Examine this patient's eyes.
Examine this patient's visual fields.
· The patient bumps into things on one side and may have a history of traffic accidents where one side of the car is damaged without
the patient realizing.
· The patient may insist that he/she has one 'bad' eye (remember, blindness in one eye causes impairment in perceiving
distances but the normal eye will provide a full field of vision on both sides and hence the patient will not bump into objects).
· Reading difficulty (suggests that the visual defect splits the midline: if the defect is on the right side, the patient is unable to
scan along the line to the next word and hence reading is almost impossible, whereas when the defect is on the left side the
patient cannot find the beginning of the next line).
· Determine whether the patient is aware of his/her defect (if the patient is aware of the visual defect it is likely that the defect
'splits' the macula and bisects the central field, whereas if the patient is unaware and bumps into things, then the defect is
either macular sparing or an attention hemianopia).
Testing for homonymous hemianopia includes:
· Testing for an attention field defect using both hands of the examiner and asking the patient to determine which finger is
· Testing of the whole field in each eye using a white hat pin.
· Re-evaluation of the field in each eye to determine whether there is macular sparing or macular splitting using a hat pin.
If you are unable to determine, then tell the patient that you would like to do formal field testing with a tangent screen or using a
Proceed as follows:
· Check the visual acuity; examine the fundus.
· Tell the examiner that you would like to do a full neurological examination to look for an underlying cause: -Stroke.
- Intracranial tumour.
This patient has a homonymous hemianopia (lesion) for which I would like to determine the aetiology, such as a stroke or tumour.
Where is the lesion?
The lesion is in the optic tract and beyond (visual acuity is intact when the macula is spared):
What further investigations would you do?
· Formal field testing: perimetry is particularly important if the patient holds a driver's licence.
· CT head scan.