Doing What Comes Naturally

Standard visual field (VF) tests are based on technology that is now almost half a century old. The goal is to quantify how sensitive each part of the eye is to light, and to detect any blind spots that may indicate eye disease. First, the patient’s head is positioned on a chinrest inside a device called a “Standard Automated Perimeter” – a basin-like structure sometimes referred to with feeling as “the large toilet bowl.” Then, they are instructed to strictly fixate on a central cross, while remembering to press a button whenever they see a dot of light appear anywhere in the bowl.  This procedure typically takes around 10 minutes (5 minutes per eye) – and throughout this time they must try to remain perfectly motionless from the neck up, because any head or eye movements can result in the lights appearing at the wrong location on the back of the eye: rendering the results meaningless.