What is Posner-Schlossman Syndrome?
In 1948, two doctors, Posner and Schlossman, identified a distinctive type of glaucoma in their patients. This unique type of glaucoma involved sudden pressure increases in one eye and didn’t close the front angles of the eye. This series of symptoms is known today as Posner-Schlossman syndrome (PSS), a rare disease also called the glaucomatocyclitic crisis.
PSS specifically targets one eye and is marked by repeated bouts of inflammation and increased pressure within the eye. Unlike other forms of glaucoma, PSS often involves mild to moderate inflammation in the front chamber of the eye, which is why it’s categorized as inflammatory glaucoma.
The raised pressure in the eye during episodes of PSS could eventually lead to chronic glaucoma. Initial attacks may go unnoticed due to the mild inflammation. Due to the sudden eye pressure increase, it’s easy to mistake PSS for acute angle-closure glaucoma, especially when the inflammatory reaction in eye’s front chamber is overlooked.
During an episode, patients often experience sudden, severe eye pain, redness, blurry vision, and light halos. In between episodes, they may feel a bit of discomfort or grittiness in their eye. However, symptoms usually only trouble one eye at a time.
It’s difficult to establish how many people are affected by PSS, and it seems to target individuals between 20 and 50 years old the most. The symptoms come and go, making it hard to determine the exact number of cases.
To diagnose PSS, thorough eye examination is carried out. Eye doctors will measure internal eye pressure, check for inflammation, and rule out other potential causes of glaucoma. They may also conduct imaging and other tests to examine the eye’s drainage angle and exclude other types of glaucoma.
Most people with PSS can expect a positive outlook. Quick treatment often prevents vision loss, and episodes of increased eye pressure usually alleviate on their own or with medication. However, repeated episodes can cause permanent vision loss if not managed well, so continual monitoring is vital.
Patients’ symptoms vary – they can occur often with short breaks in-between or less frequently with more extended breaks. Regardless, the symptoms usually go away on their own within days or weeks, even without treatment.
The goal of treating PSS is to control eye pressure and reduce inflammation during episodes. Often, patients are prescribed oral medications and anti-inflammatory eye drops. In some cases, they might need more invasive treatments like laser therapy or surgery.
PSS’s causes and risk factors are not entirely understood, so more research has to be done. Investigating the disease’s genetic and immune system-related triggers may offer possible preventative measures. Advanced treatments and diagnostic tools may also prove beneficial for early diagnosis and treatment of PSS.
This brief discussion aims to provide an overview of PSS’s diagnosis and treatment.
What Causes Posner-Schlossman Syndrome?
Though experts aren’t entirely sure why Posner-Schlossman Syndrome (PSS) happens, several potential causes are suggested. Some theories posit that it could relate to an autoimmune response, where the body’s immune system attacks its own cells, or an allergy. Interestingly, records from as far back as 1935 mentioned patients with similar symptoms to PSS, which they called “glaucoma allergicum.”
Another theory suggested by Posner and Schlossman is that PSS could be a result of issues with the autonomic nervous system – the system responsible for controlling involuntary bodily functions such as heartbeat and digestion. Other researchers thought that abnormalities in blood vessels or development could play a role.
The idea that infections could be causing PSS seems to be widely accepted. Evidence suggests that infections from cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), or even the bacteria Helicobacter pylori could be responsible.
The theory that CMV might be causing PSS is backed up by several studies. Some researchers found that treatment with antiviral drugs that target CMV was successful in treating PSS. The theory holds weight because they could detect both antibodies for CMV, which the body makes to fight the virus, and CMV DNA, the virus’s genetic material, in the fluid of the eye during episodes of PSS and weeks afterward.
In one study, it was found that when patients with anterior uveitis, an inflammation of the middle layer of the eye, didn’t respond well to steroid therapy, they often also had a viral infection. In fact, 67% of those patients tested positive for CMV, HSV, VSV, or rubella. It was also noticed that if the patients had high eye pressure, they were more likely to test positive for CMV.
Medications like ganciclovir and valganciclovir, which target the infecting virus, have shown to be effective. It’s also been noted that using ganciclovir inside the eye has proven successful, supporting the idea that PSS is caused by a virus. However, most patients experienced a relapse once the antiviral treatment stopped.
Risk Factors and Frequency for Posner-Schlossman Syndrome
PSS, or Presumed Scleritis Syndrome, is a condition that typically affects adults, most often males, and the risk for developing PSS tends to increase with age. Studies show people between the ages of 20 to 50 are most often diagnosed. However, the age of onset can differ depending on the region, with people in Europe often developing it in their 20s and 30s, whilst people in Asia commonly develop it later, around their 30s to 50s.
Research has documented the rate of PSS to be between 1.7% to 4.3% of all uveitis diagnoses in Japan and Singapore. In glaucoma cases linked to uveitis, the rate varies from 6.5% to 11.4%. According to a Finnish study, the condition is relatively rare with an incidence of 0.4 and prevalence of 1.9 in 100,000 people. However, data from Wenzhou, China, presents a higher 10-year cumulative incidence – 39.5 in 100,000 people, with an average annual incidence of 3.91 in 100,000 people.
Interestingly, it’s been observed that more new cases seem to occur in the spring season, indicating the possibility of a seasonal trend with PSS.
- PSS usually affects adults, especially males.
- Typically, people between the ages of 20 to 50 are diagnosed with this condition.
- The age when PSS develops can vary depending on the region
- In terms of uveitis diagnoses, the rate of PSS is between 1.7% to 4.3% in Japan and Singapore.
- The rate of glaucoma linked to uveitis varies from 6.5% to 11.4%.
- A study from Finland showed an incidence of 0.4 and prevalence of 1.9 in 100,000 people, making the condition relatively rare.
- However, data from Wenzhou, China showed a higher 10-year cumulative incidence – 39.5 in 100,000 people with an average annual incidence of 3.91 in 100,000.
- Interestingly, more new cases seem to appear in the spring, hinting at a possible seasonal trend with PSS.
Signs and Symptoms of Posner-Schlossman Syndrome
Patients with Posner-Schlossman Syndrome (PSS), also known as glaucomatocyclitic crisis, might not show any symptoms, or they could experience eye pain, discomfort, or blurred vision. If present, these symptoms can recur. Some people might see halos around lights, which indicates swelling in the surface of their eyes due to an increase in inner eye pressure (IOP). Typically, the same eye is affected in multiple episodes, but in some cases, both eyes might be affected. The frequency of these episodes can differ from patient to patient, with some experiencing multiple episodes in a month and others having fewer. In-between these episodes, the patient usually experiences no symptoms.
An eye exam is crucial for diagnosing PSS. During an episode, the vision can vary from normal to extremely poor, with high IOP levels as high as 40 mmHg or more. The preferred method for measuring IOP is Goldmann applanation tonometry. Gonioscopy might show an open eye angle. In some cases, particularly in people of Asian descent, the eye angle might be narrow or closed. Even with active inflammation, the usual signs of angle abnormalities are not typically seen in PSS. However, there have been instances of unusual signs like an anteriorly displaced line in the eye called Schwalbe’s line. These are not usually considered as defining signs of PSS.
In most cases, signs of inflammation inside the eye surface are seen after IOP has been high for days to weeks. Observations made with a slit-lamp microscope may show an inflammation characterized by small, non-granular deposits on the cornea. If the patient is also infected with cytomegalovirus (CMV), there may be associated symptoms like coin-like opacities on the cornea and inflammation of the inner surface of the cornea.
- History of recurring acute episodes
- High IOP with fewer anterior chamber cells than expected
- One or two distinct deposits over the lower inner layer of the cornea
Recent studies indicate that PSS can result in a reduced number of cells on the surface of the cornea. Several risk factors can contribute to this reduction, including a longer disease duration, increased aqueous levels of a type of protein called ‘interleukin-10’, high levels of retinal nerve fibre layer thinning and glaucomatous damage, and elevated levels of Cytomegalovirus DNA in the front part of the eye.
Findings related to the optic nerve, which connects the eye to the brain, vary significantly in PSS. In many cases, the optic disc looks normal during an acute attack. However, in the long term, with repeated high IOP, the optic nerve might get permanently damaged, leading to an open-angle glaucoma. Other clinical signs might include iris atrophy, caused due to repeated or prolonged episodes. A condition called uveitic cataract might occur after a long duration of inner eye inflammation. However, another condition named ‘posterior synechiae’ is not usually associated with PSS.
Testing for Posner-Schlossman Syndrome
To figure out whether you have Posner-Schlossman Syndrome (PSS), a type of eye condition, a doctor might analyze a sample of your eye fluid (aqueous humor) to look for viral DNA. They essentially test for common viruses like cytomegalovirus (CMV), herpes simplex virus (HSV), and varicella-zoster virus (VZV). They may also test your blood for these viruses. Knowing which virus is present helps in planning the right treatment.
Your doctor may also perform central visual field testing to check for a pattern of visual field loss typical of glaucoma, an eye condition that can damage your optic nerve. This test might be referred to as “Humphrey visual field, 24-2 or 30-2”. They may also take special pictures of your optic disc, a circular area at the back of your eye where the optic nerve connects, to check for signs of glaucoma and monitor its progress over time.
During an acute episode of PSS, your doctor may perform iris angiography, a test that uses dye and special x-rays to see the blood vessels in your eye. This can show areas of blockage, congestion, and leakage in these vessels. Another test, scanning laser Doppler flowmetry, can show if there’s decreased blood flow to the optic nerve during an acute attack.
Optical coherence tomography (OCT) and OCT angiography (OCTA) are imaging tests that provide detailed pictures of your optic nerve, the nerve fibers in your retina (the light-sensitive layer at the back of your eye), and the tiny blood vessels around your optic nerve. If these tests show a decrease, it might suggest permanent damage due to glaucoma.
The test results of a 45-year-old male patient diagnosed with left eye PSS showed a significant loss of nerve cells and fibers in the retina and optic nerve. The optic nerve in his right eye was normal. A follow-up OCT test nine years after his initial diagnosis showed ongoing damage. The rate of nerve cell and fiber loss over this period was quite significant. His treatment during this time included eye drops containing steroids, and non-steroidal medicine (Nepafenac) during flare-ups of inflammation, as well as medication to lower eye pressure.
In patients with PSS linked to a group of proteins called “endothelins,” an OCT scan of the cornea (the eye’s outermost layer) might portray an irregular and highly reflective cell layer. A detailed microscopic examination of this layer could reveal large cells that resemble an owl’s eye. These “owl eye” cells are believed to be corneal cells infected by the CMV virus which contains certain structures within the cell nucleus.
Treatment Options for Posner-Schlossman Syndrome
The aim of treating Posner Schlossman Syndrome (PSS) is to reduce eye pressure and inflammation. New treatments use an antiviral treatment to target the infecting virus. This can be done with both medical treatments and surgical methods.
In medical treatments, the first tactic is to use medications routinely used for treating glaucoma to quickly bring down the eye pressure during acute attacks. These medications can be administered topically (as eye drops), or sometimes orally. If the eye pressure is brought back to normal with these medications, they can be stopped, especially if the patient’s risk of developing other eye complications is low. We should avoid one type of medication called pilocarpine because there’s a possibility it might make some conditions worse.
To control inflammation in the eye, eye drops containing steroids like prednisolone or dexamethasone can be used. As an alternative, we can also use other types of anti-inflammatory medications, both as oral drugs and eye drops. Regular patient check-ups are needed to monitor eye pressure, especially during an acute attack. Depending on the severity and progression of the condition, the frequency of patient visits can be adjusted.
If the treatment doesn’t seem to be improving the condition or if the patient experiences multiple repeated episodes, the presence of a certain virus (CMV) in the anterior chamber of the eye should be examined. If the virus is detected, treatment with a specific antiviral drug should be considered.
There is evidence that treating this specific type of viral infection can improve the control of PSS. Several antiviral medications have been used and have shown beneficial effects. However, it’s noted that this treatment didn’t stop the occurrence of future episodes completely.
Although the oral antiviral treatment showed promising results, it was found that the recurrence rate after stopping this medication was quite high. This is attributed to the nature of the medication as it stalls the virus instead of killing it. On top of this, the immunity of the eye prevents total eradication of the virus.
In the event medical treatment is not successful, surgical techniques are used to reduce eye pressure. This includes trabeculectomy, a procedure that improves the flow of fluid in the eye to relieve pressure. However, a potential risk is that pre-existing inflammation in the eye might lead to scarring post-surgery.
Different techniques have been practiced to manage eye pressure, one of which includes a procedure that infuses medication into the eye during the trabeculectomy. This has been shown to reduce inflammation and improve the PSS condition.
Apart from these, there are other surgical techniques that can be deployed to manage the condition. For example: if the patient develops cataracts, surgery is required to remove them. If the disease results in damage to the cornea (the clear surface of the eye), other operations like penetrating keratoplasty or Descemet’s stripping automated endothelial keratoplasty can be considered. Before any of these surgical interventions, it’s important to make sure that the inflammation is well-managed.
Overall, managing PSS may involve a combination of medical and surgical therapies to reduce eye pressure and control inflammation. Regular follow ups are necessary in order to adjust treatments as needed and promptly handle any complications or recurrences.
What else can Posner-Schlossman Syndrome be?
It’s really important to identify the many conditions that can be confused for PSS (Posner-Schlossman Syndrome), because they can affect the treatment and how well a patient might recover. Here are the most common ones:
- Both acute and chronic forms of ACG (Angle-closure Glaucoma)
- Ocular Hypertension, which is when the pressure in your eyes is higher than normal
- POAG or Primary Open-Angle Glaucoma
- Uveitic Glaucoma, which is glaucoma caused by inflammation in the eyes
- Fuchs heterochromic iridocyclitis, an unusual type of chronic iris inflammation
- Herpetic iridocyclitis, which is inflammation of the iris caused by a herpes virus
- Other types of viral uveitis, which is inflammation inside the eye
Doctors need to understand that PSS is different from ACG, which usually comes with a sudden rise in eye pressure, redness, and inflammation. In fact, a surgery that’s used for ACG was wrongly used on a PSS patient because of this confusion. But you can distinguish ACG from PSS because ACG often comes with narrow or closed angles in your eye, severe redness and pain in the eye, a fixed and dilated pupil, feeling sick and vomiting, and ciliary processes binding around the iris formation.
On the other hand, someone with POAG is likely to be older, perhaps has a family history of the condition, and doesn’t have signs of inflammation in their eyes. Pigmentary glaucoma and pseudoexfoliation glaucoma can also cause spikes in eye pressure, but these diseases have their own unique signs and symptoms.
Similarly, uveitic glaucomas are an important group of conditions that resemble PSS. These cases of glaucoma are usually due to more severe inflammation inside the eye. However, you can tell the difference between Fuchs heterochromic iridocyclitis and PSS, because the first one often has symptoms like different colored eyes, abnormal blood vessels in the eye, small widespread lumps in the cornea, and cataracts that occur at the back of the lens in the eye.
It’s good to know that uveitic glaucoma may be caused by a virus, like the ones that cause herpes. Several signs can differentiate uveitic glaucoma from PSS, such as different degrees of iris loss, more severe inflammation in the front chamber of the eye, and a difference in the level of increased eye pressure.
Going to the doctor and examining the fluid inside the eye might be necessary when the diagnosis is unclear. Understand that a patient may have more than one virus at the same time. Some reports have shown that one eye can have CMV-positive PSS while the other eye has HSV-positive keratouveitis.
In addition, HSV may show other different signs like corneal inflammation with clouding and swelling of the cornea leading to scarring, new blood vessels, and loss of sensation. VZV (Varicella zoster virus), on the other hand, can show up as a skin rash and blisters, sometimes occurring on the nose and forehead. The so-called “Hutchinson’s sign” is a strong signal of eye involvement by VZV, also seen in states of reduced immune response.
What to expect with Posner-Schlossman Syndrome
Over time, some patients have been found to develop significant damage to the optic nerve, resulting in changes to their field of vision and loss of nerve cells. This damage is caused by a prolonged increase in intraocular pressure (IOP), which is the pressure inside the eye. This condition often resembles a disease called glaucoma, and it’s referred to as secondary glaucoma. There has been extensive research into this link with glaucoma.
In one study, almost half of the patients already had glaucoma at their first appointment. Because the inflammation of the eye causes only mild symptoms, patients often aren’t aware of the harmful long-term increase in IOP and the resulting damage to the optic nerve. So, in cases where there’s significant damage, it’s recommended to continue using eye drops to lower the eye pressure even between acute attacks.
Patients in this category should be treated to prevent further problems. According to one study, over a quarter of PSS patients developed glaucoma. Researchers have studied the factors that could predict the development of glaucoma. Among these factors, the total duration of the disease was found to predict progression to glaucoma, while the age of onset and number of attacks were not significant factors.
A recent review of 19 studies involving a total of 1173 PSS patients revealed that glaucoma occurred in 20% of the patients. The risk factors identified in these patients included older age, a longer disease duration, and the condition affecting both eyes. The gender of the patient and the IOP during acute phases were not found to significantly influence the development of glaucoma. Even though the increases in IOP in PSS patients are typically temporary, glaucoma could develop more readily in cases involving recurrent acute IOP spikes, high levels of inflammation, chronic high IOP, impaired function of the trabecular meshwork (which helps drain the eye), and long-term use of steroids.
Possible Complications When Diagnosed with Posner-Schlossman Syndrome
PSS was once thought to be harmless, but it can actually lead to serious eye problems. Some patients could develop a disease called GON. Those who have a larger difference between the cup and the disc in their eye, damage to the layer of cells at the back of their eye, or thinning in a part of the retina, are considered at risk. For these patients, using eye drops that lower the pressure in the eye can prevent illness. If the eye pressure keeps being high and the damage to the eye nerve gets worse, they may need to have surgery.
PSS might also cause Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) and a condition called optic atrophy where the optic nerve deteriorates. Patients diagnosed with PSS and factors that put them at risk for NAION and optic atrophy, like a small cup-to-disc ratio, should also use eye-drops that lower eye pressure.
Eye complications related to PSS can also impact the cornea. Studies have found a decrease in the number of cells in the inner layer of the cornea in eyes with a form of PSS caused by the CMV virus. At later stages, significant loss of these cells would result into dysfunctional cornea following recurring disease. High eye pressure could also cause swelling and cell loss in the cornea surface. Endotheliitis, inflammation of the inner layer of the cornea, is another aspect seen in PSS related to CMV. Our bodies’ immune response to CMV infection in parts of the eye can cause this. PSS can also cause iris atrophy and cataracts.
Common Eye Problems from PSS:
- Progression to GON
- Nonarteritic Anterior Ischemic Optic Neuropathy (NAION)
- Optic Atrophy
- Corneal cell count reduction
- Endotheliitis
- Iris Atrophy
- Cataracts
Preventing Posner-Schlossman Syndrome
To promptly recognize Posner-Schlossman Syndrome (PSS), a rare eye condition, doctors need to be very attentive. If one eye has significantly higher intraocular pressure (IOP, or eye pressure) than usual, even though there isn’t much inflammation and the front part of the eye (anterior chamber angle) is normal, doctors may suspect PSS. It’s very important for the patient to understand the condition to avoid long periods of high eye pressure. Continuous periods of high pressure can lead to complications if not treated.
Patients need to be aware that PSS can come and go, and they should contact an eye doctor if they notice symptoms like slight discomfort or pain in the eye, or blurred vision. These symptoms could indicate a relapse, or return, of the condition after a period of being symptom-free. Because some flare-ups might not be noticeable due to the mild inflammation of the eye (uveitis), it is vital to keep all clinic appointments and avoid any delays in seeing your doctor, particularly if you’re at risk of developing complications such as Glaucomatous Optic Neuropathy (GON), Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION), and decreased blood supply resulting in damaged optic nerves (ischemic optic atrophy).
Doctors should discuss preventive treatment options with at-risk patients, and if needed, discuss the option of surgical treatment for PSS.
