Diagnosis immersion B Scan ultrasonography is very useful to study anterior segment lesions of the eye (angle of iris, anterior synechiae, iris and ciliary body tumors). We studied forty patients with posterior segment lesions of the eye with this technique. We think that it is useful to study anterior vitreous (cyclitic membranes, vitreoretinal relationships in front of ora serrata). It is useful to study the posterior segment of the eye with this immersion technique, in case of high hyperopia, microphthalmos, phtysis bulbi with retinal detachment and to evaluate acute vitreous hemorrhages, vitreous membranes in case of proliferation diabetic retinopathy, tractional retinal detachment and vitreoretinal adhesions. All the structures were better defined with the immersion technique than with the contact technique: with the immersion technique, these anterior structures are located close to the focus point of the probe (which is the case with the contact technique).