To the Editor:
We thank A Pircher and HE Killer for their response to our article and their significant contribution to this field [1].
We suggested that the optic nerve compartment syndrome in HE Killer’s patient may have altered the makeup of the cerebrospinal fluid (CSF) surrounding their optic nerve, giving it a higher concentration of interstitial fluid than CSF from lumbar puncture [2].
Patients with normal tension glaucoma (NTG) could indeed have different compartmentation of their optic nerves, or a different makeup of the CSF surrounding their nerves compared with normal patients.
Pircher et al.’s observational study was mentioned in our review, but as there was no control group the authors were unable to compare intracranial pressure (ICP) in NTG patients to ICP in normal subjects [3]. Furthermore, the patients were all those in whom CSF compartment syndrome was suspected, which may have biased results.
We mention the study by Linden et al., but point out significant flaws in the study design: it was likely underpowered, and 51 controls were used from a separate study. They may not have been comparable with the 13 NTG patients examined [4].
Glaucoma in mice is not identical to that observed in humans. Despite mice not having a lamina cribrosa, we believe the lamina cribrosa plays a role in glaucoma in humans.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Footnotes
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References
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