How to investigate and treat non-arteritic ischemic optic neuropathy (NAION)?

Investigation and Treatment of Non-Arteritic Ischemic Optic Neuropathy (NAION)

For patients with suspected NAION, a thorough diagnostic evaluation followed by risk factor modification is the mainstay of management, as there is currently no proven effective treatment for this condition. 1, 2

Diagnostic Evaluation

Clinical History

• Duration of vision loss 3
• Presence of cardiovascular risk factors (hypertension, diabetes, hyperlipidemia) 2
• Medication history 3
• Family history of cardiovascular disease 3
• Ocular history (trauma, previous surgeries) 3
• Social history (smoking) 3
• Rule out symptoms of giant cell arteritis (headaches, scalp tenderness, jaw claudication, temporal tenderness) 3

Clinical Examination

• Visual acuity assessment 3
• Pupillary assessment (relative afferent pupillary defect) 3
• Slit-lamp biomicroscopy 3
• Intraocular pressure measurement 3
• Dilated fundus examination to assess:
  • Optic disc edema 2
  • Retinal hemorrhages 3
  • Cotton wool spots 3
  • Retinal emboli 3
  • Vascular abnormalities 3

Ancillary Testing

• Color fundus photography to document optic disc edema and retinal findings 3
• Optical Coherence Tomography (OCT) to assess:
  • Retinal nerve fiber layer thickness 3
  • Macular thickness 3
  • Vitreoretinal interface 3
• Optical Coherence Tomography Angiography (OCTA) to evaluate vascular perfusion (emerging technology) 4
• Fluorescein angiography to:
  • Evaluate extent of vascular occlusion 3
  • Assess degree of ischemia 3
  • Rule out concomitant retinal vascular disease 5
• Visual field testing to document pattern and extent of visual field defect 3
• Laboratory tests to rule out arteritic causes (ESR, CRP) 1

Treatment Approach

Acute Management

• No proven effective treatment exists for NAION 1, 2, 6
• Systemic corticosteroids have been used but remain controversial and unproven in controlled trials 6
• Optic nerve sheath decompression is not recommended 6
• Antiplatelet therapy (aspirin) may be considered to reduce risk to the fellow eye, though evidence is limited 4

Risk Factor Modification

• Control of hypertension 2
• Management of diabetes mellitus 2
• Treatment of hyperlipidemia 2
• Smoking cessation 3
• Avoidance of medications that may exacerbate hypotension, particularly at night 2
• Correction of sleep apnea if present 2

Monitoring and Follow-up

• Regular monitoring of the unaffected eye is essential as there is risk of involvement of the fellow eye 1
• Serial visual field testing to monitor for progression or improvement 3
• OCT monitoring of retinal nerve fiber layer thickness 3

Special Considerations

• In cases with concomitant branch retinal vein occlusion, additional treatment approaches may be needed 5
• Neuroprotective strategies are under investigation but not yet proven in clinical practice 6
• Avoid vasoconstrictive medications 2

Prognosis

• Visual recovery is variable and often limited 1
• Approximately 40% of patients may experience some spontaneous visual improvement 2
• Risk of involvement of the fellow eye is approximately 15-20% within 5 years 2
• The primary goal of management is prevention of further episodes in either eye 2, 6