Macular ganglion cell–inner plexiform layer thinning in patients with visual field defect that respects the vertical meridian

Abstract

Abstract-Background:To compare the thinning patterns of the ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) as measured using Cirrus high-definition optical coherence tomography (HD-OCT) in patients with visual field (VF) defects that respect the vertical meridian.Methods: Twenty eyes of eleven patients with VF defects that respect the vertical meridian were enrolled retrospectively. The thicknesses of the macular GCIPL and pRNFL were measured using Cirrus HD-OCT. The 5% and 1% thinning area index (TAI) was calculated as the proportion of abnormally thin sectors at the 5% and 1% probability level within the area corresponding to the affected VF. The 5% and 1% TAI were compared between the GCIPL and pRNFL measurements.Results: The color-coded GCIPL deviation map showed a characteristic vertical thinning pattern of the GCIPL, which is also seen in the VF of patients with brain lesions. The 5% and 1% TAI were significantly higher in the GCIPL measurements than in the pRNFL measurements (all P < 0.01).Conclusions: Macular GCIPL analysis clearly visualized a characteristic topographic pattern of retinal ganglion cell (RGC) loss in patients with VF defects that respect the vertical meridian, unlike pRNFL measurements. Macular GCIPL measurements provide more valuable information than pRNFL measurements for detecting the loss of RGCs in patients with retrograde degeneration of the optic nerve fibers.

Long distance retrograde degeneration of the retino-geniculo-cortical pathway in homonymous hemianopia

“…We observed that the averaged GCC, crossed GCC, and non-crossed GCC were similarly effective in examining retrograde degeneration. This is consistent with prior reports in the literature of patients with visual pathway lesions [33, 34, 37]. Comparison of timing of thinning of RNFL and GCC has also been studied in optic neuropathy patients, and GCC thinning has been reported earlier than RNFL thinning in disease processes like retrobulbar optic neuritis, papilledema, and anterior ischemic optic neuropathy [38, 39].…”

“…A study by Herro et al of 9 patients between 3-14 months after occipital stroke reported 5.3 µm of GCC thinning between affected and unaffected hemi-retinas [33]. In general, as we discussed earlier, the decreased severity of RNFL thinning in comparison to severity of GCC thinning provides further evidence that GCC is superior to RNFL for studying retrograde degeneration of the visual pathway [33, 37].…”

Occipital tip injury with homonymous central scotoma: OCT-NFL and RGC correlation

“…This is intuitive, as half of all RGCs exist within the fovea and are responsible for central vision. Like Herro et al and Shin et al, we also found there to be significant GCL thinning in the absence of any RNFL atrophy, again confirming that GCL is a more specific measure of inner retinal thinning from retrograde neuronal degeneration 4 , 7 …”

“…GCL + IPL has been established as a sensitive marker of retinal thinning from acquired damage to the posterior visual pathways 3, 4, 5, 6, 7, 8, 9, 10. This is intuitive, as half of all RGCs exist within the fovea and are responsible for central vision.…”

“…Several distributions of retinal thinning have been described corresponding with homonymous hemianopia or homonymous quadrantanopsia1, 2, 3, 4, 5, 6, 7, 8 , 10 ; however, to our knowledge fewer studies have examined the relatively rare case of isolated macular-involving scotoma from injury to the occipital tip 9 . We describe this pattern of RNFL and retinal ganglion cell (RGC) complex loss from retrograde trans-synaptic neuronal degeneration.…”