Nov 8 2011

Walking Down Memory Lane: 1st Eye Chart Standardization Efforts

Written by P. Kay Nottingham Chaplin, Ed.D.
1 comments
- Categories: Eye Chart History | Eye Charts | Good-Lite | LEA Symbols | Preschool vision screening | School vision screening

Standardized eye charts help to ensure the visual acuity task is equal on any line of an chart. Though one of the earliest attempts at eye chart standardization occurred in 1835 or 1836 (no . . . this is not a typo), many front line screeners today—more than 175 years later—use eye charts that are not standardized.

Heinrich Küchler, a physician from Darmstadt, Germany, is credited with creating the first symbol eye chart in 1835 or 1836 (Runge, 2000). In a creative effort, Küchler cut small figures from calendars, think almanacs, and glued the figures to paper in decreasing size. Figures included people, cannons, guns, birds, farm equipment, camels, and frogs.

Though possibly pleased with his attempts, Küchler, however, noted two challenges with his symbol eye chart. First, his figures lacked consistency in size. By the way, as a side trip (and many of you who have heard me present know that I am quite notorious for taking side trips), if you look closely at the optotypes on the Kindergarten Eye Chart (a.k.a. “Sailboat” chart), you will notice that the optotypes are inconsistent in size. Look specifically at the hand and star on the 20/30 line.

Kindergarten Eye Chart

Küchler also noted that the frogs, camels, and other figures in his eye chart lacked uniformity in optotype legibility or discriminability. Equal optotype legibility was discussed as one of six components of a standardized eye chart in earlier blog entries. What does this mean? When optotypes lack legibility consistency, some optotypes are easier to distinguish, or even guess, at different points of an eye chart, even on the same line.

Apparently not one to give up pursuing his standardization goal, Küchler, 7 or so years later, published an eye chart using letters arranged in a graduated series. The eye chart consisted of 12 lines with larger letters on the top line. Lines decreased in size to the bottom line. Though the concept remains with us in 2011, Küchler’s chart was not a hit. It was published only once in 1843.

Kuchler Eye Chart
Photo from Colenbrander (2008)


If you want to ensure that Küchler did not waste his time, thoughts, creative energy, or dull his scissors to no avail, use a standardized eye chart. Two choices for screening the vision of all ages include Sloan Letters for older children

Sloan Letter Chart

and the 10-line LEA Symbols eye chart

LEA Symbols Chart

for younger children who do not yet know their letters.

CALL TO ACTION: If you recently switched from a non-standardized eye chart to a standardized eye chart, we would love to hear from you either in the comments below or offline via e-mail to kay@good-lite.com When you respond, please tell us the following:

  • Non-standardized chart used
  • Standardized chart now using
  • Good referrals vs. bad referrals with the non-standardized chart
  • Good referrals vs. bad referrals with the standardized chart

REFERENCES:

Colenbrander, A. (2008). The historical evolution of visual acuity measurement. Visual Impairment Research, 10, 57-66.

Runge, P. E. (2000). Eduard Jaeger’s test-types (Schrift-Scalen) and the historical development of vision tests. Transactions of the American Ophthalmological Society, 98, 375-438.

Comments

ian cheong

ian cheong wrote on 03/21/15 8:00 PM

Colenbrander's paper:
http://www.ski.org/Colenbrander/Images/History_VA_Measuremnt.pdf

Runge's paper:
europepmc.org/articles/PMC1298236/pdf/taos00001-0371.pdf?

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