Can one eye develop a scotoma and the other eye lose visual acuity in patients with White Dot Syndromes (WDS)?

White Dot Syndromes: Scotoma and Visual Acuity Loss Patterns

Yes, in White Dot Syndromes (WDS), one eye can develop a scotoma while the other eye experiences visual acuity loss, as these conditions can affect both eyes with different manifestations and severity. White Dot Syndromes represent a group of inflammatory retinal conditions that can present with varied patterns of visual impairment across both eyes.

Patterns of Visual Impairment in White Dot Syndromes

Unilateral vs. Bilateral Presentation

• Most White Dot Syndromes initially present with unilateral symptoms, but can progress to bilateral involvement
• Multiple Evanescent White Dot Syndrome (MEWDS) typically presents unilaterally with symptoms including photopsia, scotomas, and decreased vision 1, 2
• Despite seemingly unilateral presentation, functional testing often reveals bilateral involvement, even when symptoms are only reported in one eye 3

Types of Visual Disturbances

1. Scotomas

   • Central scotomas are common in MEWDS and other White Dot Syndromes 1, 2
   • Paracentral scotomas may occur and can be misdiagnosed as optic neuritis 4
   • Enlarged blind spots are frequently observed in affected eyes 3
   • Temporal scotomas have been reported in MEWDS 5

2. Visual Acuity Loss

   • Can range from mild to severe depending on the specific syndrome and location of lesions
   • In MEWDS, visual acuity can decrease significantly (e.g., 20/140) during acute phase 5
   • Punctate Inner Choroidopathy (PIC) can cause acute vision decrease associated with central and paracentral scotomas 6

Diagnostic Approach

Imaging and Testing

• Optical Coherence Tomography (OCT) is essential to detect disruption of the photoreceptor inner/outer segment junction line 3
• OCT-A allows depth-resolved, noninvasive blood flow detection that may identify perfusion loss corresponding to scotomas 4
• Microperimetry is the gold standard for detecting scotomas and fixation patterns 4
• Visual field testing can detect enlarged blind spots and scotomas in both affected and seemingly unaffected fellow eyes 3
• Fluorescein angiography in MEWDS exhibits a characteristic "wreath-like" arrangement of hyperfluorescent lesions 2

Key Findings

• OCT may show disrupted or irregular photoreceptor inner/outer segment junction line in affected eyes 3
• Visual field testing often reveals enlarged blind spots in all affected eyes 3
• Fellow eyes may show subclinical involvement with enlarged blind spots or peripheral visual field defects 3

Management Considerations

Treatment Options

• Most White Dot Syndromes are self-limiting with favorable prognosis for visual recovery within several weeks 1
• Short-term oral corticosteroid therapy may be considered for rapid recovery of vision:
  • One case study showed improvement from 20/140 to 20/25 within one week of starting prednisolone (0.75 mg/kg/day) 5
  • Another case showed good therapeutic effect with corticosteroids for PIC 6

Monitoring and Follow-up

• Regular monocular Amsler grid testing is important to detect changes in scotomas 4
• Follow-up examinations should monitor visual fields to detect progression or resolution 4
• OCT monitoring can track restoration of the photoreceptor outer segments 3

Recovery Patterns

Visual Function Recovery

• Visual acuity typically returns to normal (e.g., 20/20) within weeks to months 5, 3
• The photoreceptor IS/OS line on OCT is usually restored, though focal disruption may persist in some cases 3
• Visual fields often return to normal, but enlarged blind spots may remain in some affected eyes 3
• Electroretinography responses (both full-field and multifocal) typically recover markedly 3

Important Clinical Caveat

Even when White Dot Syndromes appear to affect only one eye clinically, subclinical involvement of the fellow eye is common. In one study, despite unilateral symptoms and visible fundus lesions, photoreceptor dysfunction was bilateral in most cases 3. This explains how one eye might present with a scotoma while the other shows visual acuity loss or different patterns of visual field defects.