advertisement
Zhang et al. present data based on magnetic resonance image (MRI), diffusion tensor MRI and optic coherence tomography (OCT) on optic-nerve and chiasm volume in 30 normals and 30 patients with normal-tension glaucoma. The study confirms a correlation between decreased optic chiasm height, optic nerve volume as well as a reduced optic nerve diameter, reduced lateral geniculate (LG) volume and a reduced retinal nerve fiber thickness. The loss of volume in the LG is thought to reflect the intracranial involvement of glaucoma, thus making normal-tension glaucoma a disease of the central nervous system.
The loss of volume in the LG is thought to reflect the intracranial involvement of glaucoma, thus making normal-tension glaucoma a disease of the central nervous system
The study however does not approach the question where the pathology initiated, e.g., the retinal ganglion cells, the axons itself or the LG. The findings of this paper are in line with previous work in the same field, but based on a different population. For comparative studies the genetic background in the present study raises some important questions. Normal-tension glaucoma is a subgroup of open-angle glaucoma in the western hemisphere, but makes up the far largest group of open-angle glaucoma in Japan. This raises the question whether anatomical differences in these two populations might exist that need to be considered when different ethnic groups are involved. Such a difference for example was found in the diameter of the subarachnoid space in Asians and Europeans. Further studies are definitely necessary to address this problem.