What is the management approach for patients with Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSES) who develop scotomas around the blind spot?

Management of Scotomas Around the Blind Spot in Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSES)

For patients with Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSES) who develop scotomas around the blind spot, regular monitoring with OCT imaging is the recommended approach, with consideration of corticosteroid therapy in cases with rapid progression or associated inflammation.

Clinical Features and Diagnosis

AIBSES is characterized by:

• Unilateral visual field loss in the blind spot area
• Acute onset photopsia ("shimmering lights")
• Few or no optic disc changes on funduscopic examination
• Predominantly affects young adults (20s-30s)
• Often misdiagnosed as optic neuritis due to low awareness 1

Diagnostic Approach

1. Optical Coherence Tomography (OCT):

   • Gold standard for diagnosis 1
   • Reveals marked peripapillary changes in the ellipsoid zone
   • Shows abnormalities in outer retinal microstructure corresponding to areas with scotomas 2

2. Visual Field Testing:

   • Documents enlargement of blind spot
   • May show arcuate scotoma associated with physiological blind spot 2

3. Multifocal Electroretinogram (mfERG):

   • Shows reduced amplitudes in the area of scotoma
   • Can detect subclinical retinal dysfunction even after visual symptoms resolve 3

4. Fluorescein Angiography:

   • Usually normal in classic AIBSES
   • May show vasculitis in atypical cases 4

Management Approach

Monitoring

1. Regular OCT Follow-up:

   • Monitor restoration of outer retinal layers
   • Follow structural changes in the ellipsoid zone and cone outer segment tip line 2

2. Serial Visual Field Testing:

   • Track changes in scotoma size and configuration
   • Use Amsler grid for patient self-monitoring between visits 5

3. Patient Education:

   • Explain the nature of scotomas and photopsia
   • Teach monocular Amsler grid testing to detect changes 6
   • Inform about potential for contralateral eye involvement 7

Treatment Options

1. Observation:

   • Appropriate for mild cases with stable scotomas
   • Many cases show spontaneous improvement over 6-12 months 1

2. Corticosteroid Therapy:

   • Consider for cases with:
     • Rapid progression
     • Associated inflammation/vasculitis
     • Severe symptoms affecting quality of life 4
   • Protocol: Weight-adapted oral prednisolone, gradually tapered over 6-8 weeks 1
   • May support outer retinal reorganization and potentially accelerate recovery 1

3. Vision Rehabilitation Strategies (for persistent scotomas):

   • Teach patients to use preferred retinal locus (PRL) outside the scotoma 5
   • Improve lighting and contrast to enhance remaining vision 5
   • Consider magnification aids if central vision is affected 5

Prognosis

• Most patients show significant improvement or complete resolution of scotomas within 6-12 months 1
• OCT typically shows restoration of outer retinal layers corresponding with visual field improvement 1
• Some patients may have persistent subclinical retinal dysfunction detectable on mfERG despite resolution of symptoms 3
• In rare cases, AIBSES can progress to chronic idiopathic blind spot enlargement (CIBSE) 7

Special Considerations

Atypical Presentations

• AIBSES with retinal vasculitis may respond better to steroid treatment 4
• Cases with bilateral involvement or progression require more aggressive monitoring 7

Differential Diagnosis

• Consider other causes of scotomas around the blind spot:
  • Epiretinal membrane (ERM) and vitreomacular traction (VMT) 6
  • Macular telangiectasia 6
  • Optic disc drusen 5
  • Acute zonal occult outer retinopathy (AZOOR) 7

Monitoring for Complications

• Watch for development of other retinal conditions
• Monitor for potential side effects if corticosteroid therapy is initiated
• Assess for quality of life impact from persistent scotomas

Regular follow-up is essential as AIBSES can be part of a spectrum of outer retinal diseases that may evolve over time, requiring adjustment of management strategies.