A-scan ultrasound biometry
Template:Short description Template:More medical citations needed Template:Infobox diagnostic A-scan ultrasound biometry, commonly referred to as an A-scan (short for Amplitude scan), uses an ultrasound instrument for diagnostic testing.<ref name="w128">Template:Cite journal</ref> A-scan biometry measures the axial length (AL) of the eye prior to cataract surgery in order to assess the refractive power of the intraocular lens that will be implanted.<ref name="b066">Template:Cite journal</ref>