Visual Field Defects & Pathway Lesions

The single most "localisable" topic in neuro-ophthalmology: a defect on perimetry tells you exactly where the lesion sits along the visual pathway. Master the rule of the chiasm (decussation of nasal fibres) and congruity, and almost every PYQ falls into place. These notes walk the pathway anteriorly → posteriorly and map each lesion to its field defect. Light from a point in space hits the opposite half of each r…