AZOOR Scotoma Patterns
In Acute Zonal Occult Outer Retinopathy (AZOOR), scotomas do not typically appear in a star pattern around the fixation point. Rather, AZOOR presents with various scotoma patterns that need to be properly characterized for diagnosis and management.
Characteristics of Scotomas in AZOOR
AZOOR is characterized by the following scotoma patterns:
- Paracentral scotomas that may be unilateral or bilateral 1
- Scotomas that correspond to areas of outer retinal layer perfusion loss, detectable on OCT-A even when fluorescein angiography appears normal 1
- Visual field defects that do not typically form a star pattern around fixation
Diagnostic Approach for AZOOR
Recommended Imaging Studies
- Microperimetry: Gold standard for detecting scotomas and fixation patterns, especially with unstable fixation 1
- Standard OCT: Initial test to rule out macular pathology 1
- OCT-A: For detecting perfusion loss in the outer retinal layer that may correspond to scotomas 1
- Wide-field imaging: For peripheral scotoma detection 1
- Amsler Grid Testing: For periodic monitoring of central vision changes 1
Differential Diagnosis
AZOOR must be differentiated from other conditions with similar presentations:
- Central serous chorioretinopathy
- Multiple evanescent white dot syndrome
- Optic neuritis (common misdiagnosis when AZOOR presents with paracentral scotomas)
- Epiretinal Membrane (ERM) and Vitreomacular Traction (VMT) 1
Impact of Scotomas on Visual Function
Scotoma patterns significantly impact visual function:
- Scotoma patterns that limit horizontal span for reading may reduce reading fluency and ability to use magnification 2
- Patients with foveal-sparing scotoma patterns (encircling the fovea) have limited horizontal span for reading 2
- Even with magnification, reading with non-foveal retinal fixation does not restore normal continuous print reading speed 2
Management Considerations
Vision Rehabilitation
- Vision rehabilitation is essential for patients with central or paracentral scotomas 1
- Magnification devices can optimize the use of remaining vision 1
- Training interventions may include:
- Device training
- Oculomotor function training
- Perceptual training
- Structured reading practice
- Training fixation with a preferred retinal locus (PRL) 2
Treatment Options
- Treating underlying retinal disease is essential 1
- Some cases have shown reduction in scotoma size with corticosteroid treatment 1
- Regular monitoring with monocular Amsler grid testing is important to detect changes 1
Important Caveats
Misdiagnosis Risk: AZOOR is commonly misdiagnosed as optic neuritis when it presents with paracentral scotomas 1
Fixation Patterns: In progressive central scotomas, patients tend to develop a preferred retinal locus (PRL) along the same meridian as the scotoma progresses 3
Prism Spectacles: Prism spectacles for fixation relocation are not recommended based on evidence showing no significant benefit for patients with macular degeneration 2
Reading Challenges: Multiple factors contribute to decreased reading fluency with scotomas, including visual span limitations, perceptual span limitations, oculomotor control issues, and slower visual processing 2