Definition of Glaucoma:
Glaucoma is a disease of the optic nerve, most often due to an increase in pressure in the eye (abnormal rise in intra-ocular pressure above 21 mm Hg), which requires treatment when it exceeds 30 mm Hg. It is manifested by a loss of visual field due to the destruction of optic fibers. Glaucoma can be congenital, due to an anatomical anomaly, or secondary to other ocular disorders affecting the iris or lens, or post-traumatic…
There are 2 types of glaucoma:
- open-angle glaucoma, the most common form of glaucoma, is chronic, with signs appearing late in the course of the disease, such as visual halo, corneal edema and, rarely, pain. Treatment is usually medical, with eye drops to reduce intraocular pressure;
- angle-closure glaucoma: always acute in onset, it is a therapeutic emergency, first medically and then surgically. Intraocular pressure is very high, above 50 mm of mercury. The symptoms are sudden, with acute pain in a red eye with a semi-dilated pupil that doesn’t respond to light, retracting and reducing visual acuity. Sometimes accompanied by nausea and vomiting. Angle-closure glaucoma can occur in certain hypermetropic subjects, or in predisposed individuals who have had their pupils dilated by eye drops for a simple ophthalmological examination. It can be detected by measuring the angle between the iris and the cornea (gonioscopy).
Glaucoma, a disease with multiple risk factors
Glaucoma is a degenerative neuropathy that affects the optic nerve, progressively destroying the retinal ganglion cells. Its main risk factor is elevated intraocular pressure. Screening is therefore based on :
- Regular monitoring of this pressure ;
- Observation of the back of the eye and the visual field.
Other risk factors include high myopia, age, vascular factors (high blood pressure, arteriosclerosis, certain treatments that can lead to ocular hypertonia, i.e. increased pressure inside the eye) and sleep apnea.
Glaucoma diagnosis: a visit to the ophthalmologist every 2-3 years
He therefore recommends that everyone, from their forties onwards, visit their ophthalmologist every 2-3 years for a check-up. All the more so if there is a family history of the condition.
Diagnosing glaucoma: the tests to be carried out
Screening for glaucoma involves a number of simple, painless tests:
- Measuring eye pressure with a tonometer: the ophthalmologist can use a non-contact, eye-drop-free method, by blowing a jet of air into the eye, or, alternatively, using a plastic cone placed on the eye after instilling an anaesthetic eye-drop;
- An ophthalmoscope is used to examine the back of the eye, enabling the doctor to determine the presence or absence of damage to the optic nerve.
Once the diagnosis has been made, the ophthalmologist may perform two other examinations:
- One that evaluates the visual field;
- The other examines the iridocorneal angle (gonioscopy), to determine the nature of the glaucoma and how advanced it is.
Glaucoma: treatment options
There are different types of treatment, depending on the nature of the glaucoma, its severity and the patient’s age. It can be :
- Medical (eye drops). New galenic formulas have appeared on the eye drops market, offering preservative-free, sustained-release products. Unlike “classic” eye drops, which have to be instilled at a set time, several times a day, these new products only need to be taken once a day, at a rate of two or three drops a day. This simplification should improve compliance with treatment;
- Physical. In some cases, laser treatment may be preferable, particularly in cases of ocular surface pathology. However, its effect is not permanent, and treatment must be repeated every 3-4 years.
- Another approach is ultrasound. Ultrasound acts on the ciliary body, which produces aqueous humor, by reducing its production in order to lower intraocular pressure. Treatment is ambulatory (no hospitalization) and has a success rate of 60% at 1 year, says the doctor. In many cases, eye drops will have to be reapplied a few months later.
- Surgical. Surgery is the only option. Here again, this technique does not guarantee success in 100% of cases. Its choice must therefore be discussed with the patient, depending on the progress of his glaucoma, his ocular characteristics, the risks of surgery, and so on. It is generally reserved for patients who are resistant to medical and laser treatment, and in whom the disease continues to progress.