Thank you for that extra information.
The pressures you have reported are well within the "normal" range of 10 to 21 mmHg. That being said, if your ophthalmologist is finding evidence of nerve damage and visual field changes consistent with the diagnosis of glaucoma, or "glaucoma suspect" then you may be suffering from a disease called "low tension glaucoma"
In the most common form of glaucoma (primary open angle glaucoma) the intraocular
pressure is elevated above normal. In some cases the eye pressure is never found to be above 21mmHg even though there is clear cut evidence of glaucomatous damage.
Unfortunately, the only way we know how to treat glaucoma -- even low tension glaucoma -- is to lower the eye pressure. As you might imagine it can be very difficult to get the eye pressure low enough to stop the progression of disease if the pressure is already "low/normal"
I am glad to hear that your repeat testing has showed no further evidence of disease. With your diagnosis, I can not stress enough the importance of careful followup with your ophthalmologist as this is a silent and blinding disease.
Should you have any concerns it might be useful for you to obtain a second opinion from a glaucoma specialist.
To answer your question directly: Yes, there are other causes of optic nerve damage but it would be unlikely that your ophthalmologist would not rule them out before diagnosing you with low tension glaucoma or glaucoma suspect. Also, the morphology of optic nerve damage and visual field changes found in other forms of optic nerve disease are usually very different.
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