Pre- and Postnatal Damage to the Retro-Geniculate Visual Pathways Cause Retinal Degeneration Predictive for Visual Function

Abstract

To increase the understanding of the relationship between structure and function in individuals with damage to the brain from different stages of maturation of the visual system, we examined 16 teenagers and young adults. We used diffusion-weighted magnetic resonance imaging (MRI) and fiber tractography of the optic radiation (OR) and optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (pRNFL) and the ganglion cell layer + inner plexiform layer (GC+IPL) in the macula. Visual field (VF) function was assessed with the Humphrey Field Analyzer (HFA). Injuries to the immature OR were associated with thinning of the pRNFL and GC+IPL, and corresponding VF defects irrespectively of timing of the lesion. However, in cases with bilateral white-matter damage of immaturity (WMDI) we noticed a well preserved central VF despite a very thin GC+IPL. We speculate that this is due to plasticity in the immature visual system. Similar results were not noticed among cases with unilateral damage, acquired pre- or postnatally, in which the central VF was affected in most cases. OCT has proved to be a valuable targeted tool in children with damage to the retro-geniculate visual pathways, and that focal thinning of the GC+IPL predicts VF defects. This brief research report includes a review of four previously published papers. In addition, we present one new case and apply a recently developed classification system for CVI. The classification was applied on cases with bilateral WMDI to investigate its relation to retinal structure.

The Multidisciplinary Guidelines for Diagnosis and Referral in Cerebral Visual Impairment

“…In children with CVI optic nerve parameters (OCT, HRT) differ from typically developing children (optic disk surface, cup/disk ratio). (Ruberto et al, 2006) With OCT retrograde transsynnaptic (RTSD) degeneration can be detected (Lennartsson et al, 2021) The ganglion cell thinning corresponded with the visual field defects and the extent and location of the primary brain damage. The most important sign of RTSD was asymmetry of the ganglion cell topography within the macular area (Jacobson et al, 2019).…”

Case report: Bilateral damage to the immature optic radiation and secondary massive loss of retinal ganglion cells causing tunnel vision

“…VF-deficits in children with WMDI have been described as unilateral or bilateral homonymous defects most often affecting the inferior VFs ( Dutton et al, 2004 ; Jacobson et al, 2006 ). In individuals with bilateral WMDI, we have noticed relative sparing of the very central VF, possibly due to the plasticity of the immature visual system ( Lennartsson et al, 2021 ). This case illustrates that visual input may be severely restricted by bilateral damage of the optic radiation with RTSD of a majority of the retinal GCs, and yet there is measurable, but subnormal VA in combination with tunnel vision.…”