Glaucoma is a group of serious eye conditions when the optic nerve is being damaged, leading to progressive and irreversible vision loss. It is one of the leading causes of blindness for people age 60 and older. Even though glaucoma is more common in older adults, it can occur at any age.
Glaucoma is sometimes called the “silent thief of sight” because it slowly damages the eyes and can cause irreparable harm before there is any vision loss. But this disease is stealthy in more ways than one.
– Dr. Janey Wiggs, Massachusetts Eye and Ear Infirmary
The optic nerve damage is often, but not always, caused by abnormally high pressure in the eye. The optic nerve is a bundle of about 1 million individual nerve fibers that transmits the visual signals from the eye to the brain. Other theories suggest a lack of adequate blood flow to the optic nerve as possible cause for glaucoma.
By the time you notice vision loss symptoms, it may be too late. The vision loss cannot be restored and you can only save and maintain the current vision you have.
Different types of glaucoma will have different symptoms. The most common causes of glaucoma are listed below:
- Primary open-angle glaucoma, also called wide-angle glaucoma: this is the most common type of glaucoma, affecting at least 90% of all glaucoma cases, about 3 million Americans.It is caused by the slow clogging of the drainage canals, resulting in increased eye pressure (IOP). It is painless with no vision changes at first and will develop slowly as a lifelong condition. As the disease progress, you may experience:
- Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes
- Tunnel vision in the advanced stages
- Angle-closure glaucoma, also called closed-angle glaucoma, narrow-angle glaucoma: this is the less common form of glaucoma and is a medical emergency as it can cause blindness within a day of its onset. It is caused by blocked drainage canals when the angle between the iris and cornea is closing, resulting in sudden increase in internal ocular pressure (IOP). Angle-closure glaucoma can be chronic (progressing gradually) or acute (appearing suddenly). Please seek medical attention immediately if you experience:
- Severe headache
- Intense eye pain
- Nausea and vomiting
- Blurred vision
- Halos around lights
- Eye redness
- Secondary glaucoma: This is any type of glaucoma in which the increase in eye pressure was caused by another medical eye condition, physical injury, medication or in some rare occasion, eye surgery.
- Normal-tension glaucoma (NTG) or low-tension glaucoma: In this form of glaucoma, your optic nerve is damaged even though your eye pressure remains within the normal range. It is unclear why this would happen but some theorize that you may have abnormally sensitive optic nerve, or that you have lower blood flow going to the optic nerve due to a medical condition that impairs blood circulation, such as atherosclerosis, which is a hardening of the arteries from a buildup of fatty deposits (plaque) in the arteries.
- You may experience blind spots in your vision.
- Pigmentary glaucoma: Tiny bits of pigment granules from your iris (the colored part of your eye) break into the clear fluid and slowly clog or block your drainage canals. Rigorous physical activities like jogging may stir up the pigment granules and cause intermittent increase in eye pressure.
- Congenital Glaucoma: Infants and children may also have glaucoma due to a hereditary defect, an abnormal development during pregnancy when there’s incorrect or incomplete development of the eye’s drainage canals, or other medical conditions. For uncomplicated defect correction, microsurgery may be an option. For others, both surgery and medication would be required. Children with glaucoma may show the following symptoms:
- Unusually large eyes
- Excessive tearing
- Cloudy eyes
- Light sensitivity
When you arrive for your appointment, our optometrist will check for signs of glaucoma during the eye health check portion of your eye exam if you completed the optomap® retinal imaging or dilation. Visual field testing is also used to check if you have any blind spots in your vision, which is a common symptom of glaucoma.
Because most glaucomas progress so slowly with no vision loss symptoms in its earliest stage, our eye doctors use the most advanced technology in both retinal imaging and optical coherence tomography angiography (OCTA) to detect glaucoma early.
- We prefer the optomap® retinal imaging over dilation as it allows our optometrists to better gauge and monitor year-to-year changes to your retina and optic nerve, which therefore increases your chance to detect glaucoma early before you suffer irreversible vision impairment.
- Based on clinical findings, our eye doctor may also require an OCT/OCTA scan (ultrasound of your eye) to further measure Focal Loss Volume (FLV%), which is the current single best predictor of conversion to glaucoma according to the latest studies.
If you fall under one of the following categories, it is extremely important that you do a comprehensive eye exam (with eye health screening) instead of a basic routine eye exam during your annual check-up as you are more at risk of developing glaucoma:
- Age over 60: Each year of age slightly increases your risk of developing glaucoma. African Americans, Hispanics/Latinos are at increased risk after age 40.
- Race: African Americans are significantly more likely to get glaucoma than Caucasians, and they are much more likely to suffer permanent vision loss. People of Asian descent and Native Alaskans are at higher risk of angle-closure glaucoma. People of Japanese descent are more likely to develop low-tension glaucoma. Others of Irish, Russian, Hispanic, Inuit and Scandinavian descents are also at greater risk.
- Family history of glaucoma
- Medical conditions: Some studies indicate that diabetes, high blood pressure, heart disease, and sickle cell anemia may increase the risk of developing glaucoma.
- Physical injuries to the eye: Severe trauma, such as being hit in the eye, can result in immediate increased eye pressure. Internal damage from such a trauma can also cause future increases in pressure. Injury can also dislocate the lens, closing the drainage angle and increasing pressure.
- Other eye-related risk factors: thinner corneas and optic nerve sensitivity, conditions such as retinal detachment, eye tumors, eye inflammations… and high amounts of nearsightedness or farsightedness all increase your risk for developing glaucoma
- Corticosteroid use: Long-term use of corticosteroids (including cortisone, hydrocortisone and prednisone) appears to put some people at risk of getting secondary glaucoma.
For additional information, please visit one of the following resources and references:
- Glaucoma Research Foundation
- The Glaucoma Foundation
- International Glaucoma Association, “About glaucoma”
- National Eye Institute, “At a glance: glaucoma”
- Review of Optometry, Oct 2019, Wellness Essentials for Clinical Practice, see “The Nuts and Bolts of Nutrients” pg 8, “The Virtues of Vitamin C” pg 14, “Carotenoids: Front to Back Ocular Protection” pg 21, “Put Wellness on the Menu” pg 34