Abstract: Glaucoma is a kind of retinal diseases with the feature of optic nerve atrophy and visual field defect, which is the second foremost reason of blindness. Early glaucoma is not obvious, so the screening and diagnosis of early glaucoma will prevent further development of glaucoma. In this paper, we propose a method to evaluate the pathogenesis of glaucoma that can be divided into three parts:the first is using random forest to segment the retinal nerve fiber layer; the second is using patch searching to segment disk and cup; and the third is calculating the relationship of retinal nerve fiber layer(RNFL) thickness and cup-to-disk ratio(CDR). Experimental results demonstrate that the correlations of the thickness of RNFL with vertical CDR, cup area and rim disk ratio are 0.64, 0.62, 0.54, respectively, which conforms that RNFL thickness and CDR are highly relative and complementary for the glaucoma diagnose. It plays an important role in the study on the development of glaucoma.