Which method is commonly used to measure the axial length of the eye?

The method commonly used to measure the axial length of the eye is A-scan ultrasound. This technique is particularly effective for obtaining precise measurements of the eye's dimensions, which is crucial for various diagnostic and therapeutic purposes, particularly in preparing for cataract surgery and calculating intraocular lens power.

A-scan ultrasound utilizes one-dimensional echo patterns to generate a single line of information that shows the distances between the transducer and reflective surfaces within the eye, such as the anterior surface of the cornea, the lens, and the retina. The resulting data allows for accurate assessment of the axial length, which is vital in understanding refractive errors and planning treatments.

In contrast, B-scan ultrasound, while used to provide a two-dimensional view of the internal structures of the eye, is not adept at measuring axial length directly. OCT imaging offers detailed cross-sectional images of the retina and can measure retinal thickness but is not primarily intended for axial length measurement. Furthermore, fundus photography captures images of the fundus for examination of the retina and optic nerve but does not measure the dimensions of the eye itself. Hence, A-scan ultrasound is the most appropriate and widely used method for accurately determining the axial length of the eye.