Expanded Snellen

[JMartinC4]

While sitting at my desk reading my Snellen and the small print on my World Map, I realized that a problem with the Snellen chart(s) is that it needs more increments. It has increments of 4 ft, 7 ft, 10 ft, 15 ft, 20 ft, 30 ft, 40 ft and 50ft (I cut off the 60 ft and 70 ft lines). I can consistently induce clear flashes to read the 10 ft, some of the 7ft, and sometimes even the 4 ft lines (my chair is about 6ft from the wall). However, the smallest printing that I can consistently read on the map is between the 7 ft and 10 ft sizes. Since myopia is much more variable than 2 ft increments, I think it would be helpful to have a Snellen chart that was broken out in .5 foot increments. Does that kind of chart exist somewhere?