A Humphrey 24-2 visual field of a glaucoma patient shows a dense arcuate defect arching above the macula and terminating sharply at the horizontal midline nasally. This pattern reflects damage to which retinal nerve fibre bundles?

• A Temporal raphe fibres crossing the vertical midline
• B Papillomacular bundle fibres only
• C Nasal step fibres from the inferior retina
• D Superior arcuate fibres respecting the horizontal raphe ✓

Explanation

Retinal ganglion cell axons from the superior retina arc over the macula to enter the superior optic disc and respect the horizontal raphe, so their loss produces an upper arcuate (Bjerrum) scotoma that stops abruptly at the horizontal midline. This sharp horizontal demarcation distinguishes glaucomatous field loss from neurologic hemianopic defects, which respect the vertical meridian. Isolated papillomacular bundle involvement gives a central scotoma instead.

Reference: American Academy of Ophthalmology BCSC Glaucoma / Parson's Diseases of the Eye, Latest ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.