Differences between Recognition and Resolution Acuity in Patients Undergoing Macular Hole Surgery

  • Walter Wittich, Olga Overbury, Michael A. Kapusta, Donald H. Watanabe
  • Investigative Opthalmology & Visual Science, August 2006, Association for Research in Vision and Ophthalmology (ARVO)
  • DOI: 10.1167/iovs.05-1307

Eye charts with letters versus rings do not measure visual acuity the same way

Photo by Vanessa Bumbeers on Unsplash

Photo by Vanessa Bumbeers on Unsplash

What is it about?

Most people are familiar with eye charts that display letters. There are other charts that have rings with a gap at different orientations, which can be used with persons that cannot read or speak; however, visual acuities that are measured with letters are often better than those measured with rings because people are better at guessing a letter from the context of its lines and circles.

Why is it important?

Studies that involve visual acuity across the globe are often compared with one another, but this only makes sense of the different measurement techniques are actually comparable. Many Asian and African countries use rings or tumbling E letters to test vision because participants only need to indicate a direction, and not need to be able to read a specific alphabet.


Dr Walter Wittich
Universite de Montreal

I very much enjoyed designing this study and writing this article, as it was the first time I engaged in research that evaluated a surgical outcome in an ophthalmology setting. It was a great learning experience and I am very glad that is was accepted for publication in a good journal.

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The following have contributed to this page: Dr Walter Wittich