Jaeger chart on different Jaeger cards currently in use is very high. Therefore, test results with different Jaeger cards are not comparable. More commonly, distance vision acuity is tested using the Snellen chart, familiarly seen wall mounted with a large letter at the top. Jaeger chart The Jaeger chart is an eye chart used in testing near vision acuity. It is a card on which paragraphs of text are printed, with the text sizes increasing from 0.37mm to 2.5mm. This card is to be held by a patient at a fixed distance from the eye dependent on the J size being read.
Three letter rule Three letter rule In English spelling, the three letter rule (or short word rule) is the observation that one- and two-letter words tend to be function words such as "I", "at", "he", "if", "of", "or", etc. As a consequence of the rule, "content words" tend to have at least three letters. In particular, content words containing fewer than three phonemes may be augmented with letters which are phonetically redundant, such as "ebb, "add, "egg, "inn, "bee, "awe, "buy", "owe", etc. Many content words would be homographs of common function words if not for the latter's "redundant" letters: e.g. "be/bee", "in/inn",