Peripheral Vision Test

What it measures

This is a screening approximation of your peripheral (side) vision — the parts of what you see that lie away from where you're looking directly. Keeping your gaze fixed on a central cross, you respond to brief flashes that appear at different distances from the centre, in each of the four corners of the field, one eye at a time. It loosely mirrors the bedside 'confrontation' field test a clinician does by wiggling a finger at the edge of your vision. It does not measure your sharpness of vision (that is acuity) and it cannot map or quantify your visual field — it only gives a rough sense of whether flashes in the periphery are noticed for each eye.

How it works

You set the eye you're testing and sit roughly an arm's length away. A large cross sits in the centre as a fixation point. On each trial you press the field when your eye is steady on the cross, a dot then flashes very briefly (about a third of a second) at a random corner and distance from centre, and afterwards you click the corner where you saw it — or say you saw nothing. Because the dot vanishes before you respond, you must use your peripheral vision rather than turning your eye to look at it. The tool tallies how many of the twelve flashes you correctly located, including how you did at the far edge of the field, and repeats for the other eye when you re-take.

Tips for an accurate result

• 1Don't fight the urge to peek — It's natural to want to look at the dot. If you keep catching yourself, slow down — press for the flash only once your eye is genuinely settled on the cross.
• 2Blink before, not during — Blink to refresh your eye just before you press for each flash, so a blink doesn't make you miss a real target.
• 3Compare your two eyes — Run it for each eye and note any difference. One eye scoring noticeably worse — especially in the same corner each time — is more meaningful than the overall number.
• 4Watch for a consistent blind area — Random misses are normal. A spot or corner that's repeatedly dark, blurred or simply missing is the pattern worth taking to an optometrist.