How are axial length measurements obtained in ultrasound?

The correct approach to obtaining axial length measurements using ultrasound involves high-frequency sound waves that are transmitted through the ocular tissue. In this method, a specialized ultrasound probe emits sound waves that penetrate the eye. As these sound waves travel through different tissues (such as the cornea, aqueous humor, lens, vitreous body, and retina), they encounter various interfaces that reflect some of the sound waves back to the probe. The time taken for the sound waves to travel to these interfaces and back is measured, allowing clinicians to calculate the distances and thereby the axial length of the eye.

This method is advantageous for its precision and effectiveness in measuring axial length, which is crucial for determining the appropriate power of intraocular lenses, especially in cataract surgery and refractive surgery planning. The use of high-frequency sound waves is essential for achieving the required resolution and accuracy in these measurements.