What should be used to ensure proper coupling between the transducer and the eye during an exam?

The use of coupling gel is essential for ensuring proper acoustic coupling between the transducer and the eye during an ophthalmic ultrasound exam. Coupling gel is specifically designed to eliminate any air gaps between the transducer and the surface being examined, which is critical for the effective transmission of ultrasound waves.

Air can significantly interfere with ultrasound propagation, leading to poor image quality or inadequate visualization of the eye structures. Coupling gel, being water-based, allows for optimal conductivity of sound waves, thereby enhancing the quality of the ultrasound images obtained.

While other substances like normal saline or ophthalmic ointment may have some fluid properties, they are not specifically formulated for ultrasound applications. Alcohol swabs are used for disinfection and are not compatible with ultrasound coupling. The use of coupling gel, therefore, is pivotal for achieving accurate and clear ultrasonic imaging, making it the most appropriate choice for this situation.