A 30-year-old patient with known multiple sclerosis presents with painful loss of vision in one eye, reduced colour vision, and an RAPD. OCT shows retinal nerve fibre layer (RNFL) thinning in the superior and inferior arcuate bundles. MRI reveals a T2 hyperintense lesion in the right optic nerve. Which visual field defect is most characteristic during the acute phase of optic neuritis?
- A Bitemporal hemianopia
- B Altitudinal field defect
- C Central or centrocecal scotoma ✓
- D Homonymous hemianopia
Explanation
Optic neuritis characteristically produces a central or centrocecal scotoma (involving the fixation point ± blind spot), reflecting damage to the papillomacular bundle — the concentration of fibres subserving central vision that runs axially through the optic nerve. Colour vision loss (classically red desaturation) precedes and persists beyond visual acuity recovery. Bitemporal hemianopia is a chiasmal lesion. Altitudinal field defects are classic for anterior ischaemic optic neuropathy (AION) — a 'stroke' of the optic nerve — not optic neuritis. Homonymous hemianopia results from retrochiasmal lesions.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.