A collection of blood in the lower portion (due to gravity) of the anterior chamber of the eye, usually following trauma.
Glaucomas can result as a complication of a hyphema.
Grading of hyphemas goes as follows:
Microscopic hyphemas are those in which blood is only visible as cells floating within the anterior chamber. In this case there is not enough blood to cause visible layering.
Grade 1: Blood occupies less than one-third of the anterior chamber volume.
Grade 2: Blood fills one-third to less than one-half of the anterior chamber.
Grade 3: Blood fills greater than one-half of the chamber, but does not completely fill the chamber.
Grade 4: Total hyphema
Total, clotted hyphemas are dark brown or black and are referred to as "8-ball" hemorrhages.