New technology for examining the anterior segment by ultrasonic biomicroscopy
To compare the comfort levels and measurement accuracy of the open-shell technique and a bag/balloon technology (ClearScan, ESI) in anterior segment ultrasound biomicroscopy.
Department of Ophthalmology and Visual Science, Robert Cizik Eye Clinic, University of Texas Medical School at Houston, Houston, Texas, USA.
In this prospective investigation, 20 subjects stated their preference and rated comfort (0 best to 5 worst) for the open-shell technique versus the bag/balloon technology. Three anterior chamber depth and sulcus-to-sulcus measurements were obtained, and the mean for each structure was taken as datum for each subject. Order presentation between the 2 methods was randomized. Pairwise t tests and linear regression analysis were used to determine statistical differences.
One hundred percent of the cohort preferred the bag/balloon technology to the traditional open-shell technique. The mean comfort score was 0.40 +/- 0.53 (SD) and 2.95 +/- 0.90, respectively (P<.0001). Anterior chamber depth measurements did not differ clinically (0.056 mm) nor did sulcus-to-sulcus determinations (0.039 mm).
Biometry, patient comfort, and ease of use were better with the ClearScan bag/balloon technology than with the traditional open-shell technique.
Available from: Jose De la Cruz
- " However, this technique is considered a contact technique because it requires immersion (water bath) or contact of the eye with a plastic balloon and needs a highly trained examiner.  Furthermore, imaging of the implanted KPro by UBM is limited because the prosthesis material causes artifacts impairing the visualization of anterior segment anatomical details. In comparison, AS-OCT allows noninvasive, noncontact, high-resolution cross-sectional imaging of the anterior segment. "
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ABSTRACT: To quantitatively evaluate the anterior segment using anterior segment optical coherence tomography (AS-OCT) following Boston keratoprosthesis type 1.
A retrospective study consisted of AS-OCT imaging at a single time point postoperatively in 52 eyes. Main outcomes measures include anatomical and functional anterior chamber depth (ACD), angle (ACA) and peripheral and proximal synechiae.
The mean time point of imaging was 19.3 months postoperatively. Average anatomical and functional ACD was 2.0 and 0.21 mm respectively, and mean ACA ranged from 2.5° to 6.14° in representative meridians. An average of 8.7 clock hours of angle closure was observed in the 25 eyes in which all meridians were imaged. The majority of eyes showed peripheral (86.5%) and proximal (67.3%) synechiae.
AS-OCT is a useful tool for quantitative evaluation of anterior segment and angle after keratoprosthesis, which is otherwise poorly visible. The majority of eyes showed shallow ACD, extensive angle closure and synechiae formation.
Available from: Alice Chuang
- "The superior and inferior anterior chamber angles were imaged at the limbus using the VuMax II UBM (Sonomed, Lake Success, NY) in high resolution mode with a 35 MHz probe tipped with a ClearScan Cover under topical anesthesia as previously described . Of note, the technique was modified by filling the bag to the lower aspect of the sealing collar instead of to the top end. "
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ABSTRACT: Purpose. To investigate age- and position-related changes of anterior chamber angle anatomy in normal, healthy eyes. Patients and Methods. Thirty subjects were separated into a younger and older cohort. The superior and inferior anterior chamber angles of the eyes were measured in supine and sitting positions by ultrasound biomicroscopy (UBM) with bag/balloon technology. Statistical analysis was used to evaluate positional and age-related changes in angle morphology. Results. In the younger cohort, no location or positional differences in angle anatomy were observed. In the older cohort, the inferior quadrant was significantly narrower than the superior quadrant (P = 0.0186) in the supine position. This cohort also demonstrated an interaction effect between position and location. In the older cohort, the angle was deeper inferiorly while the subject was sitting but was deeper superiorly while the subject was supine.
Conclusion. Comparison of positional variations in anterior chamber angle anatomy as measured by UBM has recently become possible. This study found that age-related positional changes in the anterior chamber angle anatomy exist in normal healthy eyes.
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