Using Ultrasound Biomicroscopy Research Articles

Ultrasound biomicroscopy for localization of artificial lens haptics after trans-scleral suture fixation

Correct positioning of transscleral haptics for sulcus fixation of IOL haptics may be difficult due to lack of visual control by the surgeon. We determined the haptic sites in eyes which underwent secondary IOL implantation with transscleral suturing using ultrasound biomicroscopy (UBM) (Humphrey Instruments, Inc., San Leandro, CA, USA). Eighteen eyes of 17 patients were included in the study. The follow-up time ranged from 1 to 36 months (mean: 7 months). The positions of 36 IOL-haptics were documented by UBM examination. Twelve haptics (33%) were found in the sulcus, whereas 18 haptics (50%) were located posteriorly to the sulcus. Six haptics (17%) were identified anteriorly to the sulcus. There were no complications resulting from dislocation. In one of the eyes, suture infection occurred requiring surgical revision and antibiotic therapy.

Ultrasonic biomicroscopy of viable, dead and apoptotic cells

Ultrasonic imaging is frequently used in medical diagnosis to differentiate normal and tumour tissues. Here we investigate if distinct types of cell death can be discriminated through the use of ultrasound biomicroscopy. By using a well-controlled system in vitro, we demonstrate that this imaging modality can be used to differentiate living cells, dead cells and cells that have died by programmed cell death or apoptosis. The results indicate a greater than twofold ultrasound backscatter signal from apoptotic cells in comparison to viable cells, whereas heat-killed cells exhibit an intermediate level of ultrasound backscatter. The results have potential implications in the study of disease-related biological processes involving apoptosis.

Glaucoma with Inflammatory Precipitates on the Trabecular Meshwork

The syndrome of inflammatory precipitates on the trabecular meshwork is a rare form of inflammatory glaucoma that was described by Chandler and Grant in 1968 and subsequently given the eponym Grant's syndrome. We present two cases of elevated intraocular pressure associated with inflammatory precipitates on the trabecular meshwork in otherwise relatively quiet eyes, consistent with Grant's syndrome. We review the epidemiology, clinical features, and mechanism of this syndrome. In addition, we demonstrate the use of ultrasound biomicroscopy for imaging angle inflammatory precipitates. Our patients demonstrate the cardinal features of Grant's syndrome, including acute onset, significant elevation of tension, trabecular meshwork precipitates in an otherwise quiet eye, limited response to typical pressure lowering agents, excellent response to topical steroids, evidence of recurrence with bilaterality, and systemic association with sarcoidosis. Ultrasound biomicroscopy proves to be a useful adjunct for pathologic imaging. The syndrome of glaucoma with inflammatory precipitates on the trabecular meshwork is a rare entity that should be considered as a possible diagnosis of elevated intraocular pressures in otherwise apparently quiet eyes.

Ultrasound Biomicroscopy in Pars Planitis

To report the diagnosis of pars planitis on the basis of ultrasound biomicroscopy images. The Humphrey ultrasound biomicroscope was used for examination of the right eye of a 17-year-old boy, referred to our clinic because of blurred vision. The lens showed a posterior subcapsular cataract precluding fundus visualization. Ultrasound biomicroscopy showed a homogeneous mass of medium reflectivity over the pars plana. Lensectomy and vitrectomy confirmed the diagnosis. This brief case report points out the utility of ultrasound biomicroscopy in diagnosing pars planitis in cases of media opacities.

Ultrasound Biomicroscopy and Corneal Endothelium in Nd:YAG-Laser Iridotomy

Thirty eyes affected by angle-closure glaucoma that had undergone YAG-laser iridotomy were studied to evaluate variations of central anterior chamber depth, width of the angle, and loss of endothelial cells after laser treatment. These parameters were determined before and after iridotomy: endothelial cell count using a "non-contact" specular biomicroscope, and anterior chamber depth and angle width using ultrasound biomicroscopy (UBM). The width of the iridotomy and the distance of the iridotomy from the scleral spur and from the corneal endothelium were also measured by UBM, after laser treatment. Results confirmed that, after iridotomy, there is not a significant variation in the central depth of the anterior chamber: it goes from 2.02 mm pre-laser to 2.07 +/- 0.38 mm post-laser. There is, however, a statistically significant increase in the angle (P < .001), which goes from 10.69 +/- 8.88 degrees (0.109 +/- 0.07 mm) to 21.03 +/- 11.28 degrees (0.183 +/- 0.09 mm). The mean dimension of the iridotomies was 0.46 +/- 0.13 mm. The mean endothelial cell count was 55.8 +/- 4.08 cells per linear millimeter before laser treatment and 47.01 +/- 5.39 cells per linear millimeter afterward (P <.001). This study confirms that YAG-laser iridotomy leads to a reduction in the average endothelial cell density. The loss of these cells is inversely proportional to the distance of the iridotomy from the endothelium and the scleral spur.

Clinical use of ultrasound biomicroscopy in involutional blepharoptosis

Involutional ptosis is an acquired disorder which is caused by a defect in the levator aponeurosis. Although the histopathologic changes of the levator aponeurosis are well defined in ptotic eyelids, the status of aponeurosis in ptotic eyelids can only be recognized at surgery.Ultrasound biomicroscopy is a high frequency ultrasonography that has the unique ability to image up to 4 mm beneath the surface. The authors applied this technology to ptotic and clinically normal eyelids in order to image the appearance of the levator aponeurosis and its relation with the tarsus. Ultrasound biomicroscopy was also performed postoperatively in order to image aponeurotic re-insertion.Ultrasound biomicroscopy proved a useful method to image the levator aponeurosis. It is helpful not only in the preoperative evaluation of blepharoptosis but also postoperative demonstration of surgical reinsertion.

Ultrasound Biomicroscopy of Anterior Segment Tumors

Ultrasound biomicroscopy is a new method of imaging the anterior segment of the eye at microscopic resolution using high frequency ultrasound. A prospective study was performed to evaluate the use of ultrasound biomicroscopy in imaging anterior segment tumors. Forty-five patients underwent clinical examination followed by slit-lamp photography, anterior segment B-scan ultrasonography, and ultrasound biomicroscopy according to an established protocol. All lesions were clearly imaged by ultrasound biomicroscopy, while only 17 were detectable by conventional B-scan ultrasound. Ultrasound biomicroscopy allowed precise measurement and visualization of subsurface features in small tumors. Differentiation between solid and cystic lesions was easily achieved. The margins of ciliary body tumors could be more accurately defined. Histopathologic correlation was possible in four cases managed surgically. Ultrasound biomicroscopy images compared favorably with low-power microscopy. No complications were encountered. Ultrasound biomicroscopy proved a valuable new noninvasive technique in the evaluation of anterior segment tumors.

Clinical Use of Ultrasound Biomicroscopy

The authors have developed a method of obtaining images of crosssections of the intact anterior globe at microscopic resolution. High-frequency ultrasound transducers (50-100 MHz) have been developed and incorporated into a clinical B-scan device capable of producing images in the living human eye to a depth of approximately 4 mm at an axial and lateral resolution approaching 20 μm. Clinical use of this instrument is no more difficult than conventional immersion ultrasonography. The authors' results in a series of 14 clinical cases have shown that this method can provide information unavailable from any other imaging technique. Anterior segment tumors difficult to define with conventional ultrasound can be measured and the extent of invasion determined. Differentiation of tissue on the basis of internal acoustic characteristics is aided by the very fine backscatter speckle patterns at these frequencies. Pathology behind anterior segment opacities can be imaged in detail and the ability to image angle structures in cross-section allows a new quantitative method of gonioscopy. The ability to define the relationship of the iris, posterior chamber, zonules, ciliary body, and lens is potentially helpful in understanding mechanisms of glaucoma. Ocular structures can be measured with increased accuracy. Clinical ultrasound biomicroscopy (UBM) has shown significant potential as an aid in diagnoses of ocular disease.