White dot Syndromes

Overview

White dot syndromes (WDS) are a group of rare, idiopathic inflammatory eye diseases characterized by the presence of multiple white spots or lesions in the retina, retinal pigment epithelium (RPE), and/or choroid. These conditions typically affect young to middle-aged adults and can present with sudden-onset visual disturbances, such as blurred vision, scotomas (blind spots), or photopsia (flashes of light). The term "white dot syndromes" is not a single disease but an umbrella term for a group of disorders that share similar fundoscopic appearances but have distinct clinical features and prognoses.

Common entities within this group include:

• Multiple Evanescent White Dot Syndrome (MEWDS)

• Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)

• Punctate Inner Choroidopathy (PIC)

• Multifocal Choroiditis and Panuveitis (MCP)

• Birdshot Chorioretinopathy

• Serpiginous Choroiditis

Causes

The exact causes of white dot syndromes remain unclear, but they are believed to involve an autoimmune or inflammatory mechanism. The body’s immune system may mistakenly target components of the retina or choroid following a trigger, such as a viral infection or environmental exposure. Each syndrome within the WDS group may have different triggers or risk factors.

Proposed contributing factors include:

• Viral or bacterial infections: Often reported prior to onset, especially in MEWDS and APMPPE.

• Genetic predisposition: Certain HLA types (e.g., HLA-A29 in birdshot chorioretinopathy) increase susceptibility.

• Autoimmune responses: Dysregulated immune activity is a suspected mechanism, particularly in recurrent or bilateral cases.

Symptoms

Symptoms vary depending on the specific white dot syndrome but generally involve visual disturbances and signs of intraocular inflammation. The symptoms may be unilateral or bilateral and can be acute or progressive in nature.

Common symptoms include:

• Blurred or hazy vision

• Photopsia: Flashes of light, particularly in peripheral vision

• Scotomas: Small blind spots in the central or peripheral field

• Metamorphopsia: Distorted vision (wavy or bent lines)

• Decreased contrast sensitivity and color perception

• Eye pain or discomfort: In some inflammatory forms such as multifocal choroiditis

Diagnosis

Diagnosis of white dot syndromes requires a comprehensive ophthalmologic evaluation, including imaging studies to differentiate among the various syndromes and rule out infectious or neoplastic mimics.

Key diagnostic tools include:

• Fundoscopy: Direct visualization of white dots or lesions in the retina and choroid.

• Fluorescein angiography (FA): Identifies areas of inflammation, leakage, or hypoperfusion.

• Indocyanine green angiography (ICGA): Helpful for visualizing choroidal lesions.

• Optical coherence tomography (OCT): Provides cross-sectional imaging of retinal layers and can reveal inflammation or damage.

• Visual field testing: Detects functional deficits such as scotomas or peripheral vision loss.

• Laboratory testing: May be used to exclude infectious, autoimmune, or systemic inflammatory diseases.

Treatment

Treatment of white dot syndromes depends on the specific diagnosis and severity of inflammation. Many cases are self-limiting and require only observation, while others may need aggressive immunosuppressive therapy.

General treatment strategies include:

• Observation: In mild, self-limiting cases like MEWDS, spontaneous resolution often occurs without treatment.

• Corticosteroids: Oral or periocular corticosteroids may be used in moderate to severe inflammatory cases (e.g., MCP, PIC).

• Immunosuppressive agents: Drugs like azathioprine, mycophenolate mofetil, or cyclosporine are used for chronic, recurrent conditions such as birdshot chorioretinopathy.

• Biologic therapy: Anti-TNF agents and other targeted immunomodulators may be considered in refractory cases.

• Antiviral or antibiotic therapy: Rarely used, but may be needed if an infectious trigger is identified.

Supportive therapies:

• Monitoring for recurrence with regular eye exams

• Low vision support if permanent damage occurs

• Protective eyewear or sunglasses to reduce photophobia

Prognosis

The prognosis for white dot syndromes varies based on the specific subtype, severity of inflammation, and timeliness of treatment.

• MEWDS: Excellent prognosis with full visual recovery in most cases within weeks.

• APMPPE: Generally good prognosis, though some patients may experience mild permanent vision loss.

• PIC and MCP: Variable prognosis; may result in chorioretinal scarring and recurrent flares if not managed appropriately.

• Birdshot chorioretinopathy: Chronic, progressive condition requiring long-term immunosuppression. Prognosis is guarded without treatment.

• Serpiginous choroiditis: Often progressive and recurrent, with risk of significant vision loss over time.

Early diagnosis and appropriate treatment are critical to preserving vision and minimizing long-term complications. Lifelong follow-up may be required in chronic or relapsing forms.