Eyes and Vision
Vision Testing Methods
Best corrected visual acuity measurements should be made with each eye individually and then with both eyes open. Methods and testing materials should be according to the Consilium Ophthalmologicum Universale standard on visual acuity measurement, i.e., the Snellen Chart, NEI Sloan Chart (ETDRS), Landolt C, Illiterate E on Charts, or in a visual screener device.
If it is necessary to measure visual fields, this should be done with a formal perimeter (as opposed to confrontation which is highly insensitive to defects).
It is critical for color vision testing to be done with the correct illumination and designated by the manufacturer of the testing device.24 The Task Group does not make a recommendation of which instrument to use for screening for color vision defects, but does note that Ishihara PIP tests are more common than others in the United States.