Lesions posterior to the optic chiasm produce homonymous visual field loss—overlapping scotomas in the nasal field of one eye and the temporal field of the other eye. Patients retain normal acuity, but find their lives changed forever. A homonymous hemianopia, when complete, makes safe driving impossible and reading a chore. Although some patients experience partial, spontaneous improvement following the acute phase of an event, most remain handicapped by permanent field loss. No treatment was available before the recent advent of visual restoration therapy.

In a sensational series of reports, Sabel and colleagues (Kasten et al) have described partial recovery of homonymous visual field defects by intensive computer based rehabilitation therapy.^1–3 Their approach is remarkably simple. Patients practise perimetry at home for an hour a day, 6 days a week, for 6 months, using a software program loaded on their personal computer. A chin support is used for head stability and a monitor is placed 30 cm away. Stimuli are white, suprathreshold lights measuring 0.15° in diameter shown against a dark background. Protocols are tailored for each patient to present most stimuli near the border of the field defect (“transition” zone) to maximise potential therapeutic benefit. Sabel has founded a company (NovaVision) that offers visual rehabilitation therapy for about €5000.

The idea behind visual restoration therapy is that after stroke or traumatic brain injury, a region …