The ultrasound scanning is a biometry and imaging examination using an ultrasound sound beam. On one hand, it makes possible measuring the different eye-structure lengths (axial length, cornea or crystalline lens thickness) and on the other hand rebuilding a 2D view (section) of the eye, particularly the fundus (retina). It can also be used to observe the tissues around the eye and the orbit.
It is mainly used when the eye internal media are not transparent enough (dense cataract, haemorrhage, inflammations, etc.) and prevent the light from going through (used by optical biometers or slit lamps).
Depending on the examination mode, there is a contact with cornea (echo A) of the eyelid (echo B). The doctor has to be careful to correctly perform the examination. Using a different probe, it is also possible to measure the cornea thickness, as it a precious value to follow-up glaucomas or detect some pathologies. In this case, the probe is applied on the cornea.