Characteristics of Infantile Nystagmus using Hand-Held Ultra-High Resolution Spectral Domain Optical Coherence Tomography in Infants and Small Children

Abstract

Purpose: To investigate the feasibility and clinical use of ultra-high resolution spectral domain hand-held OCT (HH-OCT) in a systematic study of pathological foveal development in a cohort of infants and young children with nystagmus.

Methods: 50 patients were recruited and compared to 50 age-matched controls. The mean age was 3.2 ± 2.0 years (range 0-8 years). Each patient had a full orthoptic and ophthalmological examination, and a HH-OCT scan (Bioptigen, 2.6µm axial resolution) without sedation. Each scan was screened for the presence of foveal hypoplasia (graded from 0-4) or atypical foveal hypoplasia and other abnormalities of macular morphology. A differential diagnosis was made on the basis of OCT findings and correlated with, clinical, genetic or electrophysiological findings.

Results: Scans were obtained in 94% of cases at the first examination and 100% at the second examination. Twenty-three patients had typical foveal hypoplasia. Of these, 21 had albinism and 2 harboured PAX6 mutations. Five patients had atypical foveal hypoplasia (continuous inner retinal layers in the macula region with additional evidence of inner segment/outer segment junction disruption). Six cases with retinal dystrophy had other abnormal macular morphology. The remaining 16 patients had a normal examination, with 12 subsequently diagnosed with idiopathic nystagmus and 4 with latent nystagmus.

Conclusions: Excellent feasibility of the HH-OCT in this challenging cohort of infants and young children with nystagmus has been demonstrated. Examining OCT scans for the presence or absence of foveal hypoplasia, whether it is typical or atypical, and the presence or absence of other abnormal macular morphology, is helpful in the differential diagnosis of infantile nystagmus. This may facilitate more focused investigations and earlier diagnosis, which is likely to become increasingly important in an era where potentially time sensitive interventions such as gene therapy are being undertaken.

Keywords: 619 nystagmus • 550 imaging/image analysis: clinical • 556 infant vision