Glaucoma is usually associated with high intraocular pressure, which causes damage to the optic nerve, which can result in permanent loss of vision. Normal-tension glaucoma is a rare condition in which the optic nerve damage and vision loss occur despite normal pressure within the eye.
Normal blood pressure in the eye ranges between 10 and 21 mm Hg, and most people with glaucoma have a blood pressure greater than 21 mm Hg. Unfortunately, in the case where there is normal-tension glaucoma, it shows an average pressure, which is often confusing.
The properties of glaucoma with normal intraocular pressure are similar to primary open angle glaucoma, and its incidence is more common in women than in men. It is also a type of glaucoma that occurs mainly in middle-aged people about 60 years old.
Causes of normal-tension glaucoma
Although the reasons for this type of glaucoma are not entirely understood, it usually appears as a result of an extremely brittle optic nerve that is damaged despite normal pressure within the eye or due to the reduction of blood flow to the optic nerve.
Normal-tension glaucoma can be the inherited disease, and the limited blood flow to the optic nerve may also result from disorders of the blood vessels (vascular diseases), including vascular contractions and ischemia.
Symptoms of normal-tension glaucoma
Regular eye examinations are imperative, because people suffering from this insidious type of glaucoma, often have no awareness of the disease to the time when it is in a highly advanced stage. The right pressure inside the eye that makes glaucoma with normal intraocular pressure shows no early symptoms and damage to the optic nerve causing permanent, irreversible damage and even blindness.
Because the disease does not show any specific symptoms, the following are important:
- regular studies to monitor nerve damage and vision loss,
- paying particular attention to the eyes in case of cardiovascular diseases and neurological disorders, as these are health problems that increase the risk of this type of glaucoma,
- special consideration for research family history of diseases which take into account this kind of glaucoma.
- the problems of eye conditions,
- migraine headaches,
- the injuries of eyes, head or ears,
- the use of drugs – mainly steroids,
- the diseases such as Raynaud’s syndrome,
- problems with blood clotting,
- significant blood loss or shock,
- night hypotension,
- autoimmune disorders,
- cardiovascular diseases, including atherosclerosis,
- thyroid disease,
- sleep apnea,
- Alzheimer’s disease.
Diagnosis of normal-tension glaucoma consists of measuring the pressure inside the eye, examination of the whole eye using specialized equipment and analysis of symptoms and family history of the diseases. Suspension of normal-tension glaucoma often requires multiple daily tests (so-called daily assessment) to rule out other conditions.
Treatment usually involves the use of medication and adherence to medical advice, but when the patient’s condition worsens, surgery or laser surgery may be necessary. Glaucoma with normal intraocular pressure requires ophthalmic control to monitor the progression of the disease.
Unfortunately, there is no proven method to prevent glaucoma. Therefore the only and the best prevention is regular ophthalmic visit and early diagnosis, which allows making a rapid reaction, preventing further damage to the optic nerve and loss of vision.