Makindo Medical Notes

Related Subjects: |Anatomy the Medulla Oblongata |Anatomy of the Midbrain |Anatomy of the Pons

🧠 Introduction

🔹 About 30% of stroke patients develop post-stroke visual impairment. 🔹 Common symptoms: hemianopia, neglect, diplopia, ↓ visual acuity, ptosis, anisocoria, nystagmus. 🔹 Homonymous hemianopia affects ~8% of stroke patients – some may still be driving.

🧬 Aetiology

• 👁️ Homonymous hemianopia: Loss of the same right/left halves of the visual field in both eyes. ➡️ Cause: Stroke of optic radiation or occipital cortex (MCA or PCA infarcts). ➡️ Macular sparing may occur if dual MCA/PCA supply to occipital pole.
• ◼️ Quadrantanopia:
  • 🌙 Superior quadrantanopia: Temporal lobe lesion (“pie in the sky”).
  • 🌄 Inferior quadrantanopia: Parietal lobe lesion (“pie on the floor”).

📊 Range of Visual Field Losses

👁️ Left Homonymous Hemianopia (Patient’s View)

🔍 Visual Neglect

🧭 A parietal lobe syndrome → patients ignore one side (usually left). 🪒 May shave/eat only one side. 💡 Managed with occupational therapy & compensatory scanning strategies.

📖 Hemianopic Alexia

📚 Reading disorder post-stroke, usually left hemisphere → disrupts right visual field used for guiding eye movements. 🚨 Common, distressing, requires rehab input.

🚗 Driving & Visual Field Defects

Complete hemianopia = unsafe to drive. DVLA guidelines require assessment before resuming driving. DVLA guidance.

📏 DVLA Minimum Standards for Group 1 Drivers

• 120° horizontal field (≥50° left & right).
• No binocular defect within 20° of fixation.
• Homonymous/bitemporal defects close to fixation = not permitted.

DVLA testing includes: ✔️ Binocular Esterman field test (standard) ✔️ Monocular full-field charts (specific cases) ✔️ Goldmann perimetry (rare, strict criteria)

💊 Management of Visual Field Defects

• Multidisciplinary rehab: ophthalmology, orthoptics, OT, stroke physicians.
• Education + compensatory scanning strategies.
• Prism lenses → shift visual field.
• Refer to patient resources (Chest Heart & Stroke Scotland sheet).
• Prognosis variable → reassess at 2–3 months.

📚 References

• [1] Gilhotra JS, Mitchell P, Healey PR, et al. Homonymous visual field defects and stroke. Stroke 2002;33:2417-20.
• [2] Visual field defects after stroke. Aust Fam Physician, 2010.
• [3] DVLA Standards for Fitness to Drive.