Question:medium
A 33 year old female patient presented with inability to see the right side from both the eyes. What is the most probable cause?
A 33 year old female patient presented with inability to see the right side from both the eyes. What is the most probable cause?
Show Hint
Think about which side of the brain processes the right visual field.
Updated On: Jun 23, 2026
- Injury to Left Optic Tract
- Right occipital lobe lesion
- Optic chiasma lesion
- Right optic nerve lesion
Show Solution
The Correct Option is A
Solution and Explanation
The patient has loss of the right visual field in both eyes, which is called right homonymous hemianopia.
Key rule: The left optic tract carries fibres from the nasal retina of the right eye (which crossed at the chiasma) and the temporal retina of the left eye. These fibres together encode the right visual field.
A lesion of the left optic tract therefore eliminates the right visual field from both eyes simultaneously -- producing right homonymous hemianopia.
Differential reasoning:
- Optic chiasma lesion → bitemporal hemianopia (lose outer fields of both eyes)
- Right optic nerve lesion → total monocular blindness in the right eye
- Right occipital lobe lesion → left homonymous hemianopia (opposite side) \[\boxed{\text{Left optic tract injury}}\]
Key rule: The left optic tract carries fibres from the nasal retina of the right eye (which crossed at the chiasma) and the temporal retina of the left eye. These fibres together encode the right visual field.
A lesion of the left optic tract therefore eliminates the right visual field from both eyes simultaneously -- producing right homonymous hemianopia.
Differential reasoning:
- Optic chiasma lesion → bitemporal hemianopia (lose outer fields of both eyes)
- Right optic nerve lesion → total monocular blindness in the right eye
- Right occipital lobe lesion → left homonymous hemianopia (opposite side) \[\boxed{\text{Left optic tract injury}}\]
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