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Home » What's New » Retinoscopy: How Does it Work?

During some eye exams, your eye doctor might shine a beam of light into your eye, and hold various lenses in front of it. But what does this do? This test is a retinoscopy examination, and if you struggle with accurate vision, this is one way the eye doctor could find out. By examining the reflection of light off your retina, the optometrist can assess whether you are nearsighted, farsighted or have astigmatism, and can also measure the prescription you would need to correct your vision.

The most important thing your doctor is looking for during this exam is how accurately your eyes can focus on the light. When we use the retinoscope to shine light into your eye, a reddish light reflects off your retina, through your pupil. This is known as the red reflex. This process measures your focal length, or in layman's terms, it will determine the angle of refraction of light off your retina. And this is what lets us know how well your eye is able to focus. And if we see that you are not focusing well, that's where the lenses come in. We hold a number of prescription lenses in front of the eye to determine which one fixes the refractive error.

Your retinoscopy exam is conducted in a dark room. To make your eyes easier to examine, you'll generally be told to keep your eyes fixed on something behind the doctor. Not having to read any eye charts means that a retinoscopy exam is also a really useful tool to determine the prescriptions of the speech-impaired, or young children.