Large black eye, seen in large corneas, is a congenital developmental abnormality with larger than normal corneal diameter and no abnormalities in IOP, fundus and visual function examinations, and is usually considered to be a genetic disorder. The majority of cases are male, occur bilaterally and develop symmetrically. The horizontal diameter of the cornea is generally greater than 13 mm, the vertical diameter is greater than 12 mm, and the anterior segment of the eye is disproportionately enlarged. Large corneas generally present with a clear cornea and well-defined corneal border. A small number of patients may have a combination of other ocular abnormalities, such as iris, ciliary body, pupil and lens abnormalities. The diagnosis of large corneas should be differentiated from congenital glaucoma, which usually presents with large, cloudy corneas, dilated and poorly defined corneal margins, and elevated intraocular pressure.