section name header

Introduction ⬇

An ophthalmic ultrasound is a noninvasive imaging study that is performed to visualize both normal and abnormal tissues of the eye when no alternative visualization is possible because of opacities caused by inflammation or hemorrhage. This information is valuable in the management of eyes for keratoprosthesis. Orbital lesions can be detected and distinguished from inflammatory and congestive causes of exophthalmos with a high degree of reliability. An extensive preoperative evaluation before vitrectomy or surgery for vitreous hemorrhages is also done. In this case, the vitreous cavity is examined to rule out retinal and choroidal detachments and to detect and localize vitreoretinal adhesions and intraocular foreign bodies. Also, patients who are to have intraocular lens implants after removal of cataracts must be measured for the exact length of the eye (within 0.1 mm).

Procedure ⬆ ⬇

  1. Tell the patient that if a lesion in the eye is detected, as much as 30 minutes may be required to differentiate the pathologic process accurately. Otherwise, orbital examinations can be done in 8–10 minutes.

  2. Instill eye drops to anesthetize the eye area.

  3. Ask the patient to close the eye, apply couplant (ultrasound gel), and place a small, very high frequency transducer on the eye directly, or position it over a water standoff pad placed onto the eye surface. Multiple images and measurements are taken.

  4. Ask the patient to hold very still.

  5. Place a probe gently on the corneal surface.

  6. See Chapter 1 guidelines for intratest care.

Clinical Implications ⬆ ⬇

  1. Abnormal patterns are seen in:

    1. Alkali burns with corneal flattening and loss of anterior chamber

    2. Detached retina

    3. Keratoprosthesis

    4. Extraocular thickening in thyroid eye disease

    5. Pupillary membranes

    6. Cyclotic membranes

    7. Vitreous opacities

    8. Orbital mass lesions

    9. Inflammatory conditions

    10. Vascular malformations

    11. Foreign bodies

  2. Abnormal patterns are also seen in tumors of various types based on specific ultrasonic patterns:

    1. Solid tumors (e.g., meningioma, glioma, neurofibroma)

    2. Cystic tumors (e.g., mucocele, dermoid, cavernous hemangioma)

    3. Angiomatous tumors (e.g., diffuse hemangioma)

    4. Lymphangioma

    5. Infiltrative tumors (e.g., metastatic lymphoma pseudotumor)

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain the purpose, benefits, and procedure of the test.

  2. Instill topical anesthetic drops into the eyes before the examination is performed; this usually is done in the examining department.

  3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Clinical Alert

When a ruptured globe is suspected, an ophthalmic ultrasound should not be performed. Excessive pressure applied to the globe may cause expulsion of the contents and increases the risk of introduction of bacteria

Posttest Patient Care

  1. Instruct the patient to refrain from touching or rubbing the eyes until the effects of anesthetic have disappeared. This type of friction could cause corneal abrasions.

  2. Advise the patient that minor discomfort and blurred vision may be experienced for a short time.

  3. Review test results; report and record findings. Modify the nursing care plan as needed.

  4. Counsel regarding possible further testing and treatment for infection (medical or surgical for detached retina).

  5. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Interfering Factors ⬆ ⬇

If at some time the vitreous humor in a particular patient has been replaced by a gas, no result can be obtained.

Reference Values ⬆

Normal