Forty-eight eyes with massive periretinal proliferation were examined with ultrasonography. In addition to the triangular retinal detachment T-sign was indicative of severe MPP. And irregular thickening and bending of the retina were observed on ultrasonography in eyes with MPP. The detached retina was immobile in all eyes. Preoperative ultrasonographic findings did not prove the value on the assessment of operative prognosis. REFERENCES Bronson, N.R. & Turner, F.T. A simple B-scan uitrasonoscope. Arch. Ophthalmol. 90: 237 (1973). Coleman, D.J., Koning, W.F. & Katz L.: A Hand-Operated...