Application of Ultrasound Examination in Ophthalmology

Application of Ultrasound Examination in Ophthalmology

Ultrasound examination is a common auxiliary examination in ophthalmology. It is a diagnostic method that utilizes the reflective properties of sound energy to form images, allowing observation of the body's anatomical structures and pathological conditions. Ophthalmologists commonly use three types of ultrasound: A-mode, B-mode, and D-mode.

A-mode ultrasound: Utilizes 8-12MHz ultrasound waves to display the echoes (reflection curves) of each acoustic interface of the probed tissue. These echoes are arranged sequentially on a baseline in the form of peaks, according to the time sequence of their return to the probe, forming a one-dimensional image aligned with the direction of detection. Its advantages include precise distance measurement and quantification of echo intensity.

It is commonly used to measure axial length, aid in calculating the intraocular lens power during cataract surgery, and assist in the diagnosis of conditions such as congenital microphthalmia and congenital glaucoma.

Specific A-mode ultrasound can also be used to measure corneal thickness.

B-mode ultrasound: Through fan-shaped or linear array scanning, it converts the reflected echoes from interfaces into light spots of varying sizes and brightness, displaying a two-dimensional acoustic image composed of numerous echo spots. The brightness of light spots represents the intensity of echoes. The numerous points formed by these echoes create a real-time two-dimensional acoustic cross-sectional image on the oscilloscope screen, extending from the iris to the posterior segment of the eyeball.

D-mode ultrasound, also known as Doppler ultrasound, is primarily used for examining blood vessels and blood flow.

Common abnormal findings in ultrasound examinations include abnormal intraocular echoes and orbital abnormalities.