Ординатура / Офтальмология / Английские материалы / Clinical Ophthalmic Echography_Harrie_2008

EH is a 61-year-old man followed annually at the Veteran’s Administration Hospital for a mild cataract. Different ophthalmology residents on each examination usually saw him as they rotated through the eye clinic. He came in for his annual exam and the resident noted an injected episcleral vessel on the inferotemporal right globe. The visual acuity was 20/40 in this eye, compatible with a moderate degree of nuclear sclerosis and peripheral cortical opacity. Fundus examination was unremarkable but the periphery could not be well visualized because of the peripheral cataract. The patient was referred to the university hospital for echography.

Ultrasound revealed a solid lesion in the area of the inferior ciliary body. The tumor could not be imaged in its entirety because of the peripheral location and the difficulty in angling the probe in the direction of the inferior periphery because of the interference by the superior orbital rim. It was also partly visualized by placing the probe directly at the 6:00 limbus and examining the globe just under the probe, although part of it was hidden in the initial spike (Fig. 329). The reflectivity on A-scan was medium and regular with moderate spontaneous internal vascularity.

Immersion scanning was performed with a 10MHz probe and a solid lesion of the inferior ciliary body measuring 5.5 mm in height by 16 mm in basal diameter was visualized (Fig. 330). The diagnosis of a ciliary body melanoma was made and the patient elected to undergo radioactive plaque therapy after a systemic workup showed no evidence of metastatic tumor.

The differential diagnosis of anterior segment tumors includes such entities as ciliary body cysts,

FIG. 329. Contact B-scan of ciliary body melanoma directly under probe (arrow)

medulloepitheliomas, leiomyomas, and adenomas of the nonpigmented ciliary epithelium.

Cystic lesions are the most common of these entities and are readily detected on immersion imaging

FIG. 330. Immersion scan (10 MHz) of ciliary body melanoma (arrow)

TA is a 43-year-old man who presented to his ophthalmologist with complaints of intermittent pain and blurred vision in his right eye. The visual acuity was 20/20 in both eyes and intraocular pressure was measured to be 21 mm in the right eye and 16 mm in the left. Slit-lamp examination showed narrowing of the temporal angle of the right eye and gonioscopy confirmed a closed angle temporally but a 2+ open angle superiorly, nasally, and inferiorly. The opposite eye had a 2 to 3+ open angle for 360°.

Immersion ultrasound using a 50-MHz probe demonstrated large ciliary and retroiridial cysts that bowed the iris anteriorly and closed the temporal angle (Fig. 333). Because of the chronic nature of the problem in this patient, it was elected to treat him with topical medication to lower the pressure and defer surgical intervention pending uncontrollable pressure from further angle closure.

Focal angle closure can also be a result of epithelial “pearl” formation and retained cortex in the capsular bag. This can create a mass effect with mechanical pressure on the iris that bows it forward and narrows the angle.

FIG. 333. Ultrasound biomicroscopy of ciliary body cyst (bottom arrow) with iris bowing (top arrow)

JE is a 43-year-old man who was born with congenital cataracts. He underwent bilateral lens needling procedures as a teenager. He had vision in the 20/80 range in both eyes until a few months before presentation to an ophthalmologist with complaints of a reduction of vision in his right eye. Examination showed vision of 20/100 in that eye and 20/80 in the left eye. The pupils were under 3 mm, updrawn, and minimally reactive to direct light. Slit-lamp examination showed a bulge in the temporal iris with the appearance of a pigmented mass on transillumination. The posterior pole could be visualized on fundus examination but the peripheral retina and ciliary body could not be seen.

Echography demonstrated the posterior lens capsule with the appearance of a solid lesion arising from it and bowing the iris forward by direct pressure (Fig. 334). This image was consistent with lens epithelium and cortex organized into a retroiridial mass with focal angle closure, but a neoplastic process, such as melanoma, could not be totally eliminated. The patient was instructed to return for repeat immersion scanning in 4 months.

Rare tumors of the anterior segment include adenoma of the iris pigment epithelium that can erode through the stroma and become visible on slit-lamp examination. According to Shields et al.,74 these lesions can be differentiated from ciliary

body melanomas on the basis of transillumination and careful slit-lamp examination with gonioscopy. They have a solid appearance on echography.

Other lesions, such as adenoma and adenocarcinoma of the nonpigmented ciliary body epithelium (NPCE), are acquired, versus medulloepitheliomas, which are congenital tumors derived from the NPCE. Shields states that they can be distinguished from ciliary body melanomas by a complete lack of pigment, lack of setinal vessels, and a generally smaller size than melanomas. The echographic findings are nonspecific.

Rarely, leiomyomas can involve the ciliary body and peripheral choroid. Shields75 reports that they are most common in women in the third decade of life. An important echographic feature in some cases is a normal choroidal layer, suggesting that this tumor is located in the suprauveal space. This fact is significant in the surgical treatment of these lesions. They could potentially be removed from the suprachoroidal space without disruption of the adjacent choroid with a good visual result.

Anterior segment tumors can be simulated by very peripheral views of a cataractous lens. When the B-scan probe is placed on the temporal sclera and angled very anteriorly, the opacified crystalline lens can be imaged with the artifactual appearance of a tumor.

AM is a 75-year-old woman who was scheduled for cataract surgery on a 4+ nuclear sclerotic lens. The ophthalmologist had difficulty visualizing the fundus and performed a B-scan examination. When the probe was placed on the posterior temporal sclera against the orbital rim and aimed towards the cornea, a dome-shaped mass was imaged (Fig. 335). The diagnosis of a probable ciliary body melanoma was made and the patient was referred to an oncologist to be evaluated for systemic metastases. The workup was negative for tumor and a discussion was instituted regarding treatment options, including enucleation. This greatly concerned the patient and she sought a second opinion.

Immersion echography was performed and a dense cataractous lens was imaged but no mass lesion was identified (Fig. 336). The diagnosis of a lens artifact simulating a tumor was discussed with the patient to her great relief.

This situation is relatively common with different appearances of the lens/tumor artifact (Fig. 337). Helpful clues to eliminate a tumor include the inability to image the lesion when the probe is placed on the sclera directly over the area of the “tumor,” the symmetrically round shape, and the absence of subretinal fluid. If the diagnosis remains in doubt, then an immersion scan can be performed that will

FIG. 335. B-scan with peripheral view of cataractous lens (arrow)

demonstrate a cataractous lens and the absence of a tumor.

Another lens tumor-simulating artifact is a dislocated cataractous lens that rests on the posterior retina. This can be particularly deceiving in a patient with opaque media, such as a cloudy cornea in which the presence or absence of the lens in its normal retroiridial position cannot be determined on slit-lamp examination.

CD is a 43-year-old man with a history of a serious infection in his left eye years ago that resulted in some decreased sight in that eye. His vision had decreased slowly since that time and was very poor at the time of presentation to an optometrist. Examination found vision in that eye of counting fingers at 1 m and 20/30 in the right eye. Slit-lamp examination showed scarring of the right corneal stroma with a poor view of the anterior chamber and lens.

The fundus could not be visualized, so B-scan was performed with the appearance of a mass near the inferior equator. There was substantial shadowing of the globe and orbital tissue directly behind the lesion (Fig. 338). This lesion was solid with low internal reflectivity on A-scan (Fig. 339).

FIG. 338. B-scan of dislocated cataractous lens (arrow)

FIG. 339. A-scan of dislocated cataractous dislocated lens (arrows)

However, when the patient was asked to move his eye the lesion rolled along the fundus to a new position with the resultant diagnosis of a dislocated lens and the patient was reassured that he did not have cancer. It was elected to defer treatment unless he decided at some point to undergo penetrating keratoplasty. A combined procedure with a fragmatome lensectomy and vitrectomy would then be the operation of choice.

Echography plays a very important role in the evaluation of various intraocular and peribulbar lesions. It can detect and differentiate various lesions with greater accuracy than any other imaging modality. The performance of this technique by a properly trained examiner will prove invaluable in the clinical setting.

Ophthalmic echography can play a unique role in the clinical practice of ophthalmology in emerging and developing countries. These areas often have limited access to imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI) scanning. The multiple obstacles to utilization of these modalities for the average patient include cost, waiting time, travel distance, and cultural barriers. The availability of echography in the eye clinic can directly impact the quality of care in these countries.

Ocular and orbital pathology usually is not very different from that seen in more developed parts of the world, but it often presents at advanced stages that render diagnosis and treatment more difficult. It is common to encounter mature “white”

cataracts, large corneal scars, advanced glaucoma, end-stage vitreoretinal pathology, and marked proptosis. Such conditions have often been present without treatment for long time periods because of the lack of medical resources in the local area.

Eye trauma with concussive or penetrating injuries is frequently not treated in a timely fashion, which can result in globe abnormalities that preclude adequate visualization of the posterior segment. The potential to enhance the patient’s quality of life with available resources is inversely proportional to the complexity of the pathology. Ultrasound can rapidly screen out those who are not realistic candidates for therapeutic intervention. The patient can be advised as to his prognosis after an echographic examination that takes only a few minutes to perform.