Junctional Scotoma, Junctional Scotoma of Traquair
Despite the similarity of these terms, they are used to refer to different types of scotoma:
- Junctional scotoma:
Unilateral central scotoma with contralateral superior temporal defect, seen with lesions at the anterior angle of the chiasm; this is said to damage the ipsilateral optic nerve plus the crossing loop of fibers (Wilbrand’s knee) originating from the inferonasal portion of the contralateral eye (it may be noted that some authors have questioned whether such a loop in fact exists).
- Junctional scotoma of Traquair:
A monocular temporal scotoma, sometimes even hemianopia, seen with optic nerve involvement sufficiently close to the chiasm to involve only ipsilateral crossing nasal axons, which subserve the temporal visual field, but sparing nasal axons crossing from the contralateral eye.
Larner AJ. A developing visual field defect. Postgraduate MedicalJournal 2002; 78: 106, 112-113