Most people know glaucoma as a disease associated with diabetes and is caused by high intraocular pressure (pressure in the eye). I have explained its causes, types, symptoms, investigations, and treatment in detail in this article.
Glaucoma is optic neuropathy, which is a disease of the optic nerve that generally progresses over time. The optic nerve is the second cranial nerve that connects the eye to the brain. The optic nerve damage due to glaucoma is evident in the optic nerve head, the place where the optic nerve is connected to the back of the eye. Due to the optic nerve damage, there are changes in the visual field of the patient. The major modifiable risk factor in glaucoma is intraocular pressure (IOP).
The fluid inside the eye is called aqueous humor or aqueous. This fluid (99% water) is produced by the ciliary body in the eye. Most of the aqueous humor is drained through a structure known as the trabecular meshwork. The mechanical or functional block of trabecular meshwork leads to impaired drainage resulting in increased pressure inside the eye.
Based on whether a good portion of the drainage site is visible on examination or not, glaucoma is categorized into,
Open-Angle Glaucoma (Visible): This is the common type of glaucoma. It is also called wide-angle glaucoma. In this type, the drain structure, known as the trabecular meshwork, will look fine in the eye, but the fluid does not flow out as it should.
Angle-Closure Glaucoma (Not Visible): It is also called acute or chronic angle-closure glaucoma or narrow-angle glaucoma. It is more common in Asians. The eye will not be able to drain like it should because of the narrow drain space between the iris and cornea. This causes a sudden build-up of eye pressure. This glaucoma type is linked to farsightedness and cataracts. The ophthalmologist performs a test called gonioscopy to view the angle of the front part of the eye. The trabecular meshwork is one of the structures that make up the angle.
Other common types of glaucoma are:
Secondary Glaucoma: This secondary glaucoma occurs when another condition, like diabetes or cataract, adds pressure to the eye.
Normal-Tension Glaucoma: This is said to be a form of open-angle glaucoma. It occurs when there are blind spots in the vision or when the optic nerve is damaged even though the eye pressure is within the average range.
Pigmentary Glaucoma: In pigmentary glaucoma, tiny bits of pigment from the iris, which is the colored part of the eye, enters into the fluid inside the eyes and clogs the drainage canals.
Intraocular Pressure: It is directly proportional to the risk of developing glaucoma.
Family History: Peoplewith first-degree relatives having primary open-angle glaucoma are at a higher risk.
Age and Ethnicity: More in elderly and black individuals.
Others: Myopia and diabetes mellitus.
Most patients with glaucoma do not have any symptoms until it is too advanced. As a result, many patients are accidentally diagnosed with glaucoma during an eye check-up. Patients gradually lose their visual field till they are able to see only through a small island of vision. This is usually late in the course of the disease.
However, some patients who develop a sudden rise in IOP can have severe pain, headache, blurring of vision, colored halos, nausea, and vomiting. This usually occurs in an acute angle-closure attack when the patient suddenly develops closure of the angle leading to impaired aqueous drainage.
Apart from the routine procedures, the IOP is checked using an applanation tonometer. This is done with a device attached to the slit lamp, the machine with which an ophthalmologist examines the eye. Gonioscopy is done using a lens suited for the purpose of visualizing the angle of the eye. For both the above tests, topical anesthetic medication is instilled to numb the eye.
The optic nerve head is examined using a lens to check for the characteristic changes of glaucoma. The area surrounding the optic disc is assessed to see if there are any obvious retinal nerve fiber layer defects. The optic nerve head assessment may require your pupils to be dilated using a dilating drop.
If there is a suspicion or evident glaucoma, further tests may be done. These tests can be done to assess the level of damage to the optic nerve as well as the functional damage (loss of visual field).
Visual field analysis using perimeter (Humphrey or Octopus or Goldmann).
Optical coherence tomography helps to assess the optic nerve head and the retinal nerve fiber layer.
Heidelberg retinal tomography gives a detailed analysis of the optic nerve head.
All these tests can be done periodically to assess the progression of the disease.
1. Medical Treatment:
There are various eye drops, which decrease the production of aqueous or increase the drainage of aqueous from the eye, thus resulting in reduced IOP. As these usually give the desired decrease in IOP, they are usually preferred as the first-line treatment.
2. Surgical Treatment:
If the IOP is too high to be reduced with medicines or if maximal medical therapy does not result in the desired decrease in IOP, surgical management is opted for. A trabeculectomy is usually performed to reduce IOP. There are many newer techniques and implants that can also result in reduced IOP.
3. Laser Treatment:
Argon or selective laser trabeculoplasty is aimed at the trabecular meshwork to increase the outflow of aqueous. This can be done only for some types of glaucoma. A peripheral iridotomy (burning a small hole in the iris) using a laser is done in patients who are at the risk of developing angle-closure glaucoma.
Glaucoma cannot be prevented. But when it is detected earlier, the risk of eye damage becomes lowered. The following steps help to protect the vision:
It is important to get frequent eye examinations, so the sooner the doctor spots the glaucoma signs, the earlier the treatment can be started. Adults should get tested for glaucoma every 3 to 5 years. Above 40 years of age and with a family history of the disease, a complete eye examination every 1 to 2 years is needed. When there are other health-related problems like diabetes or other eye diseases, an ophthalmologist visit is often required.
When the doctor has diagnosed a high eye pressure, drops to prevent glaucoma will be given.
Moderate activities like jogging or walking at least three times a week are required, and practicing regular exercise leads to a healthier life.
Use protective eyewear while working on home improvement projects, watching TV, using phones, playing sports, etc.
Going for a regular follow-up visit is paramount. It is wise to stick to the dates of follow-up visits as advised by the treating ophthalmologist. This is necessary to assess the reduction in IOP as well as the progression of optic nerve head changes. A negligent attitude in patients with glaucoma can prove to be costly. Adherence to treatment and follow-up schedule should be emphasized enough.
The initial signs of glaucoma are usually loss of peripheral or side vision. Seeing halos like a rainbow-colored circle around lights or are unusually sensitive to light and vision loss, especially if it happens suddenly, could be a sign of glaucoma.
Steps to prevent the onset of glaucoma, especially in high-risk patients, are:
- Lowering your intake of saturated fats is an excellent first step.
- Aerobic exercises to prevent eye problems that cause glaucoma.
The first line of treatment given for glaucoma is a prescription of eye drops, which can help lower eye pressure, where some drops do it by reducing the quantity of aqueous fluid that the eye produces. In contrast, others reduce the eye pressure by directing the fluid flow through the drainage angle. Laser treatment is recommended if eye drops do not improve the symptoms, and surgery will be recommended in rare cases where eye drops or laser treatment has not been effective.
The common causes of glaucoma are:
- High fluid pressure in the eye.
- Genetics or family history.
- Blunt or penetrating eye injuries.
- Eye infection.
- Retinal vein occlusion.
- People above the age of 40.
- Thin cornea.
- History of eye surgery.
- Chemical eye injuries.
Yes, stress can cause glaucoma. Stress can play an essential role in the rise of the intraocular pressure of glaucoma. It also disturbs the amount of blood flow in the body by reducing blood and causing the reverse flow of venous blood in the head.
The foods to be avoided in glaucoma, which increases the IOP (intraocular pressure) in your eyes, are trans-fatty acids (partially hydrogenated oils), such as fried foods like french fries, donuts, cookies, and goods like cakes can worsen your glaucoma.
Researchers suggest that patients with glaucoma should not sleep on one side because it may be associated with greater visual field (VF) loss in the lower-positioned eye. The intraocular pressure (IOP) can increase in the supine (lying face upward) position, especially in patients with glaucoma. Previous studies have also shown that sleeping in a sideways or lateral decubitus position can lead to greater IOP in the lower-positioned eye. Therefore, sleeping position can affect eye pressure.
TV (Television) can produce UV (ultraviolet) lights. These UV lights are harmful to the skin and eyes because they can cause skin cancer and eye problems. But glaucoma will not be caused by watching TV. The eye disorder which is caused by watching too much TV is myopia.
Crying can increase eye pressure, harming patients with glaucoma, making their situation worse and more dangerous.
Banana is rich in provitamin A carotenoids may offer a potential food source for alleviating vitamin A deficiency which is essential for sight. Burro bananas are packed with antioxidant chemicals and a mixture of essential minerals, boosting the eyes’ health. In a study, glaucoma, cataract, night blindness, and macular degeneration have decreased with regular intake of burro bananas.
The exercises that are not suitable for glaucoma are:
Situps and pullups.
- Running, biking, or swimming.
- Weightlifting, particularly bench presses and powerlifting.
Do not limit your life due to glaucoma because most glaucoma patients will never go blind. If diagnosed in the earlier stage, you may not lose much vision at all. In fact, for most glaucoma patients, life does not change except for more frequent doctor’s visits and proper use of medications.
Foods rich in antioxidants and those suitable for eye health like cold water fishes such as sardines, salmons, mackerel, and spinaches, and other green leafy vegetables are good for glaucoma.
When consumed in large quantities, caffeine may cause an increase in eye pressure in a short time, says the Glaucoma Research Foundation.
If you have glaucoma, you may experience:
- Hazy or blurred vision.
- Severe eye and head pain.
- Rainbow-colored circles around bright lights.
- Nausea or vomiting with severe eye pain.
Even though glaucoma cannot be cured, we can manage it. Untreated acute glaucoma can result in permanent vision loss and progress to blindness within several years. Therefore, people with glaucoma need regular eye examinations and usually need to continue treatment for the rest of their lives.
Last reviewed at:
05 Feb 2022 - 5 min read
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