Comparative study of vitreoretinal relationships using biomicroscopy and ultrasound

We prospectively studied 29 consecutive eyes with proliferative diabetic retinopathy that showed media clear enough to enable characterization of vitreoretinal relationships by biomicroscopy. Vitreoretinal relationships were also determined by contact B-scan ultrasound. With both techniques, these relationships were documented by photographs and drawings. Biomicroscopy showed complete posterior vitreous detachment (PVD) in 4 eyes (14%), partial PVD in 18 (62%), and no PVD in 7 (24%). Ultrasound examination revealed complete PVD in 4 eyes (14%), partial PVD in 19 (66%), and no PVD in 6 (21%). The results we obtained using ultrasound agreed significantly with those obtained by biomicroscopy [Cohen's kappa = 0.93, 95% confidence interval = (0.80, 1.06)]. Ultrasound detected vitreous changes more easily than biomicroscopy when mild media opacities were present and when the equatorial areas of the globe were examined. Results suggest that ultrasound is adequate to determine vitreoretinal relationships in eyes with clear media and that it is a good alternative to biomicroscopy in eyes with significant media opacities.