Retinothalamic white matter abnormalities in amblyopia

Brian Allen, Melanie A. Schmitt, Burton J. Kushner, Bas Rokers

Research output: Contribution to journalArticlepeer-review

Abstract

PURPOSE. Amblyopia is associated with a broad array of perceptual and neural abnormalities in the visual system, particularly in untreated or unsuccessfully treated populations. Traditionally, it has been believed that the neural abnormalities are confined to the visual cortex and subcortex (e.g., lateral geniculate nucleus). Here, we investigate the presence of neuroanatomical abnormalities earlier in the visual stream, in the optic nerves and tracts, of participants with two predominant forms of amblyopia. METHODS. We used diffusion magnetic resonance imaging and probabilistic tractography to compare the microstructural properties of five white matter visual pathways between 15 participants with amblyopia (eight anisometropic, five strabismic, and two exhibiting both etiologies), and 13 age-matched controls. RESULTS. Participants with amblyopia exhibited significantly smaller mean fractional anisotropy in the optic nerve and optic tract (0.26 and 0.31 vs. 0.31 and 0.36 in controls, respectively). We also found greater mean diffusivity in the optic radiation compared to controls (0.72 µm2/s vs. 0.68 µm2/s, respectively). Comparing etiologies, the abnormalities in the precortical pathways tended to be more severe in participants with anisometropic compared to strabismic amblyopia, and anisometropic participants’ optic nerves, optic tracts, and optic radiations significantly differed from control participants’ (all, P < 0.05). CONCLUSIONS. The results indicate that amblyopia may be associated with microstructural abnormalities in neural networks as early as the retina, and these abnormalities may differ between amblyopic etiologies.

Original languageEnglish (US)
Pages (from-to)921-929
Number of pages9
JournalInvestigative Ophthalmology and Visual Science
Volume59
Issue number2
DOIs
StatePublished - Feb 2018

Keywords

  • Amblyopia
  • Diffusion MRI
  • Optic nerve
  • White matter

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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