Pigment Dispersion Syndrome & Pigmentary Glaucoma

What are pigment dispersion syndrome and pigmentary glaucoma?

Pigmentary dispersion syndrome (PDS) is an uncommon eye condition that can cause early glaucoma. It happens when bits of the pigment in your iris break free and block fluid flow inside your eye.

PDS and pigmentary glaucoma (PG) are the same disease but at different stages of development. PDS can turn into (the technical term is “convert”) PG, usually over several years or even decades. PDS doesn’t always become PG, but the risk of it doing so increases the longer it’s been since you got the diagnosis.

How pigment dispersion syndrome can lead to glaucoma

The iris of your eye is a flat ring of muscle that contains melanin, the pigment that gives your eyes their color. In front of and behind your iris are spaces filled with a fluid called aqueous humor. Pressure from the aqueous humor helps your eye hold its globe-like shape.

When you have PDS, your iris can’t hold its shape and dips back too far. That makes the back of your iris press against the muscle fibers that control your lens shape. As your iris widens or narrows, the iris rubs against those fibers and pigment granules in the iris wear away, like flakes of paint chipping away from a piece of wood.

Once those granules are loose and floating in the aqueous humor, the flow of fluid carries them to other places inside your eye. The aqueous humor has a drainage system, the trabecular meshwork, and granules can accumulate in that meshwork and damage it. When that happens, aqueous humor fluid can’t drain out of your eye properly, causing high pressure inside your eye (ocular hypertension) and eventually causing glaucoma. Without treatment, glaucoma causes irreversible, severe vision loss and blindness.

What are the symptoms of pigment dispersion syndrome and pigmentary glaucoma?

PDS often doesn’t cause symptoms, so many people don’t know they have it. When it does, they’re usually similar to the most common glaucoma symptoms. Those include:

• Eye pain
• Eye redness
• Light sensitivity (photophobia)
• Seeing a glare or halos around lights

What causes pigmentary dispersion syndrome?

Experts don’t fully understand what causes PDS, but there are several possible contributing factors. The factors researchers know most about include:

• Genetics. Research connects several DNA mutations with PDS and PG. That’s why PDS and PG can run in families but it’s usually in an unpredictable way.
• Age. Diagnosis of PDS generally happens sometime between ages 20 and 50.
• Sex. PDS and PG disproportionately affect people assigned male at birth (AMAB).
• Race. People who are of Black or Asian descent have a lower risk for PDS and PG, while the risk for white people is higher.
• Being nearsighted. People with myopia (nearsightedness) have a higher risk of PDS and PG. The more nearsighted you are, the higher the risk of having PDS or having it turn into PG.
• Eye structure. PDS and PG are more likely to happen when you have a deep anterior chamber. A deeper chamber means it can hold more fluid, which can make the iris “bow” backward toward the lens. Having flatter corneas can also be a contributing factor.
• Excessive activity level. Research links PDS and PG to excessive exercise or physical activity. If you have PDS or PG, your eye specialist will likely ask about how physically active you are. If your activity level could contribute to your PDS or PG — either now or in the future — your specialist will likely recommend reducing your activity level.

Secondary pigment dispersion

There are other reasons why pigment granules might break free from your iris. When there’s another cause for pigment displacement, that’s called “secondary PDS.” It’s different from “primary PDS,” which means PDS that doesn’t happen because of another condition. But secondary PDS can still lead to PG.

Some causes of secondary PDS include:

• Eye injuries
• Tumors or growths inside your eye
• An artificial intraocular lens (IOL) that moves out of position

How are pigment dispersion syndrome and pigmentary glaucoma diagnosed?

The most useful test for detecting PDS before it causes symptoms is a routine eye exam.

Some of the changes that PDS or PG can cause that show up on an eye exam include:

• A Krukenberg spindle. This is a faint, vertical line in front of your pupil that’s the same color as your iris. It happens when higher pressure inside your eye pushes fluid forward and keeps loose pigment granules pressed against the inside surface of your cornea.
• Radial iris defects. These are thin lines on your iris with worn-away pigment. They look like the spokes on a bicycle wheel. An eye specialist can see them using special lighting techniques.
• Pigment accumulation near the outer rim of your iris. Your eye specialist can use a technique called gonioscopy to see pigment granules deposited there.

Tests your eye specialist may use

Several glaucoma tests can help with diagnosing PDS and PG. Some of these are common features of a routine eye exam, while others are a little more specific. Your eye specialist can tell you which tests they think will be the most helpful for diagnosing or ruling out PDS and PG.

These tests often include one or more of the following:

• Slit lamp exam
• Tonometry
• Optical coherence tomography
• Pachymetry
• Gonioscopy
• Visual field testing

How are pigment dispersion syndrome and pigmentary glaucoma treated?

The treatments for PDS and PG are very similar to treatments for other forms of glaucoma. The treatments can involve one or more of the following:

• Medications. Glaucoma medications lower pressure inside your eye in different ways. Some of them cause your pupil to relax more, improving aqueous humor drainage. Others slow the production of aqueous humor.
• Glaucoma surgery. This approach usually aims to improve fluid flow and drainage. Examples of glaucoma surgeries that do this include trabeculectomy, goniotomy and certain laser surgeries.

In many cases, a combination approach may offer the best results for people with pigment dispersion syndrome and pigmentary glaucoma. An example would be combining medications with laser surgery. This works well when medication alone doesn’t lower pressure inside your eye as much as you need.

Your eye specialist is your best source of information about treatment approaches. Your provider can advise you on how treatments are likely to affect you, what your alternatives are and what kinds of side effects you can expect.

Are pigment dispersion syndrome or pigmentary glaucoma preventable?

There’s nothing you can do to prevent PDS and PG. They happen unpredictably and people often don’t know they have these conditions until an eye specialist sees the changes during a routine eye exam or they start developing symptoms.

What can I expect if I have this condition?

Not everyone who has PDS will have it lead to PG. But the risk of it doing so goes up over time. About 10% of people with PDS will develop PG within 10 years. That number rises to 15% after 15 years. The lifetime risk is between 35% and 50%.

Because PDS and PG usually start much earlier in life than other forms of glaucoma, it’s important to manage this condition as best you can. Part of that is seeing your eye specialist for regular follow-ups.

Those visits can happen every three to six months or yearly, depending on the details of your case. Follow-up visits allow your provider to detect pressure increases and recommend treatment to prevent damage or at least stop it from getting worse.

Ongoing monitoring and managing of your PDS or PG are key to keeping your eyesight. It’s rare for people who prioritize follow-up visits and manage their condition based on their specialist’s recommendations to have permanent blindness.

How do I take care of myself if I have pigment dispersion syndrome or pigmentary glaucoma?

If you have PDS or PG, there are many ways you can help maintain your vision and prevent severe complications like vision loss.

• See your provider as recommended.
• Take medications as prescribed.
• Modify your lifestyle if your eye specialist recommends it.
• Call your provider if you notice changes in your vision, new symptoms or if you have concerns about your medications.

When should I go to the ER?

Some eye symptoms mean you need medical attention quickly. Not getting treatment can lead to irreversible eye damage. You should talk to your eye specialist after your diagnosis to learn about the symptoms that are most relevant to your specific case and what you should do if you have any of these symptoms.

Symptoms that mean you need emergency medical attention include:

• Sudden vision changes like blurring or low vision
• Noticeable new or worsening halos or glare around lights
• Sudden, severe eye pain and/or headaches
• Sudden vision loss (either partial or total)

What questions should I ask my doctor?

Some questions to ask your eye specialist include:

• How severe or advanced is my PDS, and has it progressed to PG yet?
• What treatment options do you recommend?
• What kind of side effects should I expect from treatment, and what can I do to manage or limit those side effects?
• Should I make any changes to my usual routine or activities?