Is peripheral vision loss a symptom of neuromyelitis optic spectrum disorder (NMOSD)?

Peripheral Vision Loss in Neuromyelitis Optica Spectrum Disorder

Yes, peripheral vision loss can occur in NMOSD, but it is atypical and serves as a critical red flag distinguishing NMOSD from MS-related optic neuritis—altitudinal and peripheral visual field defects strongly suggest NMOSD rather than MS and mandate immediate investigation for aquaporin-4 antibodies. 1

Visual Field Patterns That Distinguish NMOSD from MS

Typical MS-Related Optic Neuritis Pattern

• Central scotomas are the hallmark of MS-related optic neuritis, representing damage to the papillomacular bundle with characteristic red-green color desaturation 1
• Central visual field defects dominate the clinical picture in MS 2

NMOSD-Specific Atypical Patterns

• Altitudinal field defects strongly suggest NMOSD rather than MS, associated with more severe vision loss and poorer recovery 1
• Peripheral or altitudinal visual field defects are atypical for MS-related optic neuritis and mandate immediate investigation for NMOSD or systemic lupus erythematosus 1
• Arcuate defects can occur, particularly when associated with antiphospholipid antibodies suggesting an ischemic/thrombotic mechanism 1

Severity and Mechanism of Vision Loss in NMOSD

Greater Visual Dysfunction Compared to Other Demyelinating Diseases

• NMOSD regularly leads to more profound vision loss compared to both MS and MOG-antibody associated disease 3
• Visual acuity loss per micrometer of retinal nerve fiber layer thinning is stronger in NMOSD compared with MOGAD 3
• Visual dysfunction in NMOSD is associated with neuroaxonal damage beyond the effect seen in MS and MOGAD, potentially due to primary retinopathy or Müller cell pathology 3

Structural Correlates

• Foveal inner rim volume contributes to mean deviation and low-contrast visual acuity specifically in NMOSD eyes, not in MS or MOGAD 3
• Lower visual function correlates with peripapillary retinal nerve fiber layer and ganglion cell layer thinning, with a critical cutoff point at approximately 60 micrometers 3

Critical Diagnostic Algorithm When Peripheral Field Defects Are Present

Immediate Laboratory Testing

• Urgent serum antibody testing for AQP4-IgG and MOG-IgG is required when peripheral or altitudinal visual field defects are present 1
• These antibodies have significant therapeutic consequences requiring fundamentally different treatment approaches than MS 2

Imaging Protocol

• MRI of orbits and brain with contrast should be performed to identify posterior optic nerve/chiasmal involvement, long optic nerve lesions, or soft tissue enhancement extrinsic to the nerve 1
• Bilateral simultaneous involvement is common in NMOSD and represents a red flag for atypical optic neuritis 2, 1
• Long optic nerve lesions are suggestive of NMOSD, especially anti-MOG-IgG disease 2

Additional Workup for Autoimmune Etiologies

• Autoimmune workup including ANA, anti-dsDNA, and antiphospholipid antibodies should be performed if SLE is suspected 1
• Funduscopy to assess for optic disc edema, present in 30-40% of SLE-related cases 1

Clinical Pitfalls and Prognostic Factors

Time-Critical Treatment Considerations

• Treatment delay beyond 2 weeks worsens prognosis, particularly in SLE-related cases 1
• Acute-phase treatment should be initiated within 8 days of relapse 4
• MOG-antibody disease has a 50-60% relapse rate during corticosteroid taper, necessitating maintenance immunosuppressive therapy 2

Poor Prognostic Indicators

• Optic neuritis at disease onset predicts poor visual outcome in NMOSD patients 5
• Patients with ON at both disease onset and during relapse attacks have the poorest visual outcome 5
• Suspicion should be high in patients presenting with vision of light perception or worse, or those left with acuity of 20/50 or worse after optic neuritis 6
• Simultaneous bilateral optic neuritis or recurrent attacks increase suspicion for NMOSD 6

Visual Network Reorganization

• Severe visual impairment in NMOSD is associated with selective reorganization of the visual network, with increased primary visual network connectivity correlating with reduced visual acuity and more severe retinal damage 7
• Visual functional connectivity is significantly higher in patients with a history of optic neuritis compared to those without 7