Abstract
Purpose: :
To evaluate the utility of hand-held spectral-domain optical coherence tomography (SD OCT) imaging in the evaluation of pediatric patients with congenital nystagmus.
Methods: :
Patients referred to the Oregon Retinal Degeneration Center with a diagnosis of congenital nystagmus underwent sedated electroretinograms followed by imaging with a hand-held SD OCT device (Bioptigen). The position of the reference arm and the focus setting on the hand piece were adjusted for the patient’s age and refraction, respectively. Linear scans through the fovea and optic nerve (typical settings of 8.0 mm, 1000 a-scans/b-scan x 80 scans) as well as rectangular volume scans (typical settings of 7.0 mm x 7.0 mm, 750 a-scans/b-scan x 256 scans) were obtained in each eye. The data were converted to AVI files and then averaged off-line using ImageJ software. Segmentation and thickness measurements were made using custom software in Igor Pro.
Results: :
Seven patients, ages 15 months to 8 years, with congenital nystagmus were examined with SD OCT imaging. Based on clinical presentation and electrophysiology there were 2 patients with albinism, 2 patients with congenital idiopathic nystagmus, and 1 patient each with achromatopsia, blue cone monochromatism (BCM), and high myopia. Hand-held SD OCT imaging of the patients with albinism showed loss of the foveal pit evident on both line and volume scans. The patient with achromatopsia had normal retinal architecture including inner segment outer segment (IS/OS) junction but demonstrated subtle foveal granularity at the level of the OS. In the patient with BCM, there were persistent inner retinal layers as well as loss of the inflection of the IS/OS junction in the fovea. The patients with congenital idiopathic nystagmus and the patient with high myopia all had normal retinal architecture.
Conclusions: :
Hand-held SD OCT is useful in the evaluation of infants with congenital nystagmus, especially in the consideration of albinism where loss of the foveal pit was readily demonstrated. Achromatopsia and BCM hand-held SD OCT imaging showed essentially intact retinal architecture, including the IS/OS junction, suggesting the potential for visual preservation with future therapies.
Keywords: imaging/image analysis: clinical • retinal degenerations: hereditary • nystagmus