Why Field Patterns Matter
The pattern of a visual field defect localizes the lesion along the visual pathway. Different diseases produce characteristic field loss patterns that can be recognized on the printed Humphrey visual field report. As a CPO, understanding these patterns helps you recognize significant findings and communicate effectively with the physician.
The Visual Pathway
Understanding field defect patterns requires knowing the visual pathway anatomy:
- Retina (each eye) → optic nerve → optic chiasm (nasal fibers cross) → optic tract → lateral geniculate body → optic radiations → occipital cortex
Lesions at different points along this pathway produce characteristic defect patterns because of how retinal fibers are organized at each level.
Common Glaucomatous Field Defect Patterns
Arcuate (Bjerrum) Scotoma
The most characteristic glaucomatous field defect. Retinal nerve fiber bundles arch around the fovea in an arcuate pattern. Glaucomatous damage to these fibers produces a curved arc-shaped defect that follows this arcuate course, typically in the superior or inferior field.
Nasal Step
A field defect that respects the horizontal meridian on the nasal side, producing a step-like discontinuity between the superior and inferior fields nasally. This occurs because the retinal nerve fibers above and below the horizontal raphe travel in separate bundles.
Paracentral Scotoma
Small defects near (but not involving) the central fixation point. These often precede larger arcuate defects and may be the earliest detectable glaucomatous field change.
Altitudinal Defect
A field defect affecting the entire upper or lower half of the visual field, respecting the horizontal midline. In glaucoma, dense inferior altitudinal defects reflect severe superior arcuate nerve fiber bundle damage.
Neurological Field Defect Patterns
| Pattern | Location | Lesion Site | Common Cause |
|---|---|---|---|
| Monocular loss | One eye only | Retina or optic nerve (pre-chiasmal) | CRVO, CRAO, optic neuritis, AION |
| Bitemporal hemianopia | Both temporal fields | Optic chiasm | Pituitary tumor |
| Homonymous hemianopia | Same side both eyes | Post-chiasmal (optic tract, radiation, cortex) | Stroke, tumor, trauma |
| Superior quadrantanopia | Upper quadrant, both eyes, same side | Temporal lobe optic radiation | Stroke in MCA territory |
| Inferior quadrantanopia | Lower quadrant, both eyes, same side | Parietal lobe optic radiation | Stroke in MCA territory |
| Congruous vs. incongruous | Varies | Cortical vs. tract lesions | More congruous = more posterior lesion |
Key Takeaways
- Arcuate scotoma and nasal step are the hallmark glaucomatous field defect patterns
- Monocular defects = lesion anterior to the chiasm (retina or optic nerve)
- Bitemporal hemianopia = chiasmal lesion (most commonly pituitary tumor)
- Homonymous hemianopia = post-chiasmal lesion (stroke, tumor)
- More posterior lesions produce more congruous (symmetric) homonymous defects