Abstract
Purpose:
Retrograde trans-synaptic degeneration of retinal ganglion cell (RGC) neurons of the visual pathway has been demonstrated after various types of injury in humans and monkeys. In humans, this phenomenon can be seen in some but not all patients after stroke when imaging the peripapillary retinal nerve fibre layer with optical coherence tomography (OCT). We set out to test the hypothesis that owing to the anatomy of the visual pathway and refinements in OCT techniques the macula is a better region to demonstrate this finding. Additionally, we explored a potential correlation between sectorial thinning of RGC layer and the sensitivity loss of the corresponding quadrantic visual field (VF) defect.
Methods:
Retrospective case note review of patients with retrogeniculate lesions studied by OCT of the macula and automated VF analysis. Patients underwent imaging using the Zeiss Cirrus-HD OCT with the macular cube and peripapillary disc protocols. VFs were tested using the Humphrey analyser with the SITA-standard 24-2 protocol. Pattern standard deviations were calculated for each quadrant and correlated with the corresponding macula and peripapillary sector on the OCT images. Correlation coefficients were calculated with the Pearson product moment method. Significance level was set at 0.05.
Results:
8 patients with either hemianopia or quadrantanopia due to brain lesions (stroke =5; surgery = 2; CNS infection =1) were analyzed. A strong correlation was found between the pattern standard deviation of the VF quadrant and the corresponding macular RGC sector for the right (R =0.792, p <0.001) and left eyes (R =0.674, p <0.001).
Conclusions:
The correlation between sectorial thinning of the macular RGC and the depth of the VF defect in patients with posterior visual pathway lesions confirms that retrograde trans-synaptic neuronal degeneration occurs after visual pathway injuries even in small lesions. There is a significant functional correlate with the VF loss. This finding may have clinical applications analysing VF defects anatomically as well as an imaging marker for evaluating new neuroprotective therapies.
Keywords: 759 visual impairment: neuro-ophthalmological disease •
531 ganglion cells •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)