Optic Nerve Clinical Notes and Interpretation
- The patient must have intact cognitive abilities and the ability to cooperate in order to successfully accomplish the previously described examination tasks.
- Visual acuity testing is typically performed with corrective lenses, if the patient commonly uses them, but can be performed without them.
- Differences of more than one line in visual acuity should be referred to an ophthalmologist.
- Macular degeneration, cataracts, and retinal disease may cause blind spots.
- An optic nerve lesion will produce complete or partial blindness in the involved eye.
- A complete lesion in one optic tract or in one lateral geniculate body results in blindness in opposite visual fields (i.e., nasal and temporal) of both eyes.
- A temporal lobe lesion may produce blindness in the upper quadrants of both visual fields contralateral to the lesion.
- A parietal lobe lesion may produce contralateral blindness in the lower quadrants of both eyes.
- Occipital lesions cause contralateral changes with macular sparing.
- Cortical blindness can also occur from occipital lesions, particularly to association areas.
- Pre-chiasmatic lesions result in ipsilateral loss of vision (i.e., retinal tumors, masses affecting the optic nerve).
- Chiasmic lesions result in bi-temporal hemianopsia (i.e., pituitary tumors, Berry aneurysm).
Point here to view typical visual field deficits