Although corrected loss variance (CLV) may enhance the sensitivity of field examinations in the early stages of glaucoma, the value of CLV has not been investigated with advancing glaucoma. In this study we report mean defect (MD) and CLV for 266 Octopus field examinations (a total of 57 eyes and 47 patients with open-angle glaucoma) collected over a period of approximately 6 years on a stored database system. We find that CLV is generally elevated (relative to the normal controls) independent of MD. However, the elevated level of CLV does not vary with increasing field loss as indicated by MD. A classification system for defining stages of glaucoma is proposed utilizing CLV and MD as a combined index.