Snellen test type

Snel·len test type

(snel'ĕn test tīp)
One of a series of square black symbols employed in testing the acuity of distant vision; the letters vary in size in such a way that each one subtends a visual angle of 5' at a particular distance.
References in periodicals archive ?
At the time of presentation, best corrected visual acuity recorded was 6/6 in RE and FC at 3 m in LE (Snellen test types).