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).
I first read The man who mistook his wife for a hat some years ago, finding the title irresistible. The book concerns the case of a man with visual agnosia, a rare condition where a patient has normal visual input but is unable to make the correct visual perception association so consistently perceives objects as something other than their actual nature. This underlined dramatically the concept that, without appropriate visual processing by the brain, any amount of acuity is irrelevant.
This month sees an important paper published in Science journal showing the centre of the brain responsible for processing information needed for facial recognition continues to develop throughout life. This has important implications. Firstly, it reminds us of the geographical functionality of the brain and explains why facial recognition is lost in some brain lesions – something called prosopagnosia. Secondly, it shows how, from an evolutionary perspective, interpersonal interaction is a major driver to species success.
Don’t build walls!