Loss of vision in the upper or lower half of the visual field, typically respecting the horizontal midline. Often indicates optic nerve or retinal disease.
An altitudinal visual field defect is loss of vision in either the upper or lower half of the visual field. The defect "respects" the horizontal midline, meaning it stops sharply at an imaginary horizontal line through the center of vision.
Key Takeaways
- Upper or lower half of visual field affected
- Respects horizontal midline—sharp border at middle
- Usually indicates optic nerve or retinal vascular disease
- Inferior altitudinal more common than superior
- Often sudden onset with vascular causes
What It Looks Like
Patients with altitudinal defects may describe:
- "Half my vision is missing"
- "Everything above/below is dark"
- Difficulty seeing steps or curbs (inferior defect)
- Difficulty reading signs overhead (superior defect)
Common Causes
Ischemic Optic Neuropathy
The most common cause of altitudinal defects is ischemic optic neuropathy:
- AION (Arteritic or Non-arteritic)
- Typically inferior altitudinal defect
- Sudden, painless vision loss
- Often noticed upon waking
- Optic disc swelling present
Branch Retinal Artery Occlusion (BRAO)
- Blockage of a branch of the retinal artery
- Sudden vision loss
- Defect corresponds to affected retinal area
- May see retinal whitening on exam
Branch Retinal Vein Occlusion (BRVO)
- Blockage of a branch of the retinal vein
- May develop gradually
- Associated with hemorrhages on exam
Other Causes
- Optic disc drusen
- Advanced glaucoma
- Optic neuritis (less commonly)
- Compressive lesions
Diagnosis
Visual Field Testing
- Visual field test (perimetry)
- Shows characteristic pattern
- Dense defect respecting horizontal midline
- May be complete or partial
Eye Examination
- Dilated fundus exam
- Look for optic disc abnormalities
- Check for retinal vascular disease
- May show disc edema
Additional Testing
Depending on suspected cause:
- Blood tests (ESR, CRP for giant cell arteritis)
- Fluorescein angiography
- OCT
- MRI if atypical features
Why Altitudinal?
The pattern occurs because:
- Optic nerve and retinal blood supply has superior/inferior watershed zones
- Vascular events often affect one half more than the other
- Nerve fiber bundles in the retina are arranged superiorly and inferiorly
Treatment
Treatment depends on the underlying cause:
Ischemic Optic Neuropathy
- Rule out giant cell arteritis urgently
- Control vascular risk factors
- No proven treatment for NAION
- See Ischemic Optic Neuropathy
Retinal Vascular Occlusion
- Evaluation for stroke risk factors
- Treatment of underlying conditions
- May need retinal procedures
Prognosis
- Depends on cause and severity
- Vascular causes often have limited recovery
- Some improvement possible over weeks to months
- Important to protect the other eye from same process
Living with Altitudinal Defects
Inferior Defects (Lower Vision Loss)
- Difficulty with stairs and curbs
- Use handrails
- Look down more consciously
- Good lighting important
Superior Defects (Upper Vision Loss)
- May miss overhead objects
- Be aware of low-hanging obstacles
- Adjust head position when walking
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment.
Medically Reviewed Content
This article meets our editorial standards
- Written by:
- Hashemi Eye Care Medical Team
- Medically reviewed by:
- Board-Certified Neuro-Ophthalmologist (MD, Neuro-Ophthalmology)
- Last reviewed:
- January 30, 2025