Occipital Lobe Lesion

Occipital Lobe Lesion
SYMPTOMS Palinopsia, Visual hallucinations, Vision loss Right sided homonymous hemianopia: Difficulty seeing next letter or word
Left sided homonymous hemianopia: Difficulty finding the next line
SIGNS Fundus and optic nerves appear normal
WORK-UP Pupils (typically normal) | EOMs (typically FROM) | Cover test | Color vision (Dyschromatopsia may be present) | Complete eye exam with dilation | Cranial nerve testing | Ptosis testing
OCT of the optic nerve | OCT of the macula (Ganglion cell loss that correlates with visual field loss) | VEP
Visual field threshold 30-2:
Homonymous hemianopia: Very congruent. Lesion is on side opposite the homonymous hemianopia
Paracentral homonymous scotomas: Very congruent. Lesion is at the tip of the occipital lobe on side opposite the homonymous hemianopia
Macular sparing: A homonymous hemianopia that spares fixation by about 2-3 degrees. Lesion involves anywhere along the visual radiations on
Bilateral central scotomas: Lesion involves both sides of the occipital lobe
Ring scotoma: A small area of central vision remains. Lesion involves both sides of the occipital lobe
Bilateral altitudinal defect: Altitudinal defects are usually inferior. Lesion involves both side of the occipital lobe
Checkerboard field defects: Crossed quadrantanopia. Lesion is above the calcarine fissure on one side and below the calcarine fissure on the other side
Octopus or Goldmann kinetic visual field:
Temporal crescent sparing: Typically associated with incongruent homonymous hemianopia and sparing of the temporal field 60-90 degrees in one eye. Lesion involves the occipital lobe but spares the anterior portion of the occipital lobe. This field defect could be missed with a static visual field 30-2
TREATMENT Refer to neuro-ophthalmologist/neurology for further evaluation and treatment
After treatment, most visual recovery is noted in 1-4 months. Visual recovery after 6 months is unlikely. If visual symptoms are still present, patient should undergo vision rehabilitation and vision restorative training (glasses, prism, tint, etc)
FOLLOW-UP Patient will likely be monitored by neurology/neuro-ophthalmology on a regular basis. Patient should be evaluated once underlying neurological etiology is in control or stable.
Monitor every 3 months for the first year and then every 6-12 months
ADDITIONAL LAB | TESTS MRI with and without contrast of the brain (concentration on the occipital lobe) | Neurological evaluation
ETIOLOGY Occipital lesions are typically due to tumors, strokes, and trauma
DIFFERENTIAL DX Temporal lobe lesion, Optic chiasm lesion, Parietal lobe lesion
NOTES Cortical blindness: Loss of vision in both eyes due to lesions that involve both striate cortexes of the occipital lobes. The pupils and fundus are normal in both eyes. These patients may inform others that they see things even if they actually don’t (Anton’s syndrome). The most common cause is a stroke that involves posterior circulation, but can be seen with manipulation of the neck from chiropractors or carbon monoxide poisoning