<prompt> Microcornea is defined as:10 mm corneal diameter at bih13 mm corneal diameter at bih10 mm axial length at bih20 mm axial length at bih  <response>: Microcornea 10 mm corneal diameter at bih. Megalocornea 13 mm after 2 yr of age or 11.7 mm before 2 yr of age. 