[A method of measuring iris radius by computerized image analysis].

A new method of measuring the iris contour has been set up with a personal computer. The model of a parabolic curve, an approximate mimic iris contour curve, was traced to define the profile contour of the iris from a photograph. A radius measured from the apex of the curvature of the parabola, named iris radius (IR), was calculated by a computer to describe the degree of the curvature of the iris contour. The iris radius of 93 eyes of 68 cases with early pupillary block primary angle closure glaucoma were measured by this method. The results show that the mean iris radius of cases with glaucoma is shorter than that of the normal age matched controls (53 cases 106 eyes) and there is statistical significant difference (P < 0.01). This method of measurement can be an effective method to further study the early diagnosis and pathogenic mechanism of the pupillary block angle closure glaucoma.