A normal pressure reading is a good sign but in some cases does not rule out glaucoma. There is a type of glaucoma which goes by the name of Low-tension glaucoma which is a sub-variety of open angle glaucomas in which you see optic nerve damage and also visual field loss at the time that intraocular pressure is at normal levels. Also known as normal tension glaucoma or low pressure glaucoma.
This type of glaucoma with normal eye pressure usually develops slowly. The National Eye Institute reports that glaucoma which occurs in the presence of normal eye pressure is a thing and also that reducing pressure in the eye may still be helpful in slowing the disease.
What Is Low-Tension Glaucoma?
This type of glaucoma with normal eye pressure usually develops slowly. The National Eye Institute reports that glaucoma which occurs in the presence of normal eye pressure is a thing and also that reducing pressure in the eye may still be helpful in slowing the disease.
The tolerance of pressure varies between individuals. Also some optic nerves may be more prone to pressure and blood flow changes. Low-tension glaucoma which is a diagnosis of a complete clinical picture rather than a single tonometer reading.
| Feature | Typical Open-Angle Glaucoma | Normal-Pressure Form |
| Eye pressure | Often elevated | Usually within normal range |
| Optic nerve damage | Present | Present |
| Visual-field loss | Usually gradual | Usually gradual |
| Treatment goal | Lower pressure | Lower pressure further and monitor |
Low-Tension Glaucoma Causes and Risk Factors
The exact normal tension glaucoma causes is still not fully known. In case of Low-tension glaucoma we see a multi factor cause. NCBI reports associations with family history, thin central corneas, low night time blood pressure, migraine, Raynaud phenomenon and obstructive sleep apnoea.
The exact cause of normal tension glaucoma is still not fully known. In case of low tension glaucoma we see a multi factor cause. NCBI reports associations with family history, thin central corneas, low night time blood pressure, migraine, Raynaud phenomenon and obstructive sleep apnoea.
Normal Tension Glaucoma Symptoms
Early in the course of normal tension glaucoma symptoms may be absent. As low-tension glaucoma progresses a person may develop over time blind spots or loss of peripheral vision. Some defects may appear closer to central vision.
Because there is a risk that normal eye pressure vision loss may occur with normal eye pressure, we advise regular eye care which is very important for people with a family history of glaucoma or which has reports of unusual activity in the optic nerve.
How Is Low-Tension Glaucoma Diagnosed?
A diagnosis of low-tension glaucoma does not present itself from a single pressure reading. The ophthalmologist will repeat pressure measures and look at the optic nerve, visual field and corneal thickness. Also in the works are tests to rule out other conditions which may look like glaucoma.
| Test | Purpose |
| Tonometry | Measures eye pressure |
| Dilated optic nerve examination | Checks for optic nerve damage |
| OCT | Measures retinal nerve-fibre and ganglion-cell layers |
| Visual-field test | Detects reduced or missing areas of vision |
| Pachymetry | Measures corneal thickness |
| Gonioscopy | Confirms the drainage angle is open |
These tests help to identify normal eye pressure glaucoma from other causes of optic nerve damage.
Low-Tension Glaucoma Treatment
The goal of low-tension glaucoma treatment is to prevent progression of optic nerve damage. In some cases which present with intraocular pressure in the normal range we see that reduced pressure is still beneficial at a certain degree. Target pressure in these patients is very much related to how severe the disease is at the moment and also will change over time.
Treatment of low-tension glaucoma may include the use of prescription eye drops, selective laser trabeculoplasty or surgery as a last option. What is best for glaucoma treatment depends on pressure patterns, visual field damage and also the patient’s health.
Doctors also report very low night time blood pressure or sleep apnea. Blood pressure medications should always check in with the prescriber before making any changes.
Why Regular Monitoring Matters
Low-tension glaucoma is a chronic condition. What may appear to be stable intraocular pressure doesn’t always indicate the health of the optic nerve. We use follow up OCT scans, visual field tests and physical examination of the optic nerve to identify any disease progression.
At Vasan Eye Care patients that have suspected low-tension glaucoma may access a structured glaucoma evaluation and long term monitoring at an eye hospital. Consistent follow up may help preserve usable vision.
Conclusion
A normal pressure result is not an indicator of healthy optic nerves. Low-tension glaucoma is what notes we may overlook pressure in glaucoma diagnosis. If you are experiencing unexpected normal eye pressure vision loss,, have a family history of glaucoma, or have what appears to be unusual findings in the optic nerve see an eye specialist.
Frequently Asked Questions
1. Can you have glaucoma with normal eye pressure?
Yes. Glaucoma with normal eye pressure does occur and is known as low-tension glaucoma or normal tension glaucoma.
2. Can it be cured?
No. Existing optic nerve damage is usually a permanent issue but we can do something to prevent more damage.
3. Which tests help confirm the diagnosis?
Doctors typically do pressure measurement, OCT, optic nerve exam, visual field testing and pachymetry.
4. Can it cause blindness?
Yes. Advanced low-tension glaucoma is known to cause severe vision loss, but in which it can also be arrested at early stages and prevented from progressing.
References
- National Eye Institute — Types of Glaucoma
https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/glaucoma/types-glaucoma - NCBI Bookshelf — Normal Tension Glaucoma
https://www.ncbi.nlm.nih.gov/books/NBK576377/