Results: :
88/316 patients with infantile nystagmus met inclusion criteria. 52 were male and 36 female. All had normal birth histories and follow up averaged 7.7 years. 15/88 had a family history of nystagmus or ocular disease. 35 underwent brain imaging. 7/35 were abnormal. All 7 were ordered to rule out midline defects based on a clinical diagnosis of optic nerve hypoplasia. Macular OCT was performed in 6 patients and 2 had foveal hypoplasia. 18 ERGs were performed. 9/18 were abnormal. Molecular testing was performed on 14 and 8 had mutations in genes known to cause retinal degeneration. Nystagmus etiology: 44 presumed congenital motor nystagmus, 5 X linked motor nystagmus, and 39 sensory nystagmus (17 albinism, 8 optic nerve hypoplasia, 3 cone dystrophy, 3 LCA, 2 macular dragging secondary to ROP, 2 retinal coloboma, 1 congenital cataracts, 1 retinitis pigmentosa, 1 CSNB, and 1 optic nerve atrophy). 35/49 patients with presumed motor nystagmus had optotype vision recorded at their last visit and the average acuity was 20/37. By comparison, 34/39 of those with sensory nystagmus had an average acuity of 20/220 (p=0.0003).
Conclusions: :
44% of patients with isolated infantile nystagmus, who presented to our tertiary care pediatric ophthalmology practice, have an ocular disorder that causes sensory nystagmus. A complete ocular examination is essential to distinguish between motor and sensory nystagmus. The majority of patients with presumed motor nystagmus have good vision. Testing should be ordered based on physical and ocular findings.
Keywords: nystagmus • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal degenerations: hereditary