What is Glaucoma?
Glaucoma is where the eye’s optic nerve, which relays visual information to the brain, is damaged with or without raised intraocular pressure. Normal intraocular pressure (IOP) is 10–21 mmHg. This leads to vision changes. If untreated, this will cause gradual vision loss.
Types of Glaucoma
Glaucoma is a group of eye diseases that can cause damage to the optic nerve and lead to vision loss or blindness. There are many different types of glaucoma. Some of the most common types are listed below.
A.) Open-Angle Glaucoma
Open-angle glaucoma is often called the "silent thief of sight" because it can develop slowly and without symptoms until significant damage has occurred to the optic nerve.
Open-angle glaucoma is the most common type of glaucoma, a progressive eye disease that can lead to vision loss and blindness. It is caused by gradual damage to the optic nerve, which carries visual information from the eye to the brain.
In open-angle glaucoma, the angle between the iris and cornea is open, allowing fluid to circulate freely in and out of the eye. However, the drainage system in the eye becomes less efficient with age, leading to a buildup of fluid and increased eye pressure, known as intraocular pressure (IOP). Over time, the elevated IOP damages the optic nerve fibers, causing vision loss.
Symptoms of Open Angle Glaucoma
Open-angle glaucoma usually develops gradually and without noticeable symptoms, it is often called the "silent thief of sight". In fact, many people with open-angle glaucoma are not aware they have the condition until significant vision loss has occurred. This is why regular eye exams are important for early detection and prompt treatment.
People with open-angle glaucoma may experience the following symptoms:
1.) Gradual loss of peripheral vision
This is often the first symptom of open-angle glaucoma. Over time, you may notice that your peripheral vision is becoming narrower, making it more difficult to see objects or movements out of the corner of your eye.
2.) Patchy blind spots
As the disease progresses, you may develop patchy blind spots in your field of vision, which can become larger and more numerous over time.
3.) Tunnel vision
In advanced cases, you may experience tunnel vision, where your field of vision becomes extremely narrow and you can only see objects directly in front of you.
4.) Halos around lights
You may see halos or circles around lights, especially at night.
5.) Eye pain or headache
In rare cases, open-angle glaucoma can cause eye pain or headache, particularly during an acute episode of increased eye pressure.
Open-angle glaucoma typically develops slowly and without any obvious symptoms in the early stages, which is why regular eye exams are crucial for early detection and treatment. As the disease progresses, symptoms may include blurred vision, the appearance of halos around lights, loss of peripheral vision, and eventually, complete blindness.
B.) Angle-Closure Glaucoma
Closed-angle glaucoma, also known as angle-closure glaucoma, is a type of glaucoma characterized by a sudden increase in eye pressure caused by a blockage in the flow of fluid within the eye.
This type of glaucoma occurs when the iris, the colored part of the eye, is positioned too close to the drainage angle in the eye, blocking the outflow of fluid. This type can show gradually or suddenly; if sudden then it involves severe eye pain, blurred vision, redness of the eye, mid-dilated pupil, and nausea.
Symptoms of Acute Angle Glaucoma
Closed-angle glaucoma, also known as angle-closure glaucoma, is a less common form of glaucoma that can develop suddenly and cause severe symptoms. Some common symptoms of closed-angle glaucoma include:
1.) Severe eye pain
Closed-angle glaucoma can cause intense, throbbing pain in the affected eye, often accompanied by a headache.
2.) Sudden vision disturbances
You may experience sudden blurring or haziness in your vision, or notice colored halos around lights.
3.) Nausea and vomiting
The intense pain associated with closed-angle glaucoma can trigger nausea and vomiting in some people.
4.) Redness and swelling
The affected eye may appear red, swollen, and teary.
5.) Reduced or cloudy vision
As the disease progresses, you may experience a gradual loss of vision or notice that your vision has become cloudy or foggy.
If you experience any of these symptoms, especially severe eye pain or sudden vision changes, it is important to seek immediate medical attention. Closed-angle glaucoma is a medical emergency and can lead to permanent vision loss if not treated promptly.
C.) Normal-Tension Glaucoma
Normal tension glaucoma (NTG) is a type of glaucoma, a progressive eye disease that can lead to vision loss and blindness. Unlike other forms of glaucoma, NTG is characterized by normal or low eye pressure, making it more difficult to diagnose and treat.
In a healthy eye, the clear fluid called aqueous humor is produced and drained continuously, maintaining a balance of pressure within the eye. However, in NTG, the eye nerve fibers are damaged even when the eye pressure is within a normal range. The cause of this damage is not yet fully understood, but some possible risk factors include poor blood flow to the eye, genetics, and certain medical conditions such as cardiovascular disease.
Normal tension glaucoma is associated with general issues of blood circulation and organ perfusion like arterial hypotension.
Symptoms of Normal-Tension Glaucoma
The symptoms of Normal tension glaucoma may include:
1.) Gradual vision loss
This is often the first symptom and is typically noticed as a gradual reduction in peripheral (side) vision.
2.) Changes in visual acuity
Some people with normal tension glaucoma may experience fluctuations in visual acuity, with the vision becoming clearer at times and more blurry at others.
3.) Halos around lights
Some people with normal tension glaucoma may notice halos around lights, especially at night.
4.) Eyestrain or headaches
Some people with normal tension glaucoma may experience eyestrain or headaches, especially when performing visually demanding tasks.
5.) Unusual visual sensations
Some people with normal tension glaucoma may experience visual sensations such as floaters or flashes of light.
It is important to note that many of these symptoms are non-specific and may be caused by a wide range of ocular and non-ocular conditions, and a proper diagnosis can only be made by an eye care professional.
D.) Congenital Glaucoma
Congenital glaucoma, also known as infantile glaucoma, is a rare type of glaucoma that is present at birth or develops during the first few years of life. It occurs when the eye's drainage structures do not develop properly during fetal development, leading to a buildup of fluid and increased pressure in the eye.
The symptoms of congenital glaucoma typically appear in the first few months of life and may include cloudy or enlarged eyes, sensitivity to light, excessive tearing, and eye redness. As the condition progresses, the pressure inside the eye can cause damage to the optic nerve, leading to vision loss and potentially irreversible blindness if left untreated.
Diagnosis of congenital glaucoma typically involves a comprehensive eye exam, including measurement of intraocular pressure and examination of the eye's drainage structures. Additional testing, such as visual field testing and optic nerve imaging, may also be performed to assess the extent of vision loss and monitor disease progression.
Treatment for congenital glaucoma usually involves surgery to lower the pressure inside the eye and prevent further damage to the optic nerve. The most common surgical procedure is trabeculectomy, which involves creating a tiny incision in the eye's drainage structures to improve fluid outflow. In some cases, medications may also be used to reduce intraocular pressure.
Early diagnosis and prompt treatment are crucial for managing congenital glaucoma and preventing vision loss. Children with congenital glaucoma should receive regular eye exams throughout childhood and into adulthood to monitor disease progression and adjust treatment as needed.
E.) Pigmentary glaucoma
Pigmentary glaucoma is a type of open-angle glaucoma that is caused by the accumulation of pigment in the drainage channels of the eye. This buildup of pigment can obstruct the outflow of aqueous humor, the fluid that nourishes the eye, leading to an increase in intraocular pressure (IOP). High IOP can cause damage to the optic nerve and lead to vision loss.
The symptoms of pigmentary glaucoma are similar to those of other types of open-angle glaucoma, including a gradual loss of peripheral vision, eye pain, headache, and halos around lights. However, in some cases, patients may not experience any symptoms until the disease has progressed to an advanced stage.
Diagnosis of pigmentary glaucoma involves a comprehensive eye exam that includes measuring IOP, examining the optic nerve, and assessing the drainage channels of the eye. Special tests such as gonioscopy and pachymetry may also be performed to determine the extent of pigment accumulation and assess the thickness of the cornea, respectively.
Treatment for pigmentary glaucoma is similar to other types of open-angle glaucoma and involves lowering IOP to prevent further damage to the optic nerve. This may be achieved through the use of eye drops, oral medications, laser therapy, or surgery. Patients with pigmentary glaucoma need to have regular follow-up visits with their eye doctor to monitor their condition and ensure that their treatment is effective.
F.) Exfoliation Glaucoma
Exfoliation glaucoma, also known as pseudoexfoliation glaucoma, is a type of glaucoma that occurs when abnormal deposits of protein accumulate on the surface of the lens in the eye. These deposits can also affect other parts of the eye, including the trabecular meshwork, which is responsible for draining aqueous humor, the fluid that nourishes the eye. This buildup of protein can lead to an increase in intraocular pressure (IOP), which can damage the optic nerve and lead to vision loss.
The symptoms of exfoliation glaucoma are similar to those of other types of glaucoma and may include blurred vision, loss of peripheral vision, and difficulty seeing in low-light conditions. However, many people with exfoliation glaucoma do not experience any symptoms until the disease has progressed to a more advanced stage.
Exfoliation glaucoma is typically diagnosed through a comprehensive eye exam, which may include measuring the intraocular pressure, examining the optic nerve, and performing a visual field test. Additional tests, such as gonioscopy, may be used to evaluate the drainage angle of the eye and determine the severity of the disease.
Treatment for exfoliation glaucoma typically involves lowering intraocular pressure through the use of medications, such as eye drops, or surgical intervention, such as trabeculectomy or laser trabeculoplasty. Regular monitoring and management of the disease is important to prevent vision loss and maintain overall eye health.
G.) Uveitic glaucoma
Uveitic glaucoma is a type of glaucoma that is caused by inflammation in the eye, particularly in the uvea, which is the middle layer of the eye that contains blood vessels. The inflammation can lead to increased pressure inside the eye, which can damage the optic nerve and lead to vision loss.
Read more: Uveitis
Symptoms of uveitic glaucoma may include blurred vision, eye pain, redness, and sensitivity to light. These symptoms can occur suddenly or develop gradually over time and may be accompanied by other symptoms of uveitis, such as eye floaters or cloudy vision.
Diagnosis of uveitic glaucoma typically involves a comprehensive eye exam, including measurements of intraocular pressure and a thorough evaluation of the uvea. Other tests, such as visual field testing and optical coherence tomography (OCT), may also be used to assess the extent of optic nerve damage.
Treatment of uveitic glaucoma depends on the underlying cause of the inflammation, as well as the severity of glaucoma. In some cases, the inflammation can be treated with medications such as corticosteroids or immunosuppressants, which can help to reduce intraocular pressure and protect the optic nerve. In other cases, surgery may be necessary to reduce intraocular pressure and prevent further vision loss.
Overall, early diagnosis and treatment of uveitic glaucoma are crucial for preventing permanent vision loss. Patients with uveitis should receive regular eye exams and should report any changes in vision or eye discomfort to their healthcare provider.
H.) Secondary Glaucoma
Secondary glaucoma is a type of glaucoma that occurs as a result of another eye condition or medical condition. Unlike primary glaucoma, which has no clear underlying cause, secondary glaucoma can be traced back to a specific trigger. This type of glaucoma can be caused by a wide range of factors, including injury, inflammation, infection, and medication.
There are several different types of secondary glaucoma, each with its own unique causes and symptoms. Some of the most common types of secondary glaucoma include:
1.) Neovascular glaucoma: This type of glaucoma occurs as a result of the growth of new blood vessels on the iris. This can be triggered by a variety of factors, including diabetes, ocular ischemic syndrome, and retinal vein occlusion.
2.) Traumatic glaucoma: Traumatic glaucoma occurs as a result of an injury to the eye. This can be caused by blunt force trauma, such as a blow to the head, or a penetrating injury, such as a cut or puncture wound.
3.) Uveitic glaucoma: Uveitis is a condition that causes inflammation in the eye, and it can lead to the development of glaucoma. This type of glaucoma is often associated with autoimmune disorders, such as rheumatoid arthritis and lupus.
4.) Pseudoexfoliation glaucoma: Pseudoexfoliation glaucoma occurs when tiny flakes of material build up on the surface of the eye. This can lead to increased pressure within the eye, which can cause glaucoma.
5.) Angle recession glaucoma: This type of glaucoma is caused by a tear or separation in the ligaments that hold the eye in place. This can occur as a result of a traumatic injury to the eye.
Symptoms of secondary glaucoma can vary depending on the underlying cause. However, some common symptoms of this type of glaucoma include:
- Increased pressure within the eye
- Blurred vision
- Eye pain
- Redness of the eye
- Halos around lights
- Headaches
Diagnosis of secondary glaucoma typically involves a comprehensive eye exam, which may include measuring the pressure within the eye, assessing the optic nerve, and checking for any signs of damage to the eye. Treatment for secondary glaucoma will depend on the underlying cause and may involve medication, surgery, or a combination of both.
Diagnosis of Glaucoma
Regular eye exams are important for detecting glaucoma in its early stages before vision loss occurs.
During a comprehensive eye exam, an ophthalmologist or optometrist will perform various tests to diagnose glaucoma. One of the most important tests is measuring the intraocular pressure (IOP) of the eye, which is typically done with a tonometry test. Elevated IOP is a key risk factor for glaucoma, but not all people with glaucoma have high IOP, and not all people with high IOP have glaucoma.
Additional Diagnostic Tests:
Other tests that may be performed include
1.) Ophthalmoscopy: To check the shape and color of the optic nerve.
2.) Perimetry: This test checks the patient’s ability to see the object clearly at several points.
3.) Gonioscopy: This test distinguishes between open-angle and closed-angle glaucoma.
4.) Pachymetry: This test is done to find out the thickness of the cornea.
It is important to note that a single abnormal test does not necessarily indicate glaucoma and a comprehensive evaluation is necessary to confirm the diagnosis. If glaucoma is suspected, additional testing and evaluation may be needed to determine the severity and appropriate treatment plan.
Treatment for Glaucoma
Treatment aims at reducing intraocular pressure (IOP) and preventing further damage to the optic nerves. Intraocular pressure can be reduced by increasing the drainage of aqueous humor or reducing its production through medications.
Medications:
Please note: The medications listed below are for reference only. Please consult your healthcare provider before taking any medications.
Intraocular pressure can be lowered with medications.
Beta-adrenergic antagonists: This helps by reducing the production of aqueous humor. These drugs are contraindicated in people with chronic obstructive pulmonary disease, asthma, or heart block.
Common drugs :
Timolol, Levobunolol, Carteolol, Metipranolol
Prostaglandin analogs: These are medications that help in the outflow of fluid from the eyes.
Common drugs :
Latanoprost, Travoprost, Bimatoprost, Tafluprost
Adrenergic agonists: These are medications that stimulate to reduce the production of aqueous humor and increase the outflow.
Common drugs :
Brimonidine
Carbonic anhydrase inhibitors: These are topical or oral medications that help in reducing eye pressure by decreasing the production of aqueous humor in the eye.
Common drugs :
Dorzolamide, Brinzolamide, Acetazolamide
Parasympathomimetic agents: Improve the outflow of aqueous humor from the eye. Usually recommended for open-angle glaucoma.
Common drugs :
Pilocarpine
Osmotic agents: These are used to treat sudden and severe rises in intraocular pressure. These are used in severe cases.
Common drugs :
Isosorbide, Mannitol
Surgery
Surgery may involve either laser or conventional surgeries. There are several surgical treatment options for glaucoma, including:
1.) Trabeculectomy:
This is the most commonly performed glaucoma surgery. The procedure involves creating a new channel for the drainage of fluid, bypassing the blocked drainage system in the eye. This procedure can lower eye pressure and reduce the risk of optic nerve damage.
2.) Drainage implant:
In this procedure, a small device is inserted in the eye to help drain fluid and lower eye pressure. The device can be placed in the front or the back of the eye.
3.) Cyclophotocoagulation:
This is a laser treatment that destroys some of the cells in the ciliary body that produce fluid, reducing fluid production and lowering eye pressure.
4.) Tube shunt:
In this procedure, a small tube is inserted into the eye to drain fluid and lower eye pressure. The tube is connected to a tiny reservoir under the conjunctiva, a thin membrane that covers the white of the eye.
5.) Goniotomy:
This is a minimally invasive procedure performed on infants and children with congenital glaucoma. The procedure involves making a small incision in the drainage angle to improve the flow of fluid and lower eye pressure.
The type of surgery recommended for a particular patient depends on several factors, including the type and severity of glaucoma, overall health, and other medical conditions. Your eye care professional can help determine the best surgical treatment option for your individual needs.
It is important to note that while surgery can help lower eye pressure and slow the progression of glaucoma, it does not cure the condition. Most people with glaucoma will require ongoing medical treatment, even after surgery.
Prognosis for Glaucoma
Glaucoma is a serious eye condition that can cause irreversible vision loss if left untreated. The prognosis for glaucoma varies depending on several factors, including the type and severity of the disease, the patient's age and overall health, and the effectiveness of treatment.
