Objective To evaluate the applic ation of blue-on-yellow(B/Y) perimetry in detecting the early visual field loss of glaucoma． Methods The B/Y perimetry of the G2 strategy in the OCTOPUS 101 perimetry was used to examine the visual field of 16 normal persons (32 eyes), 25 cases (35 eyes) of primary open-angle glau coma (POAG) with abnormal white-on-white (W/W) visual fields, 15 cases (15 eye s) of early POAG with normal W/W visual field, and 11 cases (22 eyes) of suspect ed POAG． Results The mean sensitivity (MS) in the normal cases, suspected POAG, early POAG, middle POAG, and late POAG was ( 23．24plusmn;1．22) dB，(20．97plusmn;3．42) dB，(18．44plusmn;3．57) dB，(11．04plusmn;1．85) dB and (8．55plusmn;2．29) dB, respectively． It was demonstrated that B/Y perimetry was more sensitive than W/W perimetry in detecting the glaucomatous visual fi eld defects,and its sensitivity was 92% and specificity was 90．62%． The averag e number of defective points in central visual field with B/Y perimetry was more than that with W/W perimetry in early and middle POAG． Conclusion B/Y perimetry is a relatively sensitive method for detection of the early visual field loss in POAG． (Chin J Ocul Fundus Dis, 2001,17:125-127)