Glaucoma: symptoms, causes, treatment, and populations at risk
The majority of glaucoma patients are elderly. With the current standard of medical care, they can be well controlled as long as they take medication regularly.
What worries us most is that many of our elders have a poor concept of medication and often stop taking medicine without permission because they are afraid of trouble. On the contrary, this increases the risk of deterioration of their eyes and blindness.
Each year, more than 5 million people around the world go blind because of glaucoma, the second highest rate of blindness in the world.
According to Taiwan statistics, the number of people suffering from glaucoma in Taiwan has exceeded 340000. In particular, changes in the eye habits and lifestyle of modern people have led to an ever-expanding population at high risk.
Many ophthalmologists remind us that the majority of patients are often ill and do not know, if not treated in time to continue to deteriorate, will greatly increase the risk of blindness!
What is glaucoma?
Glaucoma is a visual field defect caused by optic atrophy. Although high intraocular pressure is likely to lead to glaucoma, high intraocular pressure is not the only index to judge glaucoma.
It’s not that high IOP is associated with glaucoma, it’s just that people with high IOP are at higher risk of developing glaucoma.
The normal person’s IOP should be between 10mm and 20mm Hg.If the IOP is too high for a long time, it will cause poor blood circulation of the optic nerve of the eyeball, after a series of course development, it may lead to blindness.
Possible ways to develop glaucoma:
High intraocular pressure, poor blood circulation of the optic nerve, optic atrophy, visual field defect (glaucoma), complete atrophy of the optic nerve lead to blindness (the most serious condition).
Of course, this development path is the least optimistic scenario, the sooner the disease can be brought under control, the greater the chance of delaying deterioration.
Why is there intraocular pressure?
The cornea and the lens of the eyeball are important structures for the eyes to receive light and image, and they must be kept in a transparent state.
In order to make cornea and lens transparent, the necessary condition is that no blood vessels can pass through, so the nutrition and metabolism of cornea and lens must depend on the supply of aqueous humor.
Aqueous humor is secreted by ciliary body, pass eyeball hind room first, flow through pupil to reach anteroom again, the trabecular meshwork of corner of anterior chamber is discharged next, flow into vein to return blood circulation finally.
In the case of fixed eye size, before and after the full of aqueous eye will form a force from the inside out, this force is called “intraocular pressure.”
Once the rate of aqueous humor discharge is less than the rate of manufacture, the force of the eyeball from the inside out will increase, resulting in elevated intraocular pressure.
High risk group of glaucoma.
The following groups may increase the incidence of glaucoma due to their own disease, heredity and so on. We should follow up the intraocular pressure and get the fundus examination on a regular basis.
- Acute anterior uveitis.
- Over 40 years of age.
- Cardiovascular disease.
- Had eye trauma.
- High myopia (over 600 degrees).
- Family history of glaucoma.
- Long-term use of steroids, especially eye drops
What symptom does glaucoma have?
Glaucoma is often asymptomatic in the early stages. Due to the predilection of advanced age, many older people will think that it is the decline of vision caused by old age. By the time the symptoms are aggravated, the condition is already quite serious.
When glaucoma develops symptoms, there are two main manifestations:
- Acute glaucoma: sudden elevation of intraocular pressure, blurred vision, eye pain, halo of the rainbow around the light source, and may be accompanied by headache, nausea, vomiting.
- Chronic glaucoma: the intraocular pressure rises gradually, the optic nerve will be damaged slowly, the patient often does not have the conscious symptom in the initial stage, often only then has the obvious vision defect or the central vision blurring in the later stage.
Keeping the right concept, early detection and treatment, to save the blindness crisis is a very important thing!
Types of glaucoma
There are several types of glaucoma. The two main types are open-angle and angle-closure. These are marked by an increase of intraocular pressure (IOP), or pressure inside the eye.
Open-angle glaucoma, the most common form of glaucoma, accounting for at least 90% of all glaucoma cases:
- Is caused by the slow clogging of the drainage canals, resulting in increased eye pressure
- Has a wide and open angle between the iris and cornea
- Develops slowly and is a lifelong condition
- Has symptoms and damage that are not noticed.
“Open-angle” means that the angle where the iris meets the cornea is as wide and open as it should be. Open-angle glaucoma is also called primary or chronic glaucoma. It is the most common type of glaucoma, affecting about three million Americans.
Angle-closure glaucoma, a less common form of glaucoma:
- Is caused by blocked drainage canals, resulting in a sudden rise in intraocular pressure
- Has a closed or narrow angle between the iris and cornea
- Develops very quickly
- Has symptoms and damage that are usually very noticeable
- Demands immediate medical attention.
It is also called acute glaucoma or narrow-angle glaucoma. Unlike open-angle glaucoma, angle-closure glaucoma is a result of the angle between the iris and cornea closing.
Normal-Tension Glaucoma (NTG)
Also called low-tension or normal-pressure glaucoma. In normal-tension glaucoma the optic nerve is damaged even though the eye pressure is not very high. We still don’t know why some people’s optic nerves are damaged even though they have almost normal pressure levels.
This type of glaucoma occurs in babies when there is incorrect or incomplete development of the eye’s drainage canals during the prenatal period. This is a rare condition that may be inherited. When uncomplicated, microsurgery can often correct the structural defects. Other cases are treated with medication and surgery.
Other Types of Glaucoma
Variants of open-angle and angle-closure glaucoma include:
- Secondary Glaucoma
- Pigmentary Glaucoma
- Pseudoexfoliative Glaucoma
- Traumatic Glaucoma
- Neovascular Glaucoma
- Irido Corneal Endothelial Syndrome (ICE)
- Uveitic Glaucoma
Treatment of glaucoma is divided into drug therapy, laser therapy, surgical treatment, the purpose is to reduce the patient’s intraocular pressure, in order to control the disease, prevent deterioration.
Including eye drops, oral medicine, intravenous administration, the purpose is to reduce the secretion of aqueous humor or increase the outflow of aqueous humor, to avoid rising intraocular pressure. Depending on the individual patient’s condition, the appropriate treatment will need to be evaluated by a physician.
Some drugs may cause arrhythmia, asthma attacks, and so on, if there is physical discomfort after medication, should return to the doctor as soon as possible.
The damage caused by optic atrophy is irreversible. Once the optic nerve atrophy can not be recovered, it can not be treated with drugs.
According to the different situation of the corner, it can be divided into two types: laser trabeculectomy for the treatment of the corner opening, and laser iris perforation for the corner closure.
The function of laser therapy is to increase the discharge of aqueous humor, and treatment operation time is short, no wound, can be carried out in the outpatient department do not need to be hospitalized. After laser, the intraocular pressure must be controlled with medication.
Glaucoma surgery is the most common trabeculectomy, because of drug development and laser technology advances, glaucoma patients currently need surgery is less likely.
If the control effect of both drugs and laser therapy is not good, it is necessary to use surgical treatment as treatment.
Glaucoma does not necessarily cause blindness, but it must be well controlled to prevent it from worsening and reduce the risk of blindness. If you are a high-risk group, you should follow up your IOP regularly and have a fundus exam.
Reference:The types of glaucoma articles come from:https://www.glaucoma.org/glaucoma/types-of-glaucoma.php