Principles of ophthalmic ultrasound

ABSTRACT

Introduction

Ultrasound imaging of the eye was introduced over 50 years ago. While the physical principles of ultrasound imaging have not changed, technology has undergone tremendous and ongoing development.

Areas covered

The fundamentals of ultrasound physics, biometry (A-scan), structural imaging (B-scan), and blood-flow imaging and measurement (Doppler) will be described. Emphasis will be placed on technological development and potential future advances.

Expert opinion

While A- and B-scan ultrasound of the eye has traditionally been performed with focused single-element transducers, the introduction of annular and linear arrays has enhanced clinical utility. Future advances, especially in multielement arrays, and point-of-care systems promise amazing new capabilities for diagnostic imaging of the eye and orbit.

KEYWORDS:

• Ultrasound
• eye
• Doppler
• transducer
• resolution

Article highlights

• Medical diagnostic ultrasound developed in the aftermath of the second world war as a spinoff of Sonar technology used for underwater range finding.

• While ophthalmic ultrasound has largely been based on mechanically scanned, focused single-element transducer technology, virtually all other clinical specialties use linear array-based systems.

• Array-based systems allow control of focal depth. Linear arrays offer high scan rates and can provide Doppler to visualize and measure blood-flow.

• The advantages and decreasing cost of linear array systems are leading toward greater utilization for ophthalmic imaging.

• While the principles of ultrasound imaging are unchanged, the technology, especially in array-based systems, continues to advance.

Declaration of interest

R H Silverman has a financial interest in Arcscan, Inc. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was funded by NIH grants R01 EY025215, R01 EB032082, P30 EY019007 and an unrestricted grant to the Columbia University Department of Ophthalmology from Research to Prevent Blindness.