The procedure followed for applying the P&R test consisted of all the participants in the study reading (in monocular and binocular vision) the letters located on the optotype
, beginning with the top row and continuing until two of the three letters in the same group were read incorrectly.
Kay Pictures are the most commonly used optotype
test for young children in the UK.
Images included Lea symbols (circle, square, house, or apple; Figure 1(a)), posted on a 15-line vision optotype
However, the testing becomes much easier as the children understand optotypes
and communicate better, and the possibilities for optometric management improve since children become more likely to cooperate with spectacle wear or eye exercises.
3-5 years: Matching optotypes
(use the illiterate E chart, Landolt's C test, Sheridan-Gardener's test, Lea charts).
The 4-m chart used had high contrast Sloan letters and optotypes
were in LogMAR increments.
3) This is perhaps because Snellen VA is measured with high contrast static optotypes
, very unlike natural conditions of the "number plate test", making Snellen VA a poor predictor of a person's ability to meet the legal driving standard.
BCVA with Early Treatment Diabetic Retinopathy Study optotypes
(Precision Vision; La Salle, Illinois) ranged from 20/10 to 20/125; 82 percent were 20/20 or better.
Grating acuity was measured with persons with severe disabilities only if it was not possible to use optotypes
a) The spacing of the optotypes
and the lines follows a geometric progression
One or more sessions with an occupational therapist were devoted to training in reading skills with suprathreshold optotypes
(larger than critical print size) or continuous print materials.
Indeed, logMAR charts such as the Bailey-Lovie chart are advantageous in that task difficulty remains consistent across all levels of acuity, with equal number of optotypes
presented per line, and there is a regular logarithmic progression of acuity such that each line is a scaled version of the preceding line, allowing each individual letter to contribute to the VA measure, increasing the accuracy.