Characterization of Angle-Angle Diameter Relationship with Corneal Diameter, Axial Length and Intraocular Pressure in Pediatric Glaucoma

Objective To characterize the relationship of angle-angle diameter (AA) with intraocular pressure (IOP), corneal diameter (CD), and axial length (AL) in pediatric patients with glaucoma. Design Prospective cross-sectional observational study. Participants Nineteen participants (34 eyes) ages 0.12 to 12.5 years (median=1.5 years) with pediatric glaucoma. Methods Ultrasound biomicroscopy (UBM), A-scan biometry, and IOP and CD measurement were performed under general anesthesia prior to intraocular surgery. A masked observer measured AA in each UBM image using ImageJ. Pearson analysis and multivariate regression were performed using R. Main Outcome Measures Correlation and age-adjusted regression relationships between AA and CD, AL, and IOP. Results Twenty-three UBM images from 12 primary congenital glaucoma (PCG) participants, six from three participants with glaucoma following cataract surgery (GFCS), and five from four participants with Sturge-Weber Syndrome-associated glaucoma (SWS) were analyzed. AA showed a strong positive correlation with CD (r = 0.93, p < 0.001) across most age groups and glaucoma subtypes except SWS. AA was also strongly correlated with AL in PCG and GFCS (r = 0.73, p < 0.001; r=0.87, p=0.02), with similar associations seen in participants <1 year old (r = 0.75, p=0.002). CD demonstrated parallel correlations with AL in PCG, GFCS, and infants (r = 0.79, p < 0.001; r=0.88, p=0.02; r=0.78, p < 0.001). No significant correlations were identified between IOP and either AA or CD. In age-adjusted models, AA was not significantly associated with AL or IOP in the overall cohort. However, among PCG eyes, each 1-mm increase in AA corresponded to a significant 1.63-mm increase in AL (p = 0.002). No additional significant associations were observed in other glaucoma subtypes or age groups. Conclusions AA may be clinically useful for diagnosing and monitoring glaucoma in pediatric patients, as it tends to increase proportionally with AL. Further studies in larger populations will improve understanding of how these relationships change with age and disease severity.