Ultrasound examination of the eye and orbit is used in situations when it is not possible to evaluate intraocular structures by direct observation or when there is a suspicion that the problem is located behind the eye (in the orbit). This is a particularly important examination in dogs with cataracts.
Due to the opacity of the lens, ultrasound can give us information about the condition of the lens (whether the lens capsule is swollen or ruptured), as well as whether the vitreous has changed or retinal detachment has occurred, all of which are considered when we make a decision about cataract surgery.
We also use a special form of ultrasonography – high-frequency ultrasonography to detect initial abnormalities in the front of the eye in time. These changes in the anterior part of the eye can lead to impaired drainage of ocular fluid (aqueous humor) from the eye and a consequent increase in intraocular pressure and loss of vision. An ultrasound of the eye is performed after a local anesthetic is instilled into the eye, in order to reduce the discomfort of this otherwise non-invasive examination technique. If the pet is too upset, mild sedation is sometimes necessary to perform the examination.