Comparison of the anterior chamber angle structure between children and adults

To investigate the anterior chamber structure in children and adults with a similar axial length (AL).

A total of 50 children (mean age, 7.1 ± 3.3 years; range, 3-16) with mainly refractive error and 50 adults (mean age, 73.7 ± 7.8 years; range, 50-85) with short AL were included. The mean AL was 22.21 ± 0.88 mm (range, 20.67-23.97 mm) in children; 22.34 ± 0.53 mm (range, 20.50-22.96 mm), in adults. The corneal curvature, spherical equivalent, AL, central corneal thickness (CCT), inter-scleral spur distance, perpendicular distance, anterior chamber depth (ACD), angle opening distance (AOD), and lens vault were measured. An independent t test and a stepwise regression analysis were used to analyze the data.

There were no significant differences between groups in AL, spherical equivalent, and perpendicular distance. By comparison, the children had larger corneal curvature (children:adults = 7.70:7.40 mm), longer inter-scleral spur distance (11.65:11.20 mm), greater CCT (560:522 μm), deeper anterior chamber (3.05:2.53 mm), and larger AOD (0.56:0.37 mm) than adults (all P < 0.01). The lens vault was smaller in the children than in the adults (0.04:0.54, P < 0.01). The predictive factors for lens vault were the ACD (coefficient = -0.407), inter-scleral spur distance (0.307), AOD (-0.650), group (children, -0.108) and corneal curvature (-0.214). The predictive factors for the AOD were the lens vault (-0.310), inter-scleral spur distance (0.140), and corneal curvature (-0.143).

In our cohort, the anterior chamber angle (the semicircle structure of the anterior segment) in children was larger than in adults. This may partially explain why, despite having a short AL, children rarely develop primary angle closure.