Purpose To verify the effectiveness of combined B-scan ultrasonoscopy and ultrasound biomicroscopy(UBM)imagings in diagnosis of retinal detachments. Methods To contrast the manifestations in vitrectomy operations with the findings of preoperative combined B-scan ultrasonic and UBM examinations in 25 eyes of 25 cases in which 18 eyes with rhegmatogenous retinal detachment and 7 eyes with traumatic retinal detachment were included. Results B-scan ultrasonic imagings were divided into four types: type C,type V,type upsilon; and type gamma;,which included 6 eyes,2 eyes,4 eyes and 11 eyes respectively,and from type C to type gamma;,the retinal detachments manifested themselves from simple posterior segment proliferative vitreoretinopathy(PVR)to both anterior and posterior PVR.The imagings of UBM were divided into 3 types:shallow retinal detachment,retinal circumferential contraction and retinal anterior displacement,which reflected the degree of anterior PVR from lightness to severeness. Conclusions The technique of combined B-scan ultrasonoscopy and UBM can be used to access the severity of the retinal detachments,hence would be beneficial in diagnosing anterior and posterior PVR,designing the surgical precedures and assessing the prognosis. (Chin J Ocul Fundus Dis,1998,14:16-20)