[Ultrasonic diagnosis prior to vitrectomy. Critical evaluation of 51 cases]

In ophthalmology it is of increasing importance to assess intraocular pathology prior to vitroretinal surgery by means of B- and A-mode ultrasound. Even for the experienced examiner with advanced instrumentation, major problems can arise as to whether retinal detachment has developed or not. This task involves the ability for acoustical differentiation of thin tissue membranes. The authors compared preoperative ultrasonic results obtained in 51 cases with the surgical findings during vitrectomy. The presence or absence of retinal detachment was evaluated correctly in 33 cases (91.7%) using high resolution contact B-mode alone. In difficult cases maximal echo amplitudes reflected from the suspected membranes were evaluated using a hand-held A-mode transducer (level difference A-mode echography) in addition to contact B-mode. Even the combined technique, though helpful in most cases, could not detect the presence or absence of retinal detachment in all cases.