Glaucoma is a condition in which fluid pressure rises within the eye. This causes irreversible optic neuropathy which leads to loss of visual field and. Without treatment, it can damage the optic nerve and lead to vision loss.
Glaucoma is relatively common. It is most likely to affect white people after the age of 60 and Black and Hispanic people after the age of 40.
The symptoms of the most common type — open-angle glaucoma — start slowly and are hard to notice. However, an ophthalmologist may detect changes during an eye test.
What is glaucoma?
The word glaucoma means originally meant “clouded”in greek.
Glaucoma refers to a buildup of pressure within the eye that causes damage to the optic nerve. Glaucoma is defined as a disturbance of the structural or functional integrity of the optic nerve that can usually be arrested or diminished by adequate lowering of IOP.(intraocular pressure)
The front part of the eye contains a clear fluid, the aqueous humor. This fluid nourishes the eye and gives it its shape. The eye constantly produces this fluid and drains it away through a drainage system.
If a person has glaucoma, the fluid drains slowly out of the eye. When this happens, fluid builds up, and pressure inside the eye rises.
If a person does not manage this pressure, it may damage the optic nerve and other parts of the eye, leading to vision loss.
Glaucoma usually affects both eyes, although it may affect one eye more severely than the other.
Causes and risk factors
Experts do not know exactly what causes glaucoma, but some health conditions increase the risk.
If a person has primary glaucoma, there is no identifiable cause. If they have secondary glaucoma there is an underlying cause, such as a tumour ,diabetes, hypothyroidism and advanced cataract or inflammation.
Risk factors for glaucoma include the following:
- for white people, being over 60 years old
- for Black and Hispanic people, being over 40 years old
- having diabetes or another underlying health condition
- a family history of glaucoma
- having an eye injury or condition
- previous eye surgery
- severe myopia (nearsightedness)
- taking corticosteroid medication, especially as eye drops
- high blood pressure
- genetic factors, which can lead to childhood glaucoma
There are several types of glaucoma, including:
- open-angle glaucoma
- closed-angle glaucoma
- normal tension glaucoma
- pigmentary glaucoma
Also known as chronic glaucoma, this is the most common type. It develops slowly, and a person may not notice any symptoms, even if slight vision loss occurs.
Many people with this type of glaucoma do not seek medical help until permanent damage has already occurred.
Normal tension glaucoma
In this type of glaucoma pressure inside the eye is normal but optic nerve damage still occurs.
This is also known as acute angle-closure glaucoma. It can start suddenly with pain and rapid vision loss.
As the symptoms are noticeable, the individual will usually seek medical help, resulting in prompt treatment. This can prevent permanent damage
This is a type of open-angle glaucoma that typically develops during early or middle adulthood.
It involves changes in the pigment cells that give color to the iris. In pigmentary glaucoma, the pigment cells disperse throughout the eye.
If the cells build up in the channels that drain fluid from the eye, they can upset the normal flow of fluids in the eye. This can lead to a rise in eye pressure.
Congenital glaucoma/Childhood glaucoma
In rare cases, glaucoma can children due to genetic factors. The child may have:
- unusually large eyes
- excessing tearing
- cloudiness in the cornea
- sensitivity to light
Medication and surgery can help prevent vision loss.
The symptoms of the two most common types of glaucoma are different.
Symptoms develop slowly, and a person may not notice them until the later stages.
- gradual loss of peripheral vision, usually in both eyes
- tunnel vision
The symptoms of acute glaucoma appear suddenly and include:
- eye pain, usually severe
- blurred vision
- nausea and possibly vomiting
- seeing halo-like glows around lights
- red eyes
- sudden, unexpected vision problems, especially in poor lighting
Ophthalmologists regularly check for glaucoma as part of a routine eye test. They can use several diagnostic tests:
The eye doctor puts drops into the eye to widen the pupil, then examines the inside of the eye using a special light and magnifying glass.
The doctor carries out a visual field test to check the person’s peripheral (side) vision. The person looks straight ahead while the doctor presents a light spot in different places around the edge of their vision. This helps create a map of what the person can see.
After using eye drops to numb the eye, the doctor measures the pressure in the eye with a device that either touches the cornea (applanation) or uses a puff of air.
The doctor uses eye drops to numb the eyes, then places a type of contact lens on the eye. The lens has a mirror that that can show if the angle between the iris and the cornea is normal, too wide (open), or too narrow (closed).
The doctor places a probe on the front of the eye to measure the thickness of the cornea. The doctor will take this into account when they assess all the results, as corneal thickness can affect eye pressure readings.
Treatment aims to improve the flow of fluid from the eye, reduce fluid production, or both.
Most people will use eye drops as initial treatment. These either reduce the amount of fluid the eye makes or improve drainage.
It is essential to follow a healthcare professional’s instructions carefully for the best results and to prevent adverse effects.
Examples of eye drops include:
- carbonic anhydrase inhibitors
- cholinergic agents
- beta blockers
- nitric oxide releasers
- rho kinase inhibitors
Adverse effects can include:
- change in eye color or skin around the eye
- dry mouth
- occasionally, retinal detachments or difficulty breathing
If the adverse effects persist, the doctor may change the dose or recommend a different option.
Bottom of Form
If drugs do not help, or if the person cannot tolerate them, a doctor may recommend surgery.
Surgery usually aims to reduce the pressure inside the eye. Possible interventions include
- Laser procedures: Yag iridotomy
- Trabeculoplasty: The surgeon uses a laser beam to unblock clogged drainage canals, making it easier for fluid to drain out.
- Filtering surgery: If laser surgery does not help, the surgeon may open channels in the eye to improve fluid drainage.
- Drainage implant: This may help if glaucoma occurs in children or as a result of another health condition. The surgeon inserts a small silicone tube into the eye to improve drainage.
- Recent advances like stents.
It is essential to have regular eye checks because this is the only way to detect glaucoma in the early stage.Glaucoma foundation recommend having a baseline test at the age of 40. The doctor will use the results to detect future changes.
A doctor can advise an individual on how often they should have an eye test, depending on their risk level.