ETDRS Chart 1, one of the three logMAR chart models designed by Ferris, Kassoff, Bresnick, and Bailey for use in the Early Treatment Diabetic Retinopathy Study (ETDRS).

Chart and optotype dimensions in millimeters precisely as specified by Ferris et al. (1982).
LogMAR and VAR values after Baliey &amp; Lovie (2013).
Note: meters/feet not a direct conversion, but rather in Snellen equivalents (1 meter = 5 feet).
Own work, after

Ferris FL, Kassoff A, Bresnick GH, Bailey IL (1982). "New Visual Acuity Charts for Clinical Research". American Journal of Ophthalmology 94 (1): 91–96. DOI:10.1016/0002-9394(82)90197-0. ISSN 00029394.
Ferris FL, Freidlin V, Kassoff A, Green SB, Milton RC (1993). "Relative Letter and Position Difficulty on Visual Acuity Charts from the Early Treatment Diabetic Retinopathy Study". American Journal of Ophthalmology 116 (6): 735–740. DOI:10.1016/S0002-9394(14)73474-9. ISSN 00029394.
Bailey IL, Lovie-Kitchin JE (2013). "Visual acuity testing. From the laboratory to the clinic". Vision Research 90: 2–9. DOI:10.1016/j.visres.2013.05.004. ISSN 00426989.
Sloan letters from [1] (public domain).
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