White Dot Syndromes - An Overview

Introduction

WDS is a group of heterogeneous inflammatory chorioretinopathy disorders characterized by the formation of white spots on the fundus and inner surface of the eye's retina. Symptoms include blurring of vision, visual field loss (damage to visual pathway), floaters (dark spots in eyes), and photopsia (flickering of light and presence of perceived flashes of lights). Jampol L.M. and colleagues were the first to discover WDS. The onset of the disease is acute and self-limiting. In addition, WDS is associated with a female predilection.

What Is the Classification of White Dot Syndromes?

The diseases that comprise WDS include acute posterior multifocal placoid pigment epitheliopathy (APMPPE), serpiginous choroiditis, multiple evanescent white dot syndrome (MEWDS), multifocal choroiditis and panuveitis (MCP), punctate inner choroidopathy (PIC), diffuse subretinal fibrosis (DSF), presumed ocular histoplasmosis syndrome (POHS) and birdshot retinochoroidopathy. The prognosis of the disease is excellent. Recurrences are rarely associated with WDS.

Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE):

• APMPPE is seen in young adults.

• There is a painless bilateral loss of vision.

• Symptoms include fever, myalgia (muscle pain), headache, and malaise. Fundus examination shows flat yellow-white placoid (fish scale-like) lesions nearly 0.5 mm in size.

Serpiginous Choroiditis:

• Serpiginous choroiditis is also called geographic choroidopathy.

• It is present in middle-aged males.

• Unilateral or bilateral loss of vision.

• Photopsias.

• Scotomata (defined as a decrease in vision and formation of blind spots).

Multiple Evanescent White Dot Syndrome (MEWDS):

• MEWDS is seen in young females.

• It is associated with a viral prodrome (an early symptom indicating an onset of disease or illness).

• There is acute, painless, unilateral loss of vision.

• Photopsias.

• Scotomata.

Multifocal Choroiditis and Panuveitis (MCP):

• MCP is a common disease characterized by multifocal chorioretinal lesions.

• Characterized by vitreous inflammation.

• It is usually seen in myopic (short-sightedness) females around the second and sixth decades of life.

• Patients have blurred vision, photopsia, and scotoma.

• Bilateral involvement is seen.

Birdshot Retinochoroidopathy:

• It is also called vitiliginous choroiditis.

• This lesion is seen in females around the fourth to fifth decade of life.

• There is painless gradual blurring of vision, floaters, and loss of color vision.

• The disorder is characterized by multiple depigmented yellow-white patches around the fundus.

• Lesions emerge from the optic nerve and follow the larger choroidal vessels.

• It is called birdshot retinochoroidopathy because the pattern is similar to the shotgun scatter of birdshot.

• These signs, such as vitritis (inflammation of the vitreous body), optic disc edema, and cystoid macular edema, can also be seen.

Presumed Ocular Histoplasmosis Syndrome (POHS):

• POHS is seen in adults in the fourth decade of life.

• It is seen equally in males and females.

• Patients can be asymptomatic or may be present with reduced vision and a central scotoma.

• The etiology is thought to be due to H. capsulatum.

What Are the Causes of White Dot Syndrome?

• The exact etiology is unknown.

• History of viral infections, it has been postulated that the virus enters the retina, and infection may spread from one photoreceptor to another.

• Autoimmune diseases.

What Are the Symptoms Associated With White Dot Syndromes?

• Painless decrease in vision.

• Photopsia (anomalies in the vision and flickering lights).

• Dyschromatopsia (deficit in color vision).

• Temporal or paracentral scotoma (complete loss of vision).

What Is the Diagnosis of White Dot Syndromes?

1. Fundus Autofluorescence (FAF) - FAF is the rapid and noninvasive method to diagnose WDS. It is the most sensitive test which shows hyper autofluorescence lesions.

2. Optical Coherence Tomography (OCT) - OCT also helps diagnose WDS by detecting the discontinuities in the retina's inner and outer segments of the retina.

3. Visual Field - An enlarged blind spot is mainly seen in the visual field. Also, central or paracentral scotoma is seen when there is the formation of blind spots in the line of vision. Acute idiopathic blind spot enlargement syndrome may be seen in the disease process.

4. Indocyanine Green Angiography (IGA) - IGA helps to detect the disease by showing hypocyanescent spots and plays an important role in diagnosing the disorder.

5. Electroretinogram - Electroretinogram shows the reduced a-wave amplitude, and early receptor potential may show prolonged duration.

6. Electrooculogram - A decrease in Arden's ratio is a diagnostic sign in WDS. Visual-evoked responses represent a reversible decrease in amplitude and may prolong the latency period.

What Is the Differential Diagnosis Associated With White Dot Syndromes?

Differential diagnoses of WDS include all of the following:

• Sarcoidosis (granulomas in lungs, heart, and eyes).

• Vogt-Koyanagi-Harada syndrome (affects eyes, ears, nervous system, and skin).

• Sympathetic ophthalmia (inflammation in the eye because of injury or surgery).

• Intraocular lymphoma (tumor originates outside the central nervous system and can metastasize to the eyes).

• Syphilis (a sexually transmitted disease that occurs because of bacterial infection).

• Primary ocular histoplasmosis syndrome (can lead to vision loss).

• Tuberculosis (bacterial infection mainly affecting the lungs).

• Diffuse unilateral subacute neuroretinitis (leads to severe visual impairment and blindness).

What Is the Management of White Dot Syndromes?

• WDS is self-limiting, and commonly no treatment is required for this disease entity.

• Treatment consists of the use of systemic immunosuppressive therapy to treat WDS.

• Coordinated teamwork between healthcare professionals, ophthalmologists and rheumatologists, nursing staff, and the patient's family clinician is required for active intervention to diagnose and manage the condition.

• Local or systemic corticosteroids are used in the treatment of WDS.

• Traditional immunotherapies such as Methotrexate, Mycophenolate mofetil, Azathioprine, and Cyclosporine can be used to treat the condition.

• Biological agents can also be used, including anti-tumor necrosis factor medications such as Adalimumab and Infliximab.

• Certain vision-threatening conditions involving serpiginous choroiditis are treated using cytotoxic agents such as Cyclophosphamide and Chlorambucil.

• Other ocular complications such as cystoid macular edema (CME) and choroidal neovascularization (CNV) can be managed by immunosuppressives or other localized ocular therapies, including anti-vascular endothelial growth factor, laser photocoagulation therapy, or photodynamic therapy.

What Are the Complications Associated With White Dot Syndrome?

• Chorioretinopathy (fluid accumulation under the retina and impaired vision).

• CME (painless involvement of the macula and causes swelling).

• CNV (growth of new blood vessels and major cause of vision loss).

Conclusion

WDS includes disorders affecting the retina, retinal pigment epithelium, and choroid. Interprofessional team members are required to treat the condition. WDS presents diagnostic and therapeutic challenges both to the clinician & the scientist. For successfully managing the case of WDS, it is important to go for careful observation of signs, documentation of findings, long follow-up of cases & appropriate treatment of reactivation with steroids and immunosuppressive agents.