Automated perimetry of a 66-year-old man with cup-disc ratio 0.7 shows a dense superior arcuate scotoma extending to the horizontal meridian but sharply respecting it, with an associated nasal step. The corresponding retinal nerve fibre layer damage is located:
- A Inferior pole of the retina ✓
- B Superior pole of the retina
- C Nasal retina between the disc and macula
- D Temporal retina peripheral to the macula
Correct answer: A. Inferior pole of the retina
Explanation
Glaucomatous field defects respect the horizontal raphe because retinal nerve fibres arch above and below it without crossing. The visual field is inverted and reversed relative to the retina, so a superior arcuate scotoma indicates loss of inferior pole nerve fibres, which corresponds clinically to inferior neuroretinal rim thinning. Neurological field defects such as hemianopias respect the vertical meridian instead.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.