We've all been told to place our right hand over our right eye and read “line 10 from left to right”. This classic eye test is based off of the Snellen eye chart developed in the 1860s by a Dutch eye doctor named Hermann Snellen. To this day, we have many more technologies that allow us to test other parts of the eye; however, still, almost all of our comprehensive eye exams involve some form of the Snellen eye chart test as well. While this chart plays a big role in one's eye exam, it can only text visual acuity, and therefore, other tests must usually be done to determine peripheral vision acuity, degrees of color blindness, contrast perception, or depth perception.
The Snellen eye chart was such a simple, yet productive invention! Due to the ease of using it and clarity of the results, doctors haven't found a reason to replace it with any of the other exams they constantly use. However, with this, does come certain alterations made throughout the years. For instance, besides the signature alphabetical chart, there is also a variation called the “tumbling E chart”. This is mainly directed at small children whom don't know the alphabet yet or are too shy to list them aloud, or perhaps those suffering from some sort of disability refraining them from knowing or understanding the shapes. The purpose of the tumbling E test is that the patient is able to use their first three fingers to illustrate the exact figure they see at that moment. After extensive research, it has been found that this test is just as accurate as the actual Snellen eye chart test, and therefore will too be continued to be used.
What is one of the biggest reasons that this test is used more than any other optical exam? Most likely, it is to due with the inexpensive price to conduct it. While new technologies bring higher tech options and advantages, it's nearly impossible to beat something that is just as good, for a fraction of the price! For instance, the Snellen eye chart is what is typically used within schools for all of the free optical exams for young school children. Instead of lugging lots of heavy, expensive medical tools, they can easily bring in this chart and get a better understanding of their clients needs.
Even with all of the high tech inventions that are constantly being discovered and produced, the Snellen eye chart plays a large part of your complete eye exam. This simple chart can help determine whether or not you'll actually need prescription glasses. Just by concluding your visual acuity, your doctors will be able to determine whether or not your have a need for glasses, and if so, this chart can help promote your needs for your new eyeglasses prescription. So, if you haven't done so in quite a while, go get your eyes checked, and surprise your doctor with all you know about the Snellen eye charts!