What do people think of when they hear the names Hermann Snellen and Steve Jobs? Jobs is obvious, but Snellen, not as much. Yet they were both visionaries, so to speak, in their respective fields.
The Netherlands is justifiably well known for beautiful tulips, picturesque windmills along the countryside and of being the birthplace of Vincent Van Gogh.
What many people are unaware of is that the Dutch country is also native land to an invention without which much of the world would be unable to fully appreciate Van Gogh’s artistic masterpieces: The eye exam chart.
In 1862 Hermann Snellen, an ophthalmologist, eye surgeon and professor, developed what would eventually become known as the Snellen chart to measure a person’s visual ability against a common industry standard. Prior to Snellen’s groundbreaking invention, eye doctors were dependent on reading tests from the limited fonts that were available at the local print shops.
This method was problematic because there was no common touchstone to test the exact refractive error in an individual patient’s eyes. Snellen’s chart allowed ophthalmologists to streamline the process and to much more accurately pinpoint how far a patient’s visual acuity deviated from what would eventually become known as the 20/20 standard.
Of course, as with any pioneering invention, there have been innovations and improvements. Today many eye doctors utilize a slight variation to the Snellen Chart known as the LogMAR Chart which was conceived and developed by Ian Bailey and Jan Lovie in 1980 at the National Vision Research Institute of Australia.
The LogMAR chart differs from the Snellen chart in that the sizes of the letters on the chart progress systematically in a geometric progression with the same number of letters on each line. This improvement allows for a more consistent sampling of visual acuity between lines. Regardless, no matter which of these two eye charts hangs in your doctor’s office, the myopic of the world owe a resounding thanks to Hermann Snellen for an invention that has improved the quality of life for millions of people.