C. Referenced Refractive Measurements Sequence

Whenever visual acuity is measured it is necessary to know the conditions under which it was measured. If the vision was measured with the patient's habitual correction in place, this attribute is used to reference a lensometry measurements SOP instance for the current glasses. If the measurements are of the patient's best-corrected vision, this attribute may reference the SOP instance that describes the correction that resulted in that vision, which may for example be the subjective refraction, or the autorefraction.

This attribute enables a receiver of this SOP instance to identify the results of measurements from a lensometer, autorefractor, or automated phoropter (subjective refraction) that are relevant to interpretation.