Aim: To determine in vivo whether the LGN undergoes atrophy in patients with glaucoma and vision loss compared to normal subjects.
Methods: Following institutional St. Michael’s Hospital Research Ethics Board approval, a prospective and masked neuroimaging study was conducted on glaucoma patients with visual field defects affecting both eyes (n=10) and age-matched controls (n=8). Following informed consent, all subjects underwent 1.5 Tesla magnetic resonance imaging (MRI). Coronal proton density magnetic resonance images of both LGNs were obtained and LGN height measurements were measured by consensus by 3 neuroradiologists masked to the diagnosis. Glaucoma and control groups were compared using t-test.
Results: Both LGNs were identified and visualized by 1.5 Tesla MRI for every subject. Compared to controls, mean LGN heights in glaucoma were decreased in right (4.09 ± 0.89 mm vs. 4.74 ± 0.54 mm, p >0.05) and left LGNs (3.98 ± 0.57 mm vs. 4.83 ± 0.95 mm; p = 0.033). Combined right and left LGN height in glaucoma was significantly decreased compared to controls (8.07 ± 1.06 mm vs. 9.56 ± 0.86 mm; p = 0.005).
Conclusion: In vivo MRI evidence of LGN degeneration in human glaucoma is consistent with ex vivo primate and human neuropathological studies. LGN atrophy may be a relevant biomarker of visual system injury and/or progression in some glaucoma patients.
Abbreviations: LGN (lateral geniculate nucleus), RGC (retinal ganglion cell), MRI (magnetic resonance imaging)