NIH Stroke Scale Visual Field Scoring: Definitions
On the NIH Stroke Scale Item 3 (Visual Fields), partial hemianopia (score 1) indicates incomplete loss of vision in one half of the visual field, complete hemianopia (score 2) indicates total loss of vision in one half of the visual field, and bilateral hemianopia (score 3) indicates visual field loss affecting both sides, including cortical blindness. 1, 2
Detailed Scoring Breakdown
Score 0: No Visual Field Defect
- Normal visual fields bilaterally on confrontation testing
- Patient can see fingers/stimuli in all four quadrants
Score 1: Partial Hemianopia
- Incomplete loss of vision in one hemifield (left or right)
- Includes:
- Quadrantanopia (loss of one quadrant)
- Partial field cut that doesn't encompass the entire hemifield
- Visual extinction to double simultaneous stimulation
- Patient can still detect some stimuli in the affected hemifield, but not all 3, 2
Score 2: Complete Hemianopia
- Total loss of vision in one entire hemifield (left or right)
- Patient cannot detect any visual stimuli throughout the entire affected half of the visual field
- This is a dense, homonymous hemianopia affecting all quadrants on one side 1, 2
Score 3: Bilateral Hemianopia
- Visual field loss affecting both sides
- Includes:
- Bilateral homonymous hemianopia
- Cortical blindness (complete loss of vision from bilateral occipital damage)
- This represents the most severe visual field deficit on the scale 3, 2
Clinical Testing Method
Visual fields are assessed using confrontation testing (or visual threat if necessary) 3. The examiner presents fingers or visual stimuli in each quadrant while the patient fixates on the examiner's nose, testing each eye's visual field systematically.
Prognostic Implications
Complete hemianopia carries worse prognosis than partial hemianopia. Research shows 28-day mortality of 49% with complete hemianopia versus only 11% with partial hemianopia, reflecting greater extent of cerebral damage 4. Recovery occurs in approximately 17% of patients with complete hemianopia versus 72% with partial hemianopia 4. Visual impairments at baseline, particularly complete hemianopia, are independently associated with poor modified Rankin Scale outcomes at 90 days 5.
Common Pitfall
Do not confuse visual field defects with gaze palsies (Item 2 on NIHSS). Gaze abnormalities reflect eye movement disorders, while hemianopia reflects actual visual field loss in the retinogeniculate-occipital pathways. A patient may have normal eye movements but still have hemianopia from posterior circulation stroke 6.