Understanding the Different Types of Glaucoma
Primary Open-Angle Glaucoma
Primary open-angle glaucoma is the most common form of the disease, and it is often called the silent thief of sight because it causes no pain and few early symptoms. Regular eye exams are the most reliable way to catch it before significant damage occurs.
This type develops when the eye's drainage system, which is responsible for removing fluid and maintaining healthy pressure, becomes partially blocked over time. Even though the drainage angle looks structurally normal, microscopic resistance prevents fluid from flowing out efficiently. Pressure inside the eye gradually rises, placing stress on the optic nerve.
Primary open-angle glaucoma can affect one or both eyes and tends to progress at different rates in each eye. It accounts for the large majority of all glaucoma cases.
Several factors raise the likelihood of developing this condition. Knowing your personal risk profile can guide how often you should be screened.
- Age over 40, with risk increasing each decade
- Family history of glaucoma in a parent or sibling
- African American, Hispanic, or Asian ancestry
- Elevated eye pressure, also called ocular hypertension
- Thin corneas or a large cup-to-disc ratio in the optic nerve
- Diabetes, high blood pressure, or cardiovascular disease
- Severe nearsightedness, known medically as myopia
In the early stages, primary open-angle glaucoma produces no noticeable symptoms at all. As the condition advances, you may begin to lose side (peripheral) vision, notice difficulty seeing in low light, or experience subtle changes in depth perception. By the time these changes become obvious, meaningful vision loss has often already occurred, which is why routine screening matters so much.
Detecting this condition requires a thorough eye examination that goes beyond a basic vision check. A specialist will typically use several tests to get a complete picture of your eye health.
- Tonometry to measure pressure inside the eye
- Dilated optic nerve examination to assess nerve health
- Visual field testing to map peripheral vision
- Optical coherence tomography (OCT), an imaging scan that measures nerve fiber thickness
- Gonioscopy to examine the drainage angle directly
- Pachymetry to measure corneal thickness, which affects pressure readings
The primary goal of treatment is to lower eye pressure enough to stop or slow optic nerve damage. The right approach depends on how advanced the condition is and how your eye responds to therapy.
- Prescription eye drops such as prostaglandin analogs, beta-blockers, or alpha agonists
- Selective laser trabeculoplasty (SLT), a laser procedure that improves drainage
- Minimally invasive glaucoma surgery (MIGS) for mild to moderate cases
- Traditional surgery such as trabeculectomy for more advanced disease
- Glaucoma drainage implants when other surgical options are not suitable
Most people with well-controlled primary open-angle glaucoma maintain good, functional vision and continue their normal daily activities. Consistency with treatment, keeping all follow-up appointments, and promptly reporting any vision changes to your care team are the cornerstones of long-term success.
Angle-Closure Glaucoma
Angle-closure glaucoma occurs when the iris (the colored part of the eye) shifts forward and physically blocks the eye's drainage opening. It can develop suddenly as a medical emergency or gradually over time with few warning signs.
When the iris blocks the drainage angle, fluid cannot exit the eye, and pressure can rise rapidly. An acute attack can cause severe, permanent vision loss within hours if it is not treated immediately. A chronic form also exists in which the angle narrows slowly, producing mild or no symptoms until significant damage has occurred.
Anatomical features of the eye and certain demographic factors are the primary drivers of risk for this condition.
- People of Asian, Inuit, or Hispanic descent
- Women, who are affected more often than men
- Adults over 55, with risk rising with age
- Farsighted individuals (hyperopia), whose eyes tend to be shorter and more crowded
- A family history of angle-closure glaucoma
- Cataracts causing lens swelling
- Use of certain medications that dilate the pupils, including some antidepressants and decongestants
An acute angle-closure attack is a medical emergency. If you or someone you know experiences any of the following symptoms, seek emergency eye care immediately.
- Sudden, intense eye pain or severe headache
- Rapid blurring or loss of vision
- Seeing halos or rainbow rings around lights
- A red, watery eye
- Nausea or vomiting alongside eye symptoms
- An eye that feels unusually firm or hard to the touch
Delaying treatment even by a few hours can result in irreversible damage, so this situation should never be managed with a wait-and-see approach.
Chronic angle-closure develops more gradually and may cause only occasional mild discomfort, brief episodes of blurred vision, or halos around lights in low-light settings. Because the symptoms are subtle and intermittent, this form is often identified only during a routine eye exam.
Acute attacks require urgent treatment to rapidly lower eye pressure, which often involves medication followed by a laser procedure called laser peripheral iridotomy. This procedure creates a small opening in the iris to restore fluid flow and relieve pressure. Preventive laser treatment is frequently recommended for the other eye as well, since both eyes are often at risk. For ongoing management, regular monitoring is essential to detect any recurrence or progression.
Normal-Tension Glaucoma
Normal-tension glaucoma is a form of open-angle glaucoma in which the optic nerve is damaged even though eye pressure stays within the range typically considered normal (below 21 mmHg). It affects a meaningful portion of people diagnosed with open-angle glaucoma and can be more challenging to identify.
In this condition, optic nerve damage and progressive vision loss occur despite pressure readings that do not raise a red flag during a standard eye pressure check. Because the pressure alone does not signal a problem, the diagnosis often relies heavily on optic nerve imaging and visual field testing rather than pressure measurements alone.
Certain populations and health factors are associated with a higher likelihood of developing this type of glaucoma.
- People of Japanese ancestry, where this type is more frequently diagnosed
- Women, particularly after menopause
- Those with a family history of normal-tension or low-pressure glaucoma
- Individuals with conditions that affect blood flow, including low blood pressure (hypotension) especially at night
- People with a history of vasospastic disorders such as migraines or Raynaud's phenomenon
- Those with sleep apnea or other conditions that reduce blood oxygen levels
Researchers believe that factors beyond eye pressure play a meaningful role in this condition. These may include reduced blood flow to the optic nerve, increased nerve sensitivity, and immune-related processes that can affect nerve tissue. Because multiple contributing factors may be involved, treatment is often tailored to address the individual's broader health picture as well as their eye pressure.
Symptoms mirror those of standard open-angle glaucoma, with gradual peripheral vision loss that is easy to overlook. Comprehensive eye exams that include optic nerve imaging and visual field mapping are the most reliable way to detect this type. Treatment focuses on lowering eye pressure further below its current level, even though it already falls within the normal range, and may also include strategies to improve blood flow to the optic nerve such as managing blood pressure, treating sleep apnea, and incorporating regular moderate exercise.
Secondary Glaucoma
Secondary glaucoma develops as a consequence of another eye condition, injury, or medication rather than arising on its own. Because there is a specific underlying cause, effective management usually means treating both that cause and the elevated eye pressure simultaneously.
Any condition or substance that disrupts the normal flow of fluid inside the eye can lead to secondary glaucoma. Identifying and addressing the root cause is a critical part of treatment in these cases, since pressure reduction alone may not be sufficient if the underlying problem continues.
Several distinct forms of secondary glaucoma exist, each with a different underlying trigger.
- Inflammatory glaucoma caused by uveitis or other internal eye infections
- Steroid-induced glaucoma from prolonged use of corticosteroid medications
- Pigmentary glaucoma, in which pigment granules shed from the iris clog the drainage channels
- Pseudoexfoliation glaucoma, caused by protein deposits that accumulate inside the eye
- Neovascular glaucoma from abnormal new blood vessel growth, often linked to uncontrolled diabetes
- Traumatic glaucoma following a blunt or penetrating eye injury
- Lens-induced glaucoma arising from cataract complications or a dislocated lens
Symptoms vary considerably depending on the underlying cause and may include eye pain, redness, light sensitivity, vision changes, or halos around lights. Some types cause gradual vision loss similar to primary glaucoma, while others produce sudden symptoms that require prompt attention. Treatment combines managing the root cause with standard glaucoma therapies such as medicated eye drops, laser procedures, or surgery to reduce pressure and protect the optic nerve.
Congenital Glaucoma
Congenital glaucoma is a rare condition present from birth in which the eye's drainage system has not formed properly. Early recognition and treatment are critical, as delayed care can lead to permanent vision loss during the most critical period of a child's visual development.
When the drainage structures of the eye fail to develop normally before birth, fluid builds up inside the eye, raising pressure and potentially damaging the still-developing optic nerve. This elevated pressure can also cause the eye to enlarge abnormally, a sign that is often one of the first indicators of the condition.
Early identification often starts with an attentive parent or caregiver noticing something unusual about their child's eyes. The following signs warrant a prompt evaluation by an eye care specialist.
- Eyes that appear unusually large or noticeably different in size from each other
- A cloudy or hazy appearance to the cornea (the clear front surface of the eye)
- Excessive tearing when the child is not crying
- Strong sensitivity to light, causing squinting or covering the eyes
- Frequent eye rubbing or keeping the eyes closed
- Unusual fussiness that seems to improve in dimmer lighting
Surgery is typically the first and most effective treatment for congenital glaucoma, as eye drops alone are generally less reliable in very young children. Common procedures include goniotomy and trabeculotomy, both of which work by opening or creating drainage pathways to relieve pressure. With early surgical treatment, many children achieve good vision and develop normally. Lifelong follow-up care with an eye care team remains essential, as additional treatment may be needed as the child grows.
Frequently Asked Questions
Below are answers to common questions about glaucoma that can help guide your decisions and conversations with your care team.
Yes. Normal-tension glaucoma is a well-recognized condition in which the optic nerve is progressively damaged even when eye pressure falls within the standard normal range. This is one reason why a comprehensive eye exam, including optic nerve imaging and visual field testing, is more informative than a pressure check alone. If you have risk factors for glaucoma, ask your specialist whether additional testing beyond pressure measurement is appropriate for you.
Sudden severe eye pain, a rapid decrease in vision, or seeing halos or colored rings around lights may signal an acute angle-closure attack or another serious eye emergency. These symptoms require immediate medical attention at an emergency room or urgent eye care clinic. Do not wait to see if they resolve on their own, as permanent vision loss can occur within hours without treatment.
Treatment effectiveness is assessed through a combination of regular eye pressure measurements, optic nerve imaging, and visual field tests done over time. Stable results across multiple visits indicate that the disease is being controlled. It is important to attend all scheduled follow-up appointments even if you feel no symptoms, because glaucoma damage is silent and can progress without you noticing any change in your day-to-day vision.
Occasional missed doses are unlikely to cause immediate harm, but consistent use is essential for maintaining steady eye pressure control. If you miss a dose, take it as soon as you remember unless it is nearly time for your next dose, and never double up. If forgetting doses is a recurring problem, speak with your specialist about reminder tools, simplified dosing schedules, or longer-acting treatment options that may better fit your routine.
Yes. Juvenile open-angle glaucoma can develop in children and teenagers after infancy, and children can also develop secondary glaucoma as a result of eye injuries, steroid use, or other health conditions. Because glaucoma in younger patients is less commonly expected, it can sometimes be identified later than ideal. Any unexplained vision changes, eye enlargement, light sensitivity, or persistent tearing in a child should be evaluated promptly by an eye care professional.
While no lifestyle change can replace prescribed treatment, healthy habits can support your overall eye health and general circulation. Regular moderate-intensity exercise, a diet rich in leafy greens and omega-3 fatty acids, avoiding smoking, and moderating caffeine intake are commonly discussed options. For those with normal-tension glaucoma, managing blood pressure and treating sleep apnea may be especially relevant. Always discuss any significant lifestyle or supplement changes with your specialist before making them.
Protecting Your Vision Starts Here
Glaucoma is a lifelong condition, but with the right care it is one that most people can manage successfully and continue to enjoy good vision. Our team is committed to providing thorough, individualized evaluations and treatment plans tailored to your specific type of glaucoma and personal health needs. We welcome you to schedule a comprehensive eye exam so we can assess your risk, answer your questions, and work with you to protect your sight for years to come.
Dr. Chin is kind, professional, and provides thorough care. I recently had laser surgery for glaucoma and I’m very pleased with the results.
Michele Cucci
Dr. Chin is kind, professional, and provides thorough care. I recently had laser surgery for glaucoma and I’m very pleased with the results.
Michele Cucci
They did a very thorough analysis and found I had a scratched cornea. This will be my new go to for optometry.
Paula Clark
Dr. Fleischer and the Westwood Ophthalmology team are amazing. I had an eye injury and they fit me in. Dr. Fleischer was kind, courteous, knowledgeable. From front desk to doctors—A+ experience!
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Dr. Lee was extremely personable and comforting, answering all my questions about surgery. Already recommended him to many people.
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