Corneal enlargement in congenital glaucoma exhibits predominant peripheral corneal thinning

We aimed to investigate regional corneal thickness changes in patients with congenital glaucoma and enlarged corneas. Medical records of patients with primary congenital glaucoma (PCG) and two control groups of pediatric patients with intermittent exotropia and adult myopic normal tension glaucoma (NTG) patients were reviewed. Anterior segment optical coherence tomography (AS-OCT) was used to measure corneal thickness at seven locations along the 3-9 o'clock meridian: the center, midpoint of the 2-5-mm pericentral zone, corneo-limbal junction, and scleral spur on temporal and nasal sides. Finally, this study included 40 eyes (26 patients) in the PCG group and 78 eyes (42 patients) in the control groups. The PCG group exhibited significantly thinner corneas at the corneo-limbal junction and scleral spur compared to the control groups (all P < 0.001). In particular, thinning was most marked at the corneo-limbal junction (in average, 572.3 ± 76.1 vs. 690.5 ± 38.2 μm). In contrast, the mid-pericentral and central thicknesses were not different between the groups. The angle-to-angle distance was significantly larger in the PCG group compared to the two control groups (13.9 ± 0.8, 12.0 ± 0.2, and 12.0 ± 0.6 mm, all P < 0.001). In conclusion, patients with PCG exhibit predominant peripheral corneal thinning, particularly at the corneo-limbal junction, in addition to the increased corneal diameter. These findings provide in vivo evidence that the corneo-limbal junction and limbus are particularly susceptible to deformation from increased intraocular pressure in the young and elastic eyes.