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.
LogMAR, the logarithm of the minimum angle of resolution, refers to the angular size of the optotype
that can just be discerned.
A pediatric ophthalmologist performed a complete ophthalmologic examination, which consisted of visual acuity evaluated by Snellen or Allen optotype
recognition, Teller visual acuity, or assessment of fixation reflex; measurement of ocular alignment in primary gaze at both distance and near using the alternate and simultaneous prism cover tests; and evaluation of pupils for anisocoria and afferent defects.
In the study, they used the Arden colour contrast test index (ACTI), measuring the contrast threshold in percent between the presented optotype
and the surrounding area.
Visual acuity (VA) was determined using Snellen optotype
, from the distance of 6 meters, in the light of constant brightness and with best refractive correction.
* Contrast sensitivity was tested using appasamy contrast sensitivity chart at 6m distance 'optotype
was equivalent to 6/12 snellen visual acuity.
Visual acuity of eligible subjects was measured with a tumbling Snellen "E" chart with a size 200 optotype
on one side and a size 60 optotype
on the other, at a distance of 10 or 20 feet, inside or in front of study participants' houses, in daylight.
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were the first to develop a cDVA by flashing the letter E optotype
whenever head velocities were between 120 and 180[degrees]/s .
Lambert, "Association between occlusion therapy and optotype
visual acuity in children using data from the infant aphakia treatment study: a secondary analysis of a randomized clinical trial," JAMA Ophthalmology, vol.
Enrolled subjects underwent unaided visual acuity testing for distant vision using snellen's chart and near vision Optotype
The participants' best-corrected distance acuity was measured using a rear-illuminated Snellen chart at 6 meters (about 20 feet, or closer if the participant was not able to read the 6/60 optotype
) and converted to LogMAR notation for the purposes of analysis.