Which type of A-scan is used for most axial eye length measurements?

The conventional A-scan is the method primarily employed for axial eye length measurements in ophthalmic ultrasound because it provides a straightforward and comprehensive representation of the signals reflected from various structures within the eye. This type of scanning allows for precise measurement of the distance from the cornea to the retina, which is critical for determining the length of the eyeball when planning cataract surgery or other intraocular procedures.

Conventional A-scans utilize a simple one-dimensional representation of the echoes returned from the different interfaces within the eye, facilitating accurate distance measurements. The technique captures the timing of echoes in relation to the speed of sound in the eye's tissues, resulting in reliable and reproducible axial length measurements.

The effectiveness and reliability of the conventional A-scan have made it the standard method for clinical practice, ensuring that practitioners can achieve consistent results across patient populations. Additionally, the simplicity of the A-scan format makes it user-friendly for ophthalmic sonographers, enhancing its widespread adoption in clinical settings.