Glaucoma: Definition, Symptoms, Types, Causes, Diagnosis, and Treatments

What Does Glaucoma Look Like?

An eye that is affected by glaucoma may look like a normal, unaffected eye from the outside, however, for the patient with glaucoma, changes to vision may cause blurriness, glare and difficulty with contrast. According to Hu CX, Zangalli C, Hsieh M, Gupta L, Williams AL, Richman J and Spaeth GL. in their paper, What do patients with glaucoma see? Visual symptoms reported by patients with glaucoma, patients with glaucoma may see blurriness and need more light to see objects clearly. People with glaucoma may also have tunnel vision, in which a person only sees what is in front of them. The image below shows what glaucoma looks like from an anatomical point of view as it develops, with the pressure building inside the eye, beginning to affect the optic nerve.

1. Tunnel Vision

Tunnel vision is a possible symptom of glaucoma in which a person only sees what is directly in front of them. Tunnel vision is caused by loss of peripheral vision which is the vision at the sides of your eyes. Loss of peripheral vision is one of the first symptoms of glaucoma, specifically open-angle glaucoma, according to Glaucoma Australia. Loss of peripheral vision is usually gradual. Loss of peripheral vision caused by glaucoma can not be cured, however, treatment such as eye drops may help to slow the progression of glaucoma and vision loss.

2. Blurred Vision

Blurred vision is a possible symptom of glaucoma. Blurred vision refers to a person’s sight being blurred or out of focus. According to Hu CX, Zangalli C, Hsieh M, Gupta L, Williams AL, Richman J and Spaeth GL. in their paper, What do patients with glaucoma see? Visual symptoms reported by patients with glaucoma, blurred vision can be a sign of early to moderate glaucoma. Blurred vision can also be a serious symptom of acute angle-closure glaucoma, according to Glaucoma Australia. If a person has sudden blurred vision, alongside symptoms such as eye pain, vomiting and nausea and halos around lights, this could be acute angle-closure glaucoma which is a medical emergency. Medical help should be sought immediately.

3. Red Eye

A red eye may be a symptom of acute angle-closure glaucoma, when in conjunction with other symptoms such as eye pain, nausea and vomiting. Acute angle-closure glaucoma is a serious condition and medical help should be sought straight away. Red eyes caused by acute angle-closure glaucoma usually refer to the conjunctiva, the membrane covering the white parts of the eye and the inner lining of the eyelid, becoming red.

4. Halos Around Lights

Halos around lights refer to the eyes seeing a bright halo or ring around sources of light. Seeing halos around lights is a possible symptom of chronic angle-closure glaucoma. Halos around lights can also be a sign of acute angle-closure glaucoma, if experienced alongside other symptoms such as the sudden onset of red eyes, eye pain, nausea and vomiting. Acute angle-closure glaucoma is a serious condition and you should get immediate medical help if you have these symptoms.

5. Headaches

Headaches are a possible symptom of glaucoma, particularly acute or secondary forms of glaucoma. Headaches are defined as discomfort in the head and face areas. Headaches can feel like a sharp pain or a dull ache. Headaches, alongside other symptoms such as halos around light sources, red eyes, eye pain, vomiting and nausea, can be an indication of acute angle-closure glaucoma which is considered a medical emergency. You should seek urgent medical assistance if you are experiencing these symptoms. According to the BrightFocus organisation, most forms of glaucoma do not cause headaches. However, acute and secondary forms of glaucoma can cause headaches due to the high pressure in the eye.

6. Vomiting and Nausea

Vomiting and nausea are not common symptoms of most types of glaucoma. Vomiting and Nausea are most often associated with acute angle-closure glaucoma. If a person has acute angle-closure glaucoma, they may also have symptoms such as red eyes, eye pain, headaches and see halos around lights. Acute angle-closure glaucoma is considered a medical emergency. You should seek urgent medical assistance if you are experiencing these symptoms.

7. Low Vision

Low vision is a general term that refers to permanent vision loss that affects daily life. Low vision is a possible symptom of glaucoma, caused by issues such as peripheral vision loss, loss of visual acuity and loss of colour contrast. Low vision is a term that refers to permanent vision loss that can not be fixed through corrective devices such as glasses or contact lenses, nor can it be fixed by surgery. Low vision can affect a person’s daily life, making activities such as driving or recognising faces difficult. According to Khanna A and Ichhpujani P. in the article, Low Vision Aids in Glaucoma, a high number of people with glaucoma have issues with vision that can be classified as low vision. Low vision caused by glaucoma can lead to issues with glare, colour contrast and visual acuity, making it hard to see and possibly impacting daily life.

1. Acute Angle-Closure Glaucoma

Acute angle closure is a medical emergency that requires immediate treatment. Acute angle-closure glaucoma, according to Glaucoma Australia, is the second most common type of glaucoma and occurs when there is a sudden narrowing of the eye’s intraocular fluid drainage angle. The symptoms of acute angle-closure glaucoma include eye redness, blurry vision, severe pain around and in the eye and nausea. Urgent treatment for acute angle-closure glaucoma is necessary as this type of glaucoma can cause blindness very quickly. According to the National Eye Institute, this occurs as the iris stops fluid from draining out the front of the eye causing a build-up.

2. Congenital Glaucoma

Congenital glaucoma is a rare type of glaucoma that is present at birth and early childhood, due to the incomplete development of the eye’s intraocular fluid drainage system which causes high eye pressure. According to the National Eye Institute, the symptoms of congenital glaucoma in children include cloudy eyes, sensitivity to light (photophobia), eyes that are larger than normal and excessive tear production (epiphora). Diagnosis for congenital glaucoma can often be made clinically according to the American Academy of Ophthalmology, meaning it may not require a measurement of the patient’s intraocular pressure. Although this can be necessary to diagnose this type of glaucoma.

3. Pigmentary Glaucoma

Pigmentary glaucoma is a type of secondary glaucoma that is characterised by the flaking off of the pigment in a person’s iris, blocking fluid from draining out of the eye. According to the American Academy of Ophthalmology, symptoms of pigmentary glaucoma are not typical, except for those who have visual field loss. Patients may experience blurry vision or haloes when looking at a light, particularly when they are exercising, which can be a result of irregular intraocular pressure elevation. According to Glaucoma Australia, pigmentary glaucoma is more commonly developed in people who are short-sighted, also known as myopia.

4. Open-Angle Glaucoma

Open-angle glaucoma is primary glaucoma which means it is not caused by another medical condition. According to Glaucoma Australia, open-angle glaucoma is typically caused by high intraocular pressure inside the eye that damages the optic nerve. The high pressure is typically due to an imbalance in the flow of fluid in the eye. There are typically no symptoms for primary open-angle glaucoma as most patients will not notice any vision changes and will not experience pain. According to the National Eye Institute, this type of glaucoma can result in blindness due to damage to the optic nerve and may be treated with medication, surgery or laser treatment.

5. Secondary Glaucoma

Secondary glaucoma is a category of different types of glaucoma that is caused by another eye problem or disorder. According to Glaucoma Australia, types of secondary glaucoma include pigmentary glaucoma, related to the iris, neovascular glaucoma, which occurs when the eye does not receive enough blood and oxygen, traumatic glaucoma, caused by a direct injury to the eye, uveitic glaucoma, the result of the eye condition uveitis, and steroid-induced glaucoma, caused by steroid medications. As with many types of glaucoma, symptoms are not usually experienced in the early stages which is why it is recommended to have an eye test at least once every two years so an optometrist can assess for eye diseases and conditions, including glaucoma.

6. Normal-Tension Glaucoma

Normal-tension glaucoma is characterised by normal intraocular pressure but there is still damage to the optic nerve. According to Glaucoma Australia, it is believed that normal-tension glaucoma is caused by a lack of ocular blood flow to the optic nerve which makes a person more susceptible to developing this type of glaucoma. As with many other types of glaucoma, patients typically experience no symptoms which is why early detection can be very difficult. Normal-tension glaucoma may be treated with eye drops that will lower eye pressure and surgery or laser treatment may be suggested to slow its progression in an attempt to preserve eyesight.

Who is at Risk for Glaucoma?

Those at risk for developing glaucoma are people who have the following contributing factors including having a family history of glaucoma, older age, having certain medical conditions, steroid use and eye injury. Those at risk for developing glaucoma and the contributing factors are listed below,

• People with a family history of glaucoma: People who have a family history of primary open-angle glaucoma, one of the most common types of glaucoma, are at higher risk of developing the eye condition, according to the Glaucoma Research Foundation.
• Older Age: Age increases the risk of developing glaucoma. Older people, particularly those over 60, are at a higher risk of developing glaucoma, according to the American Optometric Association.
• Medical Conditions: Medical conditions such as high or low blood pressure and diabetes can contribute to glaucoma, according to Health Direct.
• Steroid Use: Steroids or corticosteroids use is a risk factor for developing glaucoma. Steroids are an anti-inflammatory that can be used on the eye or taken as a tablet. Steroid use can increase eye pressure and heighten the risk of glaucoma, according to Glaucoma Australia.
• Eye Injury: Eye injuries can be a risk factor for glaucoma as they may lead to an increase in eye pressure, potentially leading to optic nerve damage, according to the American Optometric Association.

What Type of Eye Doctor Diagnoses Glaucoma?

The type of eye doctor that is involved in diagnosing glaucoma is an ophthalmologist. An optometrist may also diagnose glaucoma, however, they are not an eye doctor. Eye doctors refer to those with a medical degree and additional training in ophthalmology, which ophthalmologists have.

What are the Diagnostic Tests or Exams Required to Diagnose Glaucoma?

The diagnostic tests or exams that are required to diagnose glaucoma include a tonometry test, an ophthalmoscopy, a gonioscopy and a visual field test. The diagnostic tests or exams used to diagnose glaucoma are listed below.

• Tonometry test: A tonometry test assists in diagnosing glaucoma as it measures the pressure in your eyes, known as intraocular pressure.
• Ophthalmoscopy: An ophthalmoscopy is an exam that assesses the state of the optic nerve head and the retina, helping to determine if glaucoma is present.
• Gonioscopy: A gonioscopy is a test that examines how well the drainage system in the eye works, according to the Cleveland Clinic. The drainage system in the eye helps move fluid and maintain eye pressure in the eye, if this is not working properly, it may lead to glaucoma.
• Visual Field Test: A visual field test is used to measure how well a person’s peripheral vision works. As peripheral vision is the area of sight affected by glaucoma, a visual field test can be important in helping to diagnose this condition.

How Quickly Does Glaucoma Progress?

How quickly glaucoma progresses depends upon what type of glaucoma a person has, whether the glaucoma was detected early and what treatment a person is having for their glaucoma. Most types of glaucoma progress slowly, taking several years to develop. Open-angle or primary glaucomas for example may take years to progress, not showing symptoms until the condition has reached its later stages. Acute angle-closure glaucoma is a sudden onset of glaucoma that can progress rapidly and threaten vision if not treated quickly. It is important to keep up to date with regular eye tests to help detect glaucoma early to limit the amount of vision impairment.

Can Glaucoma be Reversed?

No, the vision damage caused by glaucoma can not generally be reversed. Treatment such as eye drops and surgery may help to preserve vision and prevent eyesight from getting worse, but it does not generally reverse the damage. However, research is underway to try and reverse vision loss from glaucoma. According to a 2020 article by Harvard University, researchers have begun to successfully reverse glaucoma like eye conditions in animals.

1. Medication

Medication is used as a form of glaucoma treatment. This type of oral medication is taken to lower eye pressure, also known as intraocular pressure, which is a known cause of glaucoma due to optic nerve damage. It does this by reducing the amount of aqueous humour secreted by the eye. According to Glaucoma Australia, glaucoma medication is often only taken for a short period of time as the effectiveness diminishes the longer it is taken. The types of glaucoma that may be treated with medication include open-angle glaucoma, congenital glaucoma, pigmentary glaucoma and normal tension glaucoma.

2. Eye Surgery

Eye surgery is used to treat glaucoma when the condition is unable to be helped by other forms of treatment such as medication, eyedrops and laser treatment. Surgery is often required for advanced and aggressive forms of glaucoma. According to Glaucoma Australia, the main types of glaucoma surgery are Trabeculectomy and Glaucoma Drainage Devices. Trabeculectomy is performed to lower the pressure inside a patient's eye, also known as intraocular pressure and has a success rate of 70-90%. Glaucoma Drainage Devices are devices used to control the fluid leaving the eye and are surgically implanted in the eye.

3. Eye Drops

Eye drops, like other forms of glaucoma treatment, are used to reduce intraocular pressure, which is the pressure inside the eye. According to Glaucoma Australia, eyedrops are used as the most common form of glaucoma treatment and some side effects include dry mouth, headaches, dilated pupils, red and itchy eyes and light sensitivity. Eye drops work by reducing eye pressure inside the eye, therefore reducing the risk of optic nerve damage which can lead to glaucoma. Eyedrops for glaucoma treatment will be prescribed by your healthcare provider and should be taken exactly as directed.

4. Laser Treatment

Laser treatment for glaucoma is used to improve the flow of aqueous humour and also helps this fluid drain more effectively within the eye. According to Glaucoma Australia, the types of laser treatments are Laser Peripheral Iridotomy, Selective Laser Trabeculoplasty, Argon Laser Treatment and Cyclodiode Laser Treatment. The types of glaucoma that may be treated by laser treatment, as discussed by the National Eye Institute, include open-angle glaucoma, normal-tension glaucoma, angle-closure glaucoma and pigmentary glaucoma.

What is the First Treatment for Glaucoma?

Medication including medicated eye drops, and Laser Trabeculoplasty are often some of the first treatment options for people with glaucoma, according to the American Academy of Ophthalmology. Treatment for glaucoma will be largely dependent on the type of glaucoma a person has and what stage the condition is at. For people with open-angle glaucoma, the first treatment may focus on reducing intraocular pressure through medication, according to Law SK. in the article, First-line treatment for elevated intraocular pressure (IOP) associated with open-angle glaucoma or ocular hypertension: focus on bimatoprost.

What Should You Avoid If You Have Glaucoma?

There are certain foods and lifestyle factors that should be avoided for people who have glaucoma, to help maintain eye health and assist in slowing glaucoma progression. Foods high in trans fats and saturated fats such as baked goods, fried foods, butter and meats such as sausages and bacon can raise cholesterol and blood pressure, potentially causing health conditions that may possibly worsen glaucoma if consumed in excess. It is also recommended that people with glaucoma avoid smoking as this may worsen glaucoma.

What is the Difference Between Glaucoma and Cataracts?

The differences between glaucoma and cataracts involve what parts of the eye they affect and the symptoms they present. Both glaucoma and cataracts are common eye conditions that can lead to vision issues including blindness, but these vision issues are different in their cause. Glaucoma refers to a group of eye diseases that damage the optic nerve, which can in turn lead to vision loss. Cataracts is an eye condition in which the lens of the eye becomes clouded due to a buildup of proteins which may lead to vision issues.