Sam Mauchlen MRCVS BVM&S
Ultrasound is used routinely by veterinary ophthalmologists to evaluate ocular and orbital structures. Ultrasonographic assessment of eye facilitates the examination of intraocular structures in cases where pathology is obscuring the normal anatomy and can aid in the detection and evaluation of intraocular conditions such as neoplasia. Additionally, ultrasound can be used to examine the structures within the orbit and retrobulbar space.
Patient preparation and technique
As the ocular structures are superficial, appropriate ultrasound transducer selection and optimising the ultrasound machine set up is important. Medium to high frequency transducers capable of producing ultrasound frequencies of 12 – 20MHz are ideal for ocular ultrasound. However, lower frequency transducers (or a reduced ultrasound frequency setting) can be used to examine the posterior globe and retrobulbar tissue. The depth setting on the ultrasound machine should be altered so that the area of interest occupies 75% of the screen and the focal zone(s), which represents the area of optimal lateral resolution, should be positioned at the level of the area of interest.