The primary application of A-scan biometry is to calculate the power of what type of implant?

A-scan biometry is primarily used to calculate the power of intraocular lenses (IOLs) that will be implanted during cataract surgery. This technique utilizes ultrasound to measure the axial length of the eye, which is crucial for determining the appropriate lens power needed to achieve optimal vision post-surgery.

Intraocular lenses replace the eye's natural lens when it becomes cloudy due to cataracts, and precise measurements are essential to ensure that the new lens focuses light correctly on the retina. By providing accurate axial length measurements alongside the corneal curvature, A-scan biometry helps surgeons select the most suitable lens power, improving surgical outcomes and the patient’s quality of vision.

Other options such as corneal transplants, retinal implants, or contact lenses involve different considerations and methods for planning and fitting, making them unsuitable for A-scan biometry's primary application. For example, corneal transplants focus more on the health of the cornea rather than lens power calculations, while contact lens fitting involves different measurements altogether that do not require A-scan biometry.