Talk:Sloan letters

Added Typography template.
It turns out that Sloan letters are available as computer fonts for both the MAC and Windows, so I am concluding that this article should have a WikiProject Typography template.--DThomsen8 (talk) 01:53, 28 October 2009 (UTC)

Second of arc????
That can't be right. Surely it should be minute of arc.

And something needs to be fixed in the wording, because it doesn't make sense that a chart invented in 1862 would use letters invented in 1959. Dpbsmith (talk) 22:27, 20 September 2010 (UTC)

I actually don't understand the language used: These optotypes are used because they differ from another optotype by 1 second of arc at a constant distance and size, so that all letters will be about as likely to be recognised.

I'm trying this, because this is I understand the cited reference, http://www.uniroma2.it/otticafp/va.html (which also confirms that the acuity standard is one minute of arc, not one second):
 * These letters, unlike the ones used in older Snellen charts, are designed to give acuity testing results that are comparable to tests made using Landolt broken rings.

Dpbsmith (talk) 22:40, 20 September 2010 (UTC)


 * The edit is fine. However, since the term "Landolt broken ring" is rarely used, I replaced it with the more familiar "Landolt ring". Strasburger (talk) 14:41, 12 July 2022 (UTC)

Pay attention with letter D on the image!
Letter D is not the true D Sloan Letter. This is a big mistake!

You can find the original Sloan D in her original paper: SLOAN LL. New test charts for the measurement of visual acuity at far and near distances. Am J Ophthalmol. 1959 Dec;48:807-13. doi: 10.1016/0002-9394(59)90626-9. PMID: 13831682. Reference that is not cited in the Wikipedia article. Shisheta (talk) 10:14, 5 February 2024 (UTC)