AIM:To evaluate the pattern electroretinogram (PERG) and blue-on-yellow perimetry (B/Y P) in the early diagnosis of primary open angle glaucoma (POAG).METHODS:Twenty-five patients 42 eyes with suspected open angle glaucoma (SOAG) confirmed by standard automated perimetry were compared with 25 normal men 50 eyes in P50,N95 amplitude,peak time of PERG and the vision of B/Y P.RESULTS:In the patients with SOAG,amplitude of P50,N95 decreased and peak time extended in 19 patients 34 eyes by PERG examination,vision abnormalities were found in 14 patients 24 eyes by B/Y P examination.There were significant differences between the patients with SOAG and normal men in the examination of PERG and B/Y P (P<0.01).CONCLUSION:The retinal ganglion cells have been damaged in the patients with SOAG,combination of PERG with B/Y P is an effective method in the early diagnosis of POAG.