A 45-year-old man has a dense central scotoma in the right eye and a superotemporal field defect confined to the left eye. MRI demonstrates a small mass at the right optic nerve just where it joins the chiasm. This combination is called:

• A Junctional scotoma of Traquair
• B Junctional scotoma ✓
• C Bitemporal central scotoma
• D Wernicke hemianopic scotoma

Explanation

B lesion at the anterior chiasmal junction damages the ipsilateral optic nerve fibres plus Wilbrand's knee, the loop of crossing inferior nasal fibres from the opposite eye that sweeps forward into the contralateral nerve before turning back. This yields an ipsilateral central scotoma with a contralateral superotemporal defect. Traquair's junctional scotoma is different: it is a monocular temporal hemianopia from a lesion at the junction, without any field loss in the fellow eye.

Reference: Khurana's Comprehensive Ophthalmology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.