Objective To lay a foundation for study of optic narve damage in glaucoma by measuring the number and diameter of the optic nerve fibers and optic disc area in normal individuals. Methods The cross-sections of the optic nerve and the optic discs in 15 normal human eyes were examined with the use of a computerized image analysis system. Results The mean nerve fiber count was 10.08times;105plusmn;1.61times;105. The mean nerve fiber diameter was (0.99plusmn;0.04)mu;m. The nerve fiber count increased significantly with the increasing of cross-section area of the optic nerve, but the nerve fiber count was independent of the optic dise area. Conclusion This study provided anatomic basis for predicting the prognosis of optic nerve damage and further studyv of nerve damage in glaucoma. (Chin J Ocul Fundus Dis,1999,15:16-19)