Ultrasound biomicroscopy as a diagnostic tool in infants with primary congenital glaucoma

Purpose: Studying the role of ultrasound biomicroscopy (UBM) in detection of anterior segment changes in infants with primary congenital glaucoma (PCG). Methods: Cross-sectional study that included 25 eyes of 15 patients suffering from PCG and a control group of 15 eyes of ten age-and sex-matched participants. Diagnosis of PCG was based on clinical data (intraocular pressure, corneal diameter, fundus examination and amplitude-modulation scan measurement of axial length). UBM examination was done for all participants for measurement of central corneal thickness, anterior chamber depth, lens thickness, iris thickness (measured 2 mm from the iris root and again at the thickest point near the pupil), zonular length, posterior chamber depth, and angle of anterior chamber. Qualitative evaluation was done for abnormal angle membranes, iris insertion level, and ciliary processes position and configuration. Results: Mean age +/- standard deviation was 10.32 +/- 3.59 months in the study group and 14.54 +/- 5.9 months in the control group. The central corneal thickness, anterior chamber depth, zonular length, and angle of anterior chamber were significantly larger in the study group than in the control group, with mean values 700 +/- 190 mu m, 3.55 +/- 0.32 mm, 1.02 +/- 0.15 mm, and 58.47 degrees +/- 5.57 degrees, respectively. The posterior chamber depth had a mean of 0.33 +/- 0.06 mm, which was significantly smaller than that of the control group. In the study group, the mean iris thickness 2 mm from the iris root was 0.32 +/- 0.04 mm, the mean iris thickness at the thickest point near the pupil was 0.38 +/- 0.08 mm, and the mean lens thickness was 3.32 +/- 0.18 mm. These three parameters were smaller than the control group but the difference was insignificant. Loss of normal iris configuration was detected in all eyes of the study group. Anterior iris insertion was detected in 56% of the eyes in the study group, and abnormal angle membrane was found in 12%. Conclusion: UBM is a useful tool for detection of anterior segment changes in PCG, which is helpful especially in cases with opaque cornea or cases with borderline clinical findings.