Score Item 2 (Best Gaze) from what you observe, not from what the patient reports seeing: if the person cannot visually track your finger because of long-standing bilateral glaucoma, score the item based on the eye movement actually elicited, and if no tracking movement can be obtained, score it as 3 (not testable) rather than assigning a normal score. Glaucoma blindness removes the visual target, not necessarily the eye movement. The examiner must separate an inability to see the target from an inability to move the eyes.
The NIH Stroke Scale (NIHSS) Item 2 grades horizontal eye movement only. It asks the examiner to assess voluntary or reflexive gaze using a finger or face, and it explicitly allows reflex testing in a patient who cannot follow commands. This is the crux of the glaucoma case: the patient cannot see the finger, so the finger is a poor stimulus, but the oculomotor apparatus may still be intact.
What Item 2 Actually Measures
Item 2 is a brainstem and cortical eye-movement item, not a vision item. It scores gaze deviation, partial gaze palsy, and forced deviation. The examiner looks for whether the eyes can move horizontally to the left and right, whether there is a resting deviation, and whether a reflex can overcome any deviation.
A person blind from glaucoma has no functioning retinal input from the optic nerve. The eyes may still be driven by the brainstem and by reflex pathways. That distinction is why a blind patient can have a normal Item 2 if eye movements are full, and an abnormal Item 2 if there is a gaze palsy from a separate lesion.
The item does not test visual acuity, visual fields, or fixation. It tests the motor output of gaze. A patient who cannot see your finger can still have intact conjugate eye movements, and a patient who sees perfectly can have a gaze palsy.
Why Blindness Does Not Automatically Mean a Gaze Palsy
Horizontal gaze is generated by the paramedian pontine reticular formation and the abducens nucleus on one side, coordinated with the contralateral medial longitudinal fasciculus and oculomotor nucleus. This circuitry does not require the retina to fire. It requires intact brainstem and nerve pathways.
Visual tracking is a cortical and cerebellar function that depends on a visible target. When the target is invisible, smooth pursuit cannot be generated visually. But the eyes can still move to command, to a sound, or to a reflex. A blind patient may move the eyes toward a voice or toward a tactile stimulus.
Long-standing glaucoma causes progressive retinal ganglion cell loss and optic nerve damage. It does not directly lesion the oculomotor nuclei or the brainstem gaze centers. So the default expectation in isolated glaucoma blindness is preserved eye movement, not gaze palsy.
The professional caveat: a blind patient may have an apparent gaze deviation at rest that is a blind-eye phenomenon, not a stroke. Some blind individuals develop a slow, wandering, or divergent resting eye posture. That resting posture can be mistaken for a forced deviation if the examiner does not test reflexively.
Scoring the Item Under NIHSS Rules
The NIHSS Item 2 scoring convention is:
0 = Normal: eyes move fully to both sides. 1 = Partial gaze palsy: gaze is abnormal in one or both eyes, but no forced deviation is present. 2 = Forced deviation or total gaze paresis: the deviation cannot be overcome by voluntary effort or reflex. 3 = Not testable: the patient cannot cooperate, or the eyes cannot be assessed.
The 3 score is reserved for genuine inability to assess, such as a patient who cannot cooperate, has a pre-existing gaze disorder that obscures the examination, or has an ocular condition that prevents observation. Blindness alone does not automatically force a 3 if eye movements can still be observed.
If the patient cannot see the finger but the eyes still move horizontally to a voice or a reflex, the examiner should score the movement observed, not the tracking failure. If no eye movement can be elicited at all despite effort, the item is not testable and is scored 3.
A counterintuitive point: the NIHSS allows reflex testing precisely because command-following can fail for reasons unrelated to gaze. A blind patient who does not follow the finger is not necessarily uncooperative; the stimulus is simply invisible. The examiner should switch to an auditory or tactile target before concluding the item is untestable.
Comparison of Scoring Approaches
| Clinical situation | Finger tracking result | Reflex or alternate target | Recommended Item 2 score |
|---|---|---|---|
| Blind from glaucoma, full eye movements to voice | Cannot track finger | Eyes move fully to voice | 0 |
| Blind from glaucoma, partial limitation one side | Cannot track finger | Partial movement to voice | 1 |
| Blind from glaucoma, eyes fixed and deviated | Cannot track finger | No movement to voice or reflex | 2 if forced deviation confirmed; 3 if cannot assess |
| Sighted patient, cannot follow commands | No tracking | Reflex gaze present | Score based on reflex |
| Sighted patient, forced deviation | No tracking past midline | Cannot overcome deviation | 2 |
| Patient with pre-existing strabismus | Variable | Variable | Score what is observable; note limitation |
The table shows that the score depends on the observed movement, not on the visual status. The same blind patient can score 0, 1, 2, or 3 depending on what the eyes actually do.
Edge Cases That Change the Score
Several situations complicate the glaucoma case. Each requires the examiner to document what was done and why the score was assigned.
A patient with long-standing blindness may have nystagmus, wandering eyes, or a resting esotropia. These are ocular motor findings, not necessarily gaze palsies. The examiner should distinguish a stable resting deviation from a forced deviation that cannot be overcome.
A patient with glaucoma may have had prior eye surgery, including trabeculectomy or tube shunt placement. These do not usually affect gaze, but periorbital swelling or pain can limit eye opening and confound observation.
A patient with bilateral blindness from glaucoma may also have diabetic neuropathy, thyroid eye disease, or a prior stroke. These comorbidities can produce a genuine gaze palsy. The examiner should not attribute all gaze abnormality to blindness.
A patient who is blind and has a decreased level of consciousness may not move the eyes at all. In that case, the item is not testable and is scored 3, but the reason is depressed consciousness, not blindness.
Common Misconceptions
The most common misconception is that a blind patient automatically scores 3 on Item 2. That is false. The item can be scored if eye movements are observable. Blindness affects the stimulus, not necessarily the response.
A second misconception is that failure to track the finger means a gaze palsy. Smooth pursuit requires a visible target. A blind patient cannot pursue a target they cannot see. That failure is expected and does not indicate a neurologic deficit.
A third misconception is that a resting eye deviation in a blind patient is a forced deviation. Chronic blindness can produce a stable, non-forced deviation. The examiner must test whether the deviation can be overcome.
A fourth misconception is that the NIHSS cannot be used in blind patients. The scale explicitly permits reflex testing and alternative stimuli. The examiner should adapt the stimulus, not abandon the item.
Practical Actions for the Examiner
The following steps make the scoring reproducible and defensible.
First, confirm the patient cannot see the finger by asking and by observing. Do not assume blindness from the chart alone. Second, switch to an auditory target: call the patient's name from the left and right and observe eye movement toward the sound. Third, use a tactile or reflexive stimulus: a light touch to the canthus or a passive head turn can elicit reflexive eye movement. Fourth, document the stimulus used and the movement observed, including any resting deviation. Fifth, if no movement is obtainable, score 3 and state the reason: inability to cooperate, depressed consciousness, or obscuring ocular condition. Red flag: a new forced deviation in a blind patient with sudden onset suggests a stroke and warrants urgent evaluation, not attribution to glaucoma.
The practical threshold is simple: if you can see the eyes move to an alternative target, score the movement. If you cannot see or elicit any movement, score 3 and explain.
Limitations and Documentation
The NIHSS Item 2 was validated primarily in sighted patients with acute stroke. Its performance in blind patients is not well studied. The examiner should document the adaptation used and recognize that the score reflects observed eye movement, not visual function.
A blind patient with a normal Item 2 can still have a serious posterior circulation stroke that does not affect horizontal gaze. The NIHSS is a screening tool, not a complete neurologic examination. A normal Item 2 does not exclude stroke.
Documentation should include the stimulus, the observed movement, the presence or absence of resting deviation, and the reason for any 3 score. This protects against later challenges to the score and supports clinical decision-making.
The glaucoma blindness itself is not a reason to skip Item 2. The item remains informative when the examiner adapts the stimulus and scores what is seen.
This article is general educational information about scoring a clinical scale. It is not a diagnosis, treatment plan, or substitute for clinical judgment. A qualified clinician should evaluate any patient with suspected stroke or new gaze abnormality, and immediate danger warrants local emergency services.