What is the maximum axial resolution in A-scan ultrasound?

In A-scan ultrasound, the maximum axial resolution is influenced by the wavelength of the ultrasound waves used and the characteristics of the transducer. Axial resolution refers to the ability to distinguish between two points along the axis of the ultrasound beam. A smaller axial resolution means that two closely spaced structures can be separated more effectively.

The correct answer of approximately 0.1 mm represents the theoretical limit of axial resolution achievable with high-frequency transducers typically used in ophthalmic ultrasound. Higher frequencies yield shorter wavelengths, which directly translate to finer resolution capable of distinguishing minute structures within the ocular anatomy. Therefore, advancements in transducer technology and beamforming contribute to this high level of axial resolution, allowing for precise measurements in diagnostics.

In contrast, the other values provided in the answer choices represent less optimum axial resolutions, which might be relevant for lower frequency ultrasonography or in different contextual applications outside of high-resolution eye assessments.