Comparison of erbium : yttrium-aluminum-garnet-laser vitrectomy and mechanical vitrectomy - A clinical study

Objective: To evaluate the clinical usefulness of the erbium:YAG (yttrium-a luminum-gamet) laser for vitrectomy and to compare it with a conventional m echanical vitrectomy system regarding the intraoperative parameters. Design: Prospective, randomized, clinical trial. Participants: Thirty eyes of 30 patients underwent vitrectomy, 15 eyes in e ach group. Methods: For mechanical vitrectomy, a commercially available vitrectomy uni t was used. The operating parameters, cutting rate (7 Hz = 420 cpm), maxima l suction force (300 mmHg), and aspiration flow (20 ml/min), were held cons tant. A newly developed erbium (EV):YAG laser unit and handpiece was used f or laser vitrectomy with predetermined parameters for cutting rate (70 Hz = 4200 cpm), maximal suction force (50 mmHg), and aspiration flow (20 ml/min ). Surgery parameters were recorded in real time and the operation was vide o recorded. The clinical follow-up time was a minimum of 3 months (average, 6.2 months; range, 3-9 months). Main Outcome Measurements: The surgery time was comparable in both groups. During Er:YAG laser vitrectomy, the average suction force was significantly reduced (P < 0.001) compared with that during mechanical vitrectomy. The m ean-square variation in suction as a measure to quantify the forces acting on intraocular structures during surgery was significantly smaller in the E r:YAG laser vitrectomy group (P << 0.001). Conclusions: Erbium:YAG laser vitrectomy may provide a semicontinuous proce dure. This technique minimizes periodical intraoperative forces and movemen ts of intraocular structures and may provide, therefore, a safer vitrectomy . (C) 2000 by the American Academy of Ophthalmology.