Differential Comparison

Select two movements to compare side-by-side with live animation and differential analysis.

Clinical vignette + eye movement — name the diagnosis. Select an answer then reveal explanation.

🔬 INO Severity Grading

Select INO from the movement list, then choose a grade below. Grade 1 = subtle lag; Grade 4 = complete adduction failure.

Signal Trace

Real-time position trace — Blue: O.D. horizontal  |  Orange: O.S. horizontal  |  Red: vertical  |  Purple: torsion OD

6 extraocular muscles — right eye, frontal view. MR/LR = rectus pair; SR/IR = vertical rectus; SO/IO = obliques.

🔍 HINTS Protocol

Select HINTS Exam from the movement list. Step through Head Impulse → Nystagmus → Test of Skew → Hearing (S+) to distinguish central (stroke) from peripheral (benign) vertigo. All 4 positive = STROKE.

🔁 BPPV Fatigability

Select BPPV Posterior from the list. Each repeated Dix-Hallpike reduces amplitude by ×0.7 (canalolithiasis fatigues). Cupulolithiasis does NOT fatigue.

completed Dix-Hallpike cycles

↪ Returning to upright — press again to trigger next cycle

📏 Alexander's Law

Select Alexander's Law Demo. Watch nystagmus intensity rise in right gaze (toward fast phase) and fall in left gaze (away from fast phase).

Fast phase = right. Right gaze = 150% · Center = 80% · Left gaze = 40%

🌀 Inner Ear Canal Anatomy

Shows which semicircular canal is affected. Select any BPPV variant from the list — the active canal highlights and debris animates.

🧠 Brainstem Pathway Map

Interactive brainstem localisation. Hover a structure to see its function. Click to load the eye movement it produces when damaged.

Observe the eye movement in the simulator above. Identify which cerebellar structure is lesioned.

🌡️ COWS Caloric Step-Through

Cold Opposite · Warm Same — step through all 4 caloric combinations with physiology.

⚡ Wernicke's Encephalopathy Progression

Auto-cycles through 3 stages (~12 sec each). Select Wernicke's Encephalopathy from the list.

Observe the eye movement in the simulator. Decide: is this pattern Central (brainstem/cerebellar) or Peripheral (labyrinth/vestibular nerve)?

🌀 Head-Shaking Nystagmus Test

Select Head-Shaking Nystagmus Test. Phase 1 (10s): horizontal head oscillation. Phase 2: post-shake nystagmus with exponential decay. Choose variant below.

📳 Vibration-Induced Nystagmus (VIN)

Select VIN + affected ear (sidebar). 100Hz mastoid vibration — nystagmus ONLY during stimulus. SPV ≥2°/s = abnormal.

💨 Hyperventilation-Induced Nystagmus (HVIN)

Select HVIN + affected ear (sidebar). Auto-cycles: 30s hyperventilation → nystagmus builds → 15s rest.

🔊 Superior Canal Dehiscence (SCDS)

Select SCDS from dropdown. No nystagmus at rest. Activate sound or pressure stimulus below.

😴 Myasthenia Gravis — Fatigability

Select Myasthenia Gravis — Ocular Fatigability. Eyes in sustained upgaze — watch progressive drift down over 60 seconds as NMJ fatigues.

🎯 Optokinetic Nystagmus (OKN)

Select Optokinetic Reflex (OKN). OKN is a visual reflex — full amplitude is present when the patient sees the rotating drum. Set drum rotation direction below.