Lesions in the Posterior Visual Pathway Promote Trans-Synaptic Degeneration of Retinal Ganglion Cells

Abstract

ObjectiveRetrograde trans-synaptic degeneration of retinal ganglion cell layer (GCL) has been proposed as one of the mechanisms contributing to permanent disability after visual pathway damage. We set out to test this mechanism taking advantage of the new methods for imaging the macula with high resolution by optical coherence tomography (OCT) in patients with lesions in the posterior visual pathway. Additionally, we explored the association between thinning of GCL as an imaging marker of visual impairment such as visual field defects.MethodsRetrospective case note review of patients with retrogeniculate lesions studied by spectral domain OCT of the macula and quadrant pattern deviation (PD) of the visual fields.ResultsWe analysed 8 patients with either hemianopia or quadrantanopia due to brain lesions (stroke = 5; surgery = 2; infection = 1). We found significant thinning of the GCL in the projecting sector of the retina mapping to the brain lesion. Second, we found strong correlation between the PD of the visual field quadrant and the corresponding macular GCL sector for the right (R = 0.792, p<0.001) and left eyes (R = 0.674, p<0.001).ConclusionsThe mapping between lesions in the posterior visual pathway and their projection in the macula GCL sector corroborates retrograde trans-synaptic neuronal degeneration after brain injury as a mechanism of damage with functional consequences. This finding supports the use of GCL thickness as an imaging marker of trans-synaptic degeneration in the visual pathway after brain lesions.

Changes in macular layers in the early course of non-arteritic ischaemic optic neuropathy

“…The correlation between the GCIP thinning and the VF defect may indeed be even stronger, as the GCIP thickness in eyes in which the VF was unobtainable due to poor visual function is significantly lower than the mean for the group. While point-to-point topographical correlation between the macular structures and the VF is not entirely established, the area represented by the scan is thought to represent 15°to 20°of the visual field [19]. Interestingly, the fact that we did not find a correlation between VF impairment and the GCIP thickness at baseline suggests that while significant damage occurs early in the course of AION, some structural changes are not fully established until after 1 month.…”

Alzheimer’s disease: A review of its visual system neuropathology. Optical coherence tomography—a potential role as a study tool in vivo

“…Evidence from OCT studies also supports a role for TRD in disorders of the posterior visual pathway [34,35,67,68] with visual field defects in these disorders correlating best with macular GCL thickness than with RNFL thickness [67,68]. Likewise, OCT findings in AD suggest the contribution of TRD in the pathophysiology of visual changes.…”

Macular Ganglion Cell Layer and Peripapillary Retinal Nerve Fibre Layer Thickness in Patients with Unilateral Posterior Cerebral Artery Ischaemic Lesion: An Optical Coherence Tomography Study

“…In a subsequent study by this group, 5 there was a detectable thinning of RNFL after 100 days of the insult, with greater loss occurring in the first 1-2 years. Only case reports 3,24 and small-sample studies [25][26][27] have reported a thinning of the RGC layer in the hemiretina of patients with either mixed posterior lesions or isolated PCA ischaemic events. To our knowledge, this is the first case-control study with patients with unilateral PCA ischaemic lesions.…”