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The History & Accuracy of the Snellen Chart
I understand if the title throws you off- “what is a Snellen chart and why should I care?” That was my first response too- and I actually work in an Optometry office. (I’m not a Optometrist, but I could totally play one on TV.)
The Snellen Chart is that screen of weirdly shaped block letters that you read when you have an eye exam. It’s been in use for over 150 years and the standardization of the chart is what has allowed for accurate testing when you get an exam. What most of us don’t understand is why the chart is made like it is; there’s a bunch of math that they explain about why and how it those letters are used. This video is a pretty cool lesson about the chart’s history and what those numbers like 20/20 really mean. It’s only 5 minutes long and I learned a couple of things.
Now, if you’ve been in to our office within the last few years, you realize that all of our Snellen charts are projectors that are connected to a little brain unit that controls everything from the chart to the phoropter and connects to our Electronic Medical Records. As the video says, visual acuity is only one part of the entire exam. Our system helps integrate all of those other exams too. After all, a paper chart just doesn’t cut it anymore.
