Ultrasound biomicroscopy of the anterior segment in patients with primary congenital glaucoma: a review of the literature

Abstract

Purpose.Primary congenital glaucoma (PCG) is a form of childhood glaucoma caused by maldevelopment of the anterior chamber. Disease severity differs greatly amongst patients. Ultrasound biomicroscopy (UBM) is a non-invasive technique that can visualize the anterior segment in infants in vivo. The purpose of this narrative review is to make an overview of the UBM data in PCG and study the applicability of UBM in characterizing the disease. Methods. AnonlinesearchwasperformedonPubMedinDecember2020.Afteracriticalappraisal of the included articles, study and patient characteristics were summarized. The UBM measurements ofthe anteriorsegment in PCG ofthe differentstudies were analysed. Results.Six studies were included in this review. All were cross-sectional prospective studies. A total of 221 PCG eyes were examined. PCG eyes showed a larger trabecular iris angle, decreased iris thickness, narrower or absent Schlemm's canal and an increased zonular length compared to controls. Abnormal tissue membrane covering the trabecular meshwork and abnormal insertion of the iris and ciliary process were frequently found. The success rate of glaucoma surgery depended on the severity of anterior segment malformations found with UBM. Conclusion.Malformations of the anterior segment in PCG can be demonstrated by UBM in vivo. This imaging can help to characterize disease severity and might support surgical treatment decisions.

Comparison between B scan ultrasonography, immersion UBM and contact UBM techniques in evaluation of the lens area

“…Contact UBM delivers images with resolutions near to immersion UBM with advantage of sterility for patients with recent operations [4] . This study agreed with Abdolrazaghnejad A et al, [5] who found that B Scan ultrasonography is relatively contraindicated in the presence of rupture globe to avoid further trauma and contamination of the wound, so primary closure should be performed previous to ultrasound examination [2] . If ultrasound examination has to be performed prior to primary closure, it should be performed with caution to prevent possible trauma to the eye.…”

“…Ultrasound Biomicroscopy (UBM) is a technique used for imaging of the ocular anterior segment. It was first introduced by Pavlin and Foster in the early 1990's to obtain crosssections of the ocular tissues at microscopic resolution [2] . Compared to regular ultrasound modalities such as B scan which uses a frequency (10 MHz), UBM uses a much higher frequency transducer (35-100 MHz) [5] .…”

The morphology of angle dysgenesis assessed by ultrasound biomicroscopy and its relationship with glaucoma severity and mutant genes in Axenfeld-Rieger syndrome

“…The type A angle morphology of ARS in our study shared similarities with the ultrasound biomicroscopic features reported in primary congenital glaucoma (PCG), which also arises from the hindered posterior sliding of uveal tissue. These shared features include a thin iris, small ciliary body, abnormal tissue membrane, anterior iris insertion, and absence of Schlemm’s canal ( 30 , 31 ), thus constituting evidence supporting the phenotypic overlap between ARS and PCG.…”

Characteristics of the Ciliary Body in Healthy Chinese Subjects Evaluated by Radial and Transverse Imaging of Ultrasound Biometric Microscopy

“…UBM can be used to measure any quadrant on living subjects, as it is unaffected by shrinkage. Since its inception, UBM has been used in many clinical and preclinical studies associated with CB-related disease, and it is irreplaceable for the study of the posterior chamber and the innermost structures of the iridociliary region compared to AS-OCT [4,[18][19][20]. To the best of our knowledge, this is the first report that demonstrated the morphology parameters of the CB from both radial and transverse scans in four different quadrants in vivo of Chinese people and the correlations between them with systemic and ocular parameters.…”