Collagen I Defect Corneal Profiles in Osteogenesis Imperfecta.

PURPOSE: The goal of this study was to evaluate corneal profiles of patients with osteogenesis imperfecta (OI) due to a collagen I gene mutation.

METHODS: This was a cross-sectional comparative study. There were 84 eyes from 42 patients with OI types I, III, and IV who were recruited from the OI Clinic at the Clinical Hospital of Porto Alegre, Brazil. All cases presented either COL1A1 or A2 gene mutations. Controls were matched by sex, age, and refractive error. Corneal Scheimpflug tomography was used to determine curvature and thickness parameters in both groups.

RESULTS: Quantitative collagen mutations were found only in OI type I. Qualitative mutations were responsible for all mutations observed in type III and IV patients. Each OI type presented significantly lower pachymetric values at the thinnest point compared with controls (443.7-505.1 vs. 541.9-548.5 μm; P < 0.001). In addition, significantly lower pachymetric values were observed in patients with OI compared with controls in all positions between the central and corneal periphery (581.4-657.0 vs. 704.5-720.7 μm at an 8.0-mm-diameter circle; P < 0.001). Differences in anterior and posterior radii of curvatures, respectively, between patients with OI and controls were not statistically significant (7.64-7.80 vs. 7.65-7.69 mm; P > 0.05) except for a lower anterior radii of curvatures in type III (7.33 vs. 7.72 mm; P < 0.01).

CONCLUSIONS: Although patients with OI have homogenously thinner corneas compared with controls, we observed that a collagen I chain mutation was not responsible for corneal curvature alterations in OI.