Ultrasound Biomicroscopy Detects Peters' Anomaly and Rieger's Anomaly in Infants

Classifications of anterior segment structure of congenital corneal opacity in infants and toddlers by ultrasound biomicroscopy and slit-lamp microscopic photographs: an observational study

BACKGROUND

The structural features have an impact on the surgical prognosis for congenital corneal opacity (CCO). The structural classification system of CCO, however, is lacking. Based on data from ultrasound biomicroscopy (UBM) findings in infants and toddlers with CCO, this research proposed a classification system for the anterior segment structure severity.

METHODS

Medical records, preoperative UBM images and slit-lamp photographs of infants and toddlers diagnosed with CCO at University Third Hospital between December 2018 and June 2022 were reviewed. According to the anterior segment structural features observed in UBM images, eyes were classified as follows: U1, opaque cornea only; U2, central anterior synechia; U3, peripheral anterior synechia combined with angle closure; and U4, aniridia or lens anomaly. The opacity appearance and corneal vascularization density observed in slit-lamp photographs were assigned grades according to previous studies. The extent of vascularization was also recorded. The corresponding intraocular anomaly classifications and ocular surface lesion severity were analysed.

RESULTS

Among 81 eyes (65 patients), 41 (50.6%) were right eyes, and 40 (49.4%) were left eyes. The median age at examination was 6.91 months (n = 81, 1.00, 34.00). Two (2.5%) of the 81 eyes were classified as U1, 20 (24.7%) as U2, 22 (27.2%) as U3a, 11 (13.6%) as U3b and 26 (32.1%) as U4. Bilateral CCO eyes had more severe UBM classifications (P = 0.019), more severe dysgenesis (P = 0.012) and a larger angle closure (P = 0.009). Eyes with more severe UBM classifications had higher opacity grades (P = 0.003) and vascularization grades (P = 0.014) and a larger vascularization extent (P = 0.001). Eyes with dysgenesis had higher haze grades (P = 0.012) and more severe vascularization (P = 0.003 for density; P = 0.008 for extent), while the angle closure range was related to haze grade (P = 0.013) and vascularization extent (P = 0.003).

CONCLUSIONS

This classification method based on UBM and slit-lamp photography findings in the eyes of CCO infants and toddlers can truly reflect the degree of abnormality of the ocular surface and anterior segment and is correlated with the severity of ocular surface anomalies. This method might provide meaningful guidance for surgical procedure design and prognostic determinations for keratoplasty in CCO eyes.

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

Background

Axenfeld-Rieger syndrome (ARS), a developmental disorder, involves anterior segment abnormalities and can lead to glaucoma. However, limited research has addressed the ultrasound biomicroscopy (UBM) characteristics of ARS. This study aimed to assess the anterior chamber angle features using UBM in ARS and determine their correlation with glaucoma severity and mutant genes.

Methods

UBM examination was conducted for 42 patients diagnosed with ARS and glaucoma. The morphology of the anterior chamber angle was classified into 6 types (type A, pure high iris insertion; type B, posterior embryotoxon; type C, iris process; type D, trabecular-iris synechia; type E, peripheral iridocorneal adhesion; type F, goniodysgenesis). Candidate genes were sequenced with next-generation sequencing. Correlations of clinical characteristics with angle dysgenesis types and mutant genes were analyzed.

Results

Among the 42 patients recruited, 6 eyes were excluded for poor quality UBM images or lack of glaucoma development. The remaining 78 eyes were categorized into 6 groups according to their dominant type of anterior chamber angle (>2 quadrants). There were statistically significant differences in onset age of glaucoma (P<0.001), untreated intraocular pressure (IOP) (P=0.016), vertical cup to disc ratio (P=0.001), and age at surgery (P<0.001) among the groups. Eyes in the type C and D groups developed glaucoma and underwent surgery at an earlier age, while eyes in the type B, E, and F groups developed glaucoma at a relatively later age. Eyes in type A group developed glaucoma and underwent surgery at the latest age, and had the lowest untreated IOP compared to the other groups. Patients with FOXC1 defects were more likely to have angle type B, type C, and type D (accounting for 93.8% of the total), whereas patients with PITX2 defects were more likely to have angle type A, type E, and type F (accounting for 92.1% of the total).

Conclusions

UBM is powerful for evaluating the anterior segment abnormalities in ARS. Combined with genetic testing results, the morphological classification helps to assess the severity of glaucoma.

A Novel Technique for Anterior Segment Imaging Using B-scan Ultrasonography When Ultrasound Biomicroscopy Is Unavailable

Ultrasound biomicroscopy offers high-resolution images of anterior segment anatomy, essential for determining surgical intervention in special circumstances, yet is sometimes unavailable. The authors describe a novel technique to obtain gross anterior segment visualization using a commonly available instrument, B-scan ultrasonography, and compare it to ultrasound biomicroscopy imaging from two pediatric cases. [J Pediatr Ophthalmol Strabismus. 2022;59(5):e58-e61.].

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

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

An online search was performed on PubMed in December 2020. After a critical appraisal of the included articles, study and patient characteristics were summarized. The UBM measurements of the anterior segment in PCG of the different studies 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.

A systematic review of ultrasound biomicroscopy use in pediatric ophthalmology

Ultrasound biomicroscopy (UBM) is the only available option for noninvasive, high-resolution imaging of the intricate iridociliary complex, and for anterior segment imaging with corneal haze or opacity. While these unique features render UBM essential for specific types of trauma, congenital anomalies, and anterior segment tumors, UBM imaging has found clinical utility in a broad spectrum of diseases for structural assessments not limited to the anterior intraocular anatomy, but also for eyelid and orbit anatomy. This imaging tool has a very specific niche in the pediatric population where anterior segment disease can be accompanied by corneal opacity or clouding, and anomalies posterior to the iris may be present. Pediatric patients present additional diagnostic challenges. They are often unable to offer detailed histories or fully cooperate with examination, thus amplifying the need for high-resolution imaging. This purpose of this systematic review is to identify and synthesize the body of literature involving use of UBM to describe, evaluate, diagnose, or optimize treatment of pediatric ocular disease. The collated peer-reviewed research details the utility of this imaging modality, clarifies the structures and diseases most relevant for this tool, and describes quantitative and qualitative features of UBM imaging among pediatric subjects. This summary will include information about the specific applications available to enhance clinical care for pediatric eye disease.