Definition of glaucoma
Glaucoma is an increase in intraocular pressure within the eye, by excess and / or excessive retention of the aqueous humor.
We distinguish acute glaucoma, occurring suddenly, chronic glaucoma (80% of cases) progresses insidiously.
Glaucoma is called "closed-angle" when the angle between the iris and the cornea is very narrow, and "open angle" when no angle closure was observed.
Risks and consequences of glaucoma
Chronic open-angle glaucoma is seen in all ages but is most common after age 40.
It is desirable to make it a routine screening from 70 years because it is the second cause of blindness in developed countries after macular degeneration related to age. 10% of global visual impairment due to glaucoma according to WHO (Action Plan against blindness, 2006-2011).
According to the Society of Ophthalmology (SFO), chronic glaucoma affects about one million A press conference of its 2011 congress, the SFO evokes up to a million people, but unaware of their disease.
The danger of glaucoma is the alteration of sight until total blindness if left unchecked. The decrease in visual acuity indicates an advanced form of glaucoma which should no longer be with a proper care.
The acute form is urgent: acute glaucoma can cause blindness in 48 hours by compression of the optic disc area of the retina where the optic nerve emerges and blood vessels.
When glaucoma, slow compression of the optic disc gradually narrows the visual field (first peripheral vision) and central visual acuity (ability to distinguish two points when looking straight ahead).
Causes and origins of glaucoma
Aqueous humor is secreted fluid in the eye with a special area called "ciliary body", located on the outskirts of the lens. It is normally flows through resorption in the trabecular meshwork located in the iridocorneal angle (between the iris and the cornea). Many circumstances may inhibit or block this resorption. Since the production of aqueous humor does not stop for all that, the pressure increases faster or slower depending on the nature of the obstacle.
Old age affects the trabecular meshwork, which absorbed more slowly the aqueous humor.
The shape of the eye affects the anatomy of the anterior chamber angle. The eye very shortsighted closes the anterior chamber angle, which can block the flow of aqueous humor while the trabecular meshwork is "normal". The addition of other factors contributing to angle-closure glaucoma can cause an acute angle-closure.
Among these factors is the dilalation of the pupil (iris opening) by drugs and narcotics, by autonomic imbalance. Such parasympathetic hypertonia in the dark, cold, pain, stress or excitement. Trauma or ocular inflammation may also close the iridocorneal angle.
Finally, the presence of chronic diseases altering the arteries of the retina (mainly diabetes and / or hypertension) makes the papilla very sensitive to lower intraocular pressure. So we made a lot easier when you already acute glaucoma is a chronic glaucoma, especially if it is ignored, and when you suffer from diabetes or high blood pressure.
10% of glaucoma are called "closed angle"; it is most often an inherited anatomical anomaly. All other glaucoma are said to "open angle": the resorption of aqueous humor is the only cause, without angle anomalies.
Symptoms and signs of glaucoma
When chronic glaucoma moved silently and can not be manifested as blurred vision and reduced visual field. This is the regular monitoring of vision and eyestrain that can detect it.
In acute glaucoma, the eye suddenly becomes painful (but not always), very red (vessels dilate), and hard. The vision is blurred and not corrected with glasses or a magnifying glass. Mydriasis (constant enlargement of the pupil) is often present. Other symptoms should alert as headaches, nausea, or general malaise.
Will it possible prevention of glaucoma?
Yes, by the early detection of glaucoma factors, particularly advancing age. Consult an ophthalmologist regularly from the age of 40 years, even more so when a parent is already suffering from glaucoma.
Of course, avoid as much as possible situations that place the parasympathetic hypertonia: dark, cold, emotions, coffee, pain, stress, smoking, certain medications such as antihistamines, antispasmodics and antipsychotics.
It is recommended to avoid coffee increases the intraocular pressure and tobacco. However, the abuse of television, wearing lenses, reading or computer work are not sufficient in themselves risk.
When to see the doctor?
Systematically by regular eye balances to avoid an emergency situation, very dangerous for the view.
Emergency when acute glaucoma are signs: red eye, hard to palpation closed eyelid, vomiting, headache, blurred vision uncorrectable.
How to prepare for my consultation?
We must stand with the summary of all prescription treatments because some favor glaucoma.
What does the doctor?
The GP suggests the diagnosis for consideration and guidance urgently to a city in ophthalmologist or hospital if it is an acute glaucoma. He does the same for glaucoma but consultation may not take place within two hours.
He may prescribe eye drops immediately adapted to reduce the first pressure by draining the aqueous humor and then closing the pupil, which releases the iridocorneal angle. These are beta blockers, miotics, adrénaliniques, inhibitors of carbonic anhydrase, derivatives of clonidine and prostaglandins.
The emergency measure eye pressure (tonometry) and examination of the fundus, performed by an ophthalmologist in town or in the hospital, confirmed the diagnosis of glaucoma. Added to gonioscopy and exploration of the visual field that evaluate its causes and consequences eye.
Depending on the size of glaucoma or in case of ineffective treatments eyedrops, surgery with or without laser may be necessary.
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