I flew to Boston, caught a bus to New Hampshire, then shared a car ride to my destination, all the while noticing how the fellow passengers kept their eyes – and conscious attention — pretty much focused on their phones. Certainly, not an uncommon sight, but one that made me again think about how standard eye testing is becoming out of step with modern society.

Eye evaluations continue to be based on a 150-year-old system that evaluates central eyesight by having a patient fix conscious attention on a non-moving target like an eye chart – or a phone. The system worked when much of the nation remained unsettled, overland travel was by horseback or horse-drawn wagons, and prairies and mountains dominated individuals’ peripheral sight.

But, general awareness of today’s fast-paced environment is highly dependent on peripheral eyesight. Modern society is awash in moving targets – from signs, lights and other vehicles whizzing past us in traffic to ever-changing GPS navigation screens and words rolling in and out of sight on scrolling web pages. We use peripheral and central eyesight in tandem to scan and shift our gaze from place to place, whether it be from a car dashboard to the road, from notes to a teacher or from a tennis ball to an opposing player. We typically use peripheral processing to guide where our attention is placed.

Only about six percent of surrounding awareness comes from conscious attention on specific objects. Most environmental signals passing through our retinas emanate from peripheral space – the space all around us. So, had I moved my head – or hand — close to one of my fellow riders engrossed in a phone, the action would have likely been caught by the corner of the rider’s eye, either startling the person or, at the very least, causing him or her to look up suddenly.

The brain usually turns on or tunes out peripheral/background auditory and visual signals and engages or disengages eye-aiming at targets depending on a person’s surrounding space and state of mind. When intact, such brain processing enables people to have some internal systems (such as balance and posture) running automatically. This “cruise control” allows a person to respond appropriately to the external world around them.

However, if brain circuitry is out of sync because it has been disrupted – or, in the case, of younger children, perhaps under-developed — people can become confused about their surrounding environment and exhibit inappropriate reactions and responses, Our filtering capability is hindered when body systems are impacted by extreme stress, injury or abnormal neurologic or metabolic conditions.

Patients with anxiety disorder, for example, are hypersensitive; their peripheral field is always “on” – both consciously and subconsciously. Children with attention deficit disorder are unable to tune out their background environment; everything that happens around them keeps shifting their attention. On the other hand, a person suffering from depression often has his or her peripheral processing primarily in the “off” position, shutting out the surrounding world.

Unfortunately, despite its critical role in our ability to perceive and function comfortably, peripheral eyesight – and its impact on brain function – remains largely untested. When it is tested, the patient has warning to “pay attention to the periphery.” Peripheral testing needs to be assessed at a subconscious level, including how it links with the 20/20 measurements of central eyesight. Thorough assessments should also include reaction times and accuracy of shifting gaze from place to place. With technology a constant part of people’s lives, we no longer stay put on stationary targets as much as we did 50 years ago.

We are almost 20 years into the 21st century. Time to leave 20/20 in the 20th century!

Deborah Zelinsky, O.D.
Executive Research Director
Mind-Eye Institute