Peripheral vision assessments

Peripheral Vision Assessments

In optometry, most of the time we examine your central vision – the part you use when you look directly at things. Your peripheral vision is what gives you the “bigger picture” and is important in allowing you to get around without bumping into things. When people have peripheral vision problems, they’re often not aware of them for a long time. As an everyday example, we all have a natural “blind spot.” This correlates with the head of the optic nerve inside our eyes. It’s quite close to our central vision, but still technically “peripheral,” and most people are surprised they even have a blind spot. Try this simple experiment. Cover your left eye and look at something (smallish) directly in front of you. Hold your right index finger up directly between you and the object you’re observing, then slowly move your finger to your right. Before you hit a ruler’s length to your right, the tip of your finger simply disappears. Does this affect you in everyday life? No, and you’d usually never even know it was there, even though it’s only just in the periphery.

Because self-assessment with peripheral vision is not reliable, computerized perimetry – measuring your peripheral vision – is a useful tool for 2 reasons:
It screens for neurological “surprises”, and
It gives us a benchmark for comparison, in case your peripheral vision changes over time.

The most common peripheral vision problems are caused by glaucoma, which is a common and blinding eye disease. Glaucoma vision problems start in the periphery, gradually causing tunnel vision and eventually blindness, when undetected and untreated. As nobody is immune from glaucoma, and because pressure tests can sometimes give misleading results, at ICU we like to have the full picture of your vision and eye health right from your first visit. The first peripheral vision test we perform is a simple screening test. It involves clicking a button whenever you see a light flash in our computerized perimeter. This is quick and easy. The next time perimetry is performed is typically at your next 2-yearly checkup. This time it’s a little harder, involving flickering lights. Because this test is more sensitive, its result now becomes our “real” benchmark. We don’t do this test at the first visit, because typically people get it wrong and we have to do it again anyway! Once we have a good result with the “flicker” test, it is repeated every 4 years thereafter. This gives a good balance between doing it too frequently and not letting you get out of practice with it. If any changes occur to your peripheral vision, they allow us to make assessments to determine whether you need ophthalmological care, whereupon a timely referral to an eye doctor will be organized for you.