Which ocular tissue produces A-scan spikes?

The lens is responsible for producing A-scan spikes during ultrasound biometry. In A-scan ultrasound, sound waves are emitted and bounce off different ocular structures, creating distinct echoes that are represented as spikes on the resulting graph. The lens, being a highly reflective structure due to its transparency and curvature, generates a significant echo which appears as a clear spike.

This characteristic is important in the context of determining the eye's axial length, which is essential for calculating appropriate intraocular lens power for cataract surgery or refractive surgery. Each structure in the eye has its own level of reflectivity, but the lens is particularly notable for its strong echo, making it easily detectable in A-scan ultrasound measurements.

Other ocular tissues such as the ciliary body, choroid, and retina also reflect ultrasound waves, but to a lesser extent or with less distinctiveness, which contributes to different patterns in the A-scan output. Thus, these structures do not produce the same prominent A-scan spikes as the lens does.