What is White Dot Syndromes?
The “white dot syndromes” are a group of eye conditions, called inflammatory chorioretinopathies, that can occur at the deeper part of the retina, a region called the choroid. They appear as many small, separate white spots and are often associated with a prior viral infection. However, we don’t fully understand what causes these conditions.
People usually notice symptoms of these syndromes when they are young and otherwise healthy. They may see flashes of light (photopsia) or floating specks (floaters), struggle with seeing in the dark, or have blurry vision that can lead to loss of vision. These symptoms can come on quickly, be temporary, and not have any long-lasting effects on the vision.
The white dot syndromes have many similarities, including the characteristic white spots on the retina (chorioretinal lesions), as well as other unique traits, and findings during medical tests that help distinguish between them. Some of the commonly known white dot syndromes are: Multiple Evanescent White Dot Syndrome (MEWDS), Acute Retinal Pigment Epitheliopathy (ARPE), Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE), Multifocal Choroiditis and Panuveitis (MCP), Acute Zonal Occult Outer Retinopathy (AZOOR), Birdshot Chorioretinopathy, Serpiginous Choroidopathy, and Punctate Inner Choroidopathy (PIC).
These conditions have been traditionally treated as distinct entities, but some think they could be part of a spectrum of diseases affecting the choroid and retina of the eye.
What Causes White Dot Syndromes?
The cause of the white dot syndromes, a variety of conditions that appear as small, white spots affecting parts of the eye, is still unknown. Some of these conditions seem to be connected with symptoms that usually follow viral infections, suggesting a possible viral or infection-related cause. However, much like in many other autoimmune disorders, it is presumed that an unidentified trigger might start an inflammation or an immune response in the back part of the eye.
White dot syndromes mainly occur in the eye, and aren’t linked with widespread inflammation or autoimmune disorders that affect the whole body. Some subgroups of patients with white dot syndrome, like those with AZOOR (a specific type of white dot syndrome), have shown a higher rate of such conditions.
Birdshot chorioretinopathy, a specific type of white dot syndrome, is strongly related to the presence of the HLA-A29 gene variant. This correlation is so strong that if a patient does not have this gene variant, even when they show typical symptoms, it might suggest that they have another condition and the diagnosis should be reconsidered.
Risk Factors and Frequency for White Dot Syndromes
White dot syndromes usually occur in young, healthy adults under the age of 50, with a few exceptions like birdshot chorioretinopathy and serpiginous choroiditis. Some of these conditions are more often found in females, specifically birdshot chorioretinopathy, MCP, PIC, AZOOR, and MEWDS. Despite these gender differences, white dot syndromes are broadly considered rare, with an annual community-based incidence of 0.45 per 100,000.
Signs and Symptoms of White Dot Syndromes
White Dot Syndrome is a condition that affects the eyes. Its main symptoms include sudden changes in vision, such as loss of visual field or blind spots, light flashes, blurred vision, and specks that float in your field of vision, commonly known as floaters. Some patients might also mention symptoms similar to a viral infection before the onset of the eye symptoms. A key sign of this condition is the appearance of white or cream-colored spots in the retina (back of the eye). These spots are different in shape and spread, and help in telling White Dot Syndrome apart from other conditions.
Some types of White Dot Syndrome affect one eye (like MEWDS), while others affect both (like APMPPE, Birdshot Chorioretinopathy, and MCP). Inflammation of the front part of the eye, also known as the anterior chamber, is uncommon, except in the case of MCP. Lastly, vitritis, which is inflammation of the jelly-like substance in your eye, can be seen in several types of White Dot Syndrome. It’s most consistently seen in Birdshot Chorioretinopathy.
Testing for White Dot Syndromes
When a person might have white dot syndrome, a condition that affects the eyes, certain tests can help doctors rule out other similar conditions. The most common tests include blood tests for syphilis, which is recommended for all patients, and screening for tuberculosis, which is recommended for people who have been exposed to tuberculosis or are at risk for it.
Sometimes, doctors might also check for a substance called angiotensin-converting enzyme (ACE) in the patient’s blood or take X-rays of the patient’s chest to look for signs of sarcoidosis, a disease that can affect various body organs. However, these tests are not always reliable.
There are also several tests doctors can use to examine patient’s eyes and help them figure out which type of white dot syndrome the patient has. These can include fluorescein angiography, where a fluorescent dye is injected into the bloodstream to highlight the blood vessels in the back of the eye, and optical coherence tomography, which uses light waves to take cross-section pictures of the retina. Other possible tests include visual field testing to measure peripheral vision, indocyanine green angiography, a similar procedure to fluorescein angiography but using a different dye, fundus autofluorescence to evaluate the health of the retina, and electroretinography to measure the electrical responses of cells in the eyes.
Treatment Options for White Dot Syndromes
White dot syndromes are a group of diseases that affect the eye causing white dots to form, often on the retina. Many of these conditions are harmless and go away on their own, so no treatment is needed. However, some white dot syndromes like MCP, serpiginous choroiditis, and birdshot chorioretinopathy can lead to serious vision problems if left untreated.
For these more serious conditions, treatment usually begins with corticosteroids, which are drugs that reduce inflammation. Depending on the case, these could be applied directly to the eye or given as a general treatment for the whole body. Doctors aim to then transition to treatments that can reduce inflammation without the side effects of steroids. These are known as immunotherapies, and they work by calming down the body’s immune system to stop it from causing inflammation.
There are many different drugs that can be used as immunotherapies, including traditional ones like methotrexate, mycophenolate mofetil, azathioprine, and cyclosporine, as well as newer ones, called biologics, such as adalimumab and infliximab. In severe cases, where the condition threatens the person’s vision, strong drugs known as cytotoxic agents can be used. These include cyclophosphamide and chlorambucil.
Alongside these treatments, it may sometimes be necessary to manage complications which can occur with white dot syndromes, such as cystoid macular edema (CME – a swelling in the center of the retina) and choroidal neovascularization (CNV – the growth of new blood vessels in the eye). Treatments for these complications can include immunosuppression (calming down the immune system), localized ocular therapies (treatments that are applied directly to the eye), anti-VEGF agents (drugs which block the growth of new blood vessels), laser photocoagulation therapy (using a laser to treat the eye), or photodynamic therapy (a type of light therapy).
What else can White Dot Syndromes be?
White dot syndromes can be caused by both infectious and non-infectious conditions. When doctors are trying to figure out what is causing white dot syndromes, they have to consider several potential reasons. Some of these are non-infectious processes, like:
- Sarcoidosis
- Vogt-Koyanagi-Harada (VKH) syndrome
- Sympathetic ophthalmia
- Intraocular lymphoma
They also look at infectious entities, such as:
- Syphilis
- Primary ocular histoplasmosis syndrome (POHS)
- Tuberculosis
- Diffuse unilateral subacute neuroretinitis (DUSN)
All these conditions have to be considered while diagnosing white dot syndrome.
What to expect with White Dot Syndromes
The outlook for most conditions classified as ‘white dot syndromes’ – which include illnesses like ARPE, MEWDS, APMPPE, and AZOOR – is typically good. These conditions are often self-limiting and progress on their own, with most patients eventually regaining their original or near-original vision. However, in a small group of these patients, certain visual issues such as ‘scotoma’ (a blind spot in the visual field) and ‘photopsia’ (the sensation of seeing flashes of light) may remain.
However, there are some forms of white dot syndromes – such as MCP, birdshot chorioretinopathy, and serpiginous choroiditis – that have a more sustained and progressively worsening course, which could result in moderate to severe loss of vision.
For these reasons, it is extremely important to identify and manage these conditions at an early stage to prevent lasting visual impairment.
Possible Complications When Diagnosed with White Dot Syndromes
It is unusual for a person suffering from white dot syndromes to experience complications that affect the movements of the eyes. Some patients may experience symptoms similar to those of a short-term viral illness. In APMPPE, a type of white dot syndrome, these symptoms could include signs of inflammation of the membranes surrounding the brain and spinal cord.
In certain cases, white dot syndromes are linked to autoimmune diseases, where the body’s immune system attacks its own cells. If a person shows any signs or symptoms that indicate an autoimmune condition, further evaluation is needed.
Certain treatments require careful monitoring due to potential complications. For example, systemic immunotherapy, a type of treatment that uses the body’s immune system to fight diseases, should be closely monitored by a specialist familiar with its use.
Eye-related complications linked to white dot syndromes could include issues inherent to chorioretinopathy, a type of eye disorder. These issues might involve cystoid macular edema (CME – fluid-filled cyst-like areas in the retina) and/or choroidal neovascularization (CNV – the growth of new blood vessels in the eye).
Choroidal neovascular membranes, a type of CNV is a common issue seen in patients with PIC, a particular type of white dot syndrome. There are estimates that it affects 40% to 75% of cases.
Additional complications related to the use of certain types of steroid medications (topical, periocular, and intravitreal corticosteroids) include early cataract formation and increased pressure in the eye. There might also be complications related to the management of the condition through procedures or surgeries.
- Complications impacting eye movements
- Symptoms similar to a viral illness
- Indicators of an autoimmune condition
- Potential complications from systemic immunotherapy
- Eye disorders like cystoid macular edema (CME) and/or choroidal neovascularization (CNV)
- Complications from certain types of steroid medications
- Early cataract formation and increased eye pressure
- Complications related to procedures or surgeries
Preventing White Dot Syndromes
As mentioned earlier, most “white dot syndromes” — a term used to describe a group of rare eye conditions — can resolve on their own, so usually no treatment is needed. However, your doctor may prefer to closely watch your condition for about a month. This can be done using a type of eye exam called a “dilated funduscopic examination”. In this exam, eye drops are used to widen (dilate) your pupils to allow a better view of the back of your eyes. This way, the progress of your condition can be tracked effectively.
