The disc and the field in glaucoma.

The previous descriptions of the optic nerve head were reviewed. A study was done using discriminant analysis, in which an 85% separation was obtained by means of the discriminant function in a prospective study. The false positives showed a higher incidence of subsequent visual field defects from the true negatives. The pitfalls of the use of the optic nerve head appearance in the recognition of glaucomatous visual field defects were discussed.