Bill Harvey: Vision is not just Snellen

I am always concerned that we tend to focus too much on Snellen acuity as the gauge for vision quality when much of what we see, indeed perhaps most, is down to higher processing by the brain. Indeed, the very success of the human race has been driven by our ability to communicate and interact as a social community and this has been aided by the way our visual system has evolved.

Readers may be aware of the late neurologist Oliver Sachs – hopefully through his excellent books (one of his later works, Hallucinations, is well worth a look and offers a wonderful insight into Charles Bonnett to the wider public) and not from film tie-ins (I was unimpressed by the schmaltzy Awakenings).