There are generally two types of ultrasonic diagnostic devices used by ophthalmic professionals: A-Scan and B-Scan instruments.

Since the introduction of this technology in the mid-twentieth century, great advances have been made in the equipment. Keeler Instruments has remained on the forefront of this change. Continue reading to learn more about the A-Scan vs B-Scan technology available to diagnose and treat a variety of eye diseases.

What Is ultrasonic imaging?

Because the human eye is essentially a ball of fluid, A-Scan and B-Scan ultrasound technology offers an effective means viewing the eye. Ultrasonic waves bounce back from tissue within, and dimensional measurements help ophthalmologists provide proper diagnoses. Ultrasonographic imaging is essential to a variety of diagnoses and treatments.

Which technology is best for you? This depends on what you need to do for your patients. Typically, hospitals and eye specialists use both for various purposes in conjunction for a complete diagnosis, pre-surgery preparatory scan, or post-surgery follow-up.

Let’s take a closer look at the key differences in A-Scan vs B-Scan.

What is A-Scan ultrasound technology?

A-Scan technology refers to amplitude scanning, based on timed echoes. In A-Scan, a single, one-dimensional beam of sound waves generated at 8 MHz are converted into spikes, which correspond with tissue and correspond to the height of the echo.

The results provide specialist measurements that help diagnose retinal detachment, choroidal melanoma and more. (With A-Scan, coupling jelly is not necessary.) The echoes from the single-beam A-Scan help specialists explore tissue densities, as determined by the spike height from the scan. This in turn helps characterize internal structure of eye tissues and tumors.

A-scan technology — like A-Scan Plus Connect and A-Scan Plus Connect Probe — are most commonly used for measuring the axial length (AL), which is key for intraocular lens calculations leading up to cataract surgery. Another application of A-scan is ascertaining ultrasonic properties (such as internal reflectivity) and the sizes of posterior segment masses in the eye. This is often used in conjunction with B-scans to differentiate lesions.

What is B-Scan ocular technology?

B-Scan technology refers to brightness scan, and can be performed directly on an anesthetized eye. For trauma cases or for children, B-scan can be performed over the eyelid with coupling jelly. With B-scan, two-dimensional sound waves are generated at 10 MHz or higher.

This technology is typically used for evaluating posterior segments and orbital pathology, especially in patients where the ocular media are clouded over and direct viewing is not an option. Like A-scan, B-scan can also be used to diagnose retinal or choroidal detachment as well as foreign bodies, calcium, and tumors.

A-Scan vs B-Scan – what are the essential and important differences?

A-Scan has the ability to characterize internal tumor structure and composition based on the aforementioned data. B-scan is useful in emergency rooms and in post-surgery check-ups due to its two-dimensional detailing.

However, the essential difference is in the dimensions:

  • A-scan uses a single one-dimensional beam to determine the density of whatever structure it’s aimed at. Diagnoses can be made if you’re aiming right at something you are specifically looking at.
  • B-scan uses a two-dimensional array of one-dimensional A-scan beams (generated at higher MHz frequencies) to both determine density and produce useful images.
A variety of ophthalmological pathologies can be diagnosed with either scan type. Ocular ultrasound systems can come as separate components or self-contained setups.

4Sight ultrasound

In addition to A-Scan and B-Scan, Keeler also offer 4Sight; a portable ultrasound screening system tailored for you. The easy-to-set-up, modular platform allows tailoring to suit your specific needs, while its proprietary software delivers an intuitive user interface and easy data transfer between modalities, meaning more time with your patients and less with the manual.

Contact Keeler

Any practitioner typically would do well to be prepared for both A-scan and B-scan. Instead of looking at the A-Scan vs B-Scan, it’s best to view these technologies as complementary. Together, you can use the A-scan and B-scan technology to provide full and complete treatment of a patient’s pathologies.

As a leader in ophthalmic equipment, Keeler offers a wide range of both A-scan and B-scan technologies.
Contact Keeler today for both A-Scan and B-Scan instruments.