Stroke Affecting the Entire Occipital Lobe on One Side – 'Homonomous Hemianopia'When the stroke affects most of the occipital lobe on one side of the brain, the visual problem that arises is called homonymous hemianopia, in which a person is not able to see objects on the opposite side of the stroke. So if someone were to suffer a stroke in the left side of the brain, they would have difficulty seeing objects on the right side.
Stroke Affecting the Occipital Pole – 'Central Vision Defect'The occipital pole is the area of the brain where central vision is processed. By central vision, we mean what you see at the center of the visual field when you are looking straight ahead. Therefore, a stroke there would cause you to have a large blind spot in the very middle of your visual field on the affected side.
A person with such a deficit may have trouble looking straight ahead at someone’s face, as she may not be able to see the person's nose, upper lip, and the lower half of the eye on the affected side, but they could see the shoulder and the top of their head on that side. Thankfully, these strokes are rare, but when they do occur the visual problem that arises is called “central visual defect.”
Stroke Affecting the Occipital Lobes on Both Sides – 'Cortical Blindness'When the occipital lobes of the brain are completely affected by a stroke, the end result is a phenomenon called “cortical blindness.” In essence this is the same as what we all understand by the term “blindness,” but doctors use this term in order to convey to each other that the specific reason for blindness in that person is damage to the brain cortex. People with cortical blindness sometimes also suffer from a condition called visual anosagnosia. Another name for this is Anton syndrome.
Other Symptoms of Occipital Stroke
- Visual Illusions
- Visual Hallucinations
- Visual Agnosias
- Balint Syndrome
- Alexia without Agraphia
Allan Ropper and Robert Brown, Adam's and Victor's Principles of Neurology, 8th Edition McGraw-Hill Companies Inc, United States of America, 2005, pp 417-430.