The visual fields: an interdisciplinary history II. neurosurgeons and quantitative perimetry.

When operations for brain tumours became possible, exact charting of visual field defects assumed great importance in diagnosis and in monitoring post-operative progress. This process, known as quantitative perimetry, was energetically practised and taught by Harvey Cushing and by many of his pupils. The advent of non-invasive methods of imaging the brain and the rise of neuro-ophthalmology as an independent discipline were associated with a decline in neurosurgical commitment to quantitative perimetry, but it remains an important branch of the clinical neurosciences.