Real-time intraocular pressure measurement in standard and microcoaxial phacoemulsification

PURPOSE: To evaluate intraocular pressure (IOP) in the vitreous cavity during various stages of cataract surgery. SETTING: University Eye Hospital, Ludwig-Maximilians University, Munich, Germany. METHODS: In consecutive eyes having combined phacoemulsification, intraocular lens implantation, and pars plana vitrectomy, IOP was monitored in real time through a 25-gauge pars plana cannula connected to an external pressure transducer. Surgery was performed by standard clear corneal phacoemulsification with a 2.5 mm incision and a Mega-Tip (1.26 mm aperture) (Group 1) or by microcoaxial phacoemulsification with a CMP-Tip (0.80 mm aperture) (Group 2). RESULTS: The 2 groups had 5 eyes each. The mean IOP in Group 1 and in Group 2, respectively, was 15.9 mm Hg +/- 9.5 (SD) and 17.0 +/- 13.5 mm Hg preoperatively (P = .442), 40.1 +/- 12.7 mm Hg and 36.5 +/- 17.2 mm Hg during lens removal (P<.001), 17.6 +/- 14.2 mm Hg and 22.6 +/- 8.6 mm Hg during irrigation/aspiration (P<.001), 13.3 +/- 13.2 mm Hg and 16.3 +/- 13.1 mm Hg during IOL implantation (P = .005), and 22.9 +/- 7.0 mm Hg and 21.5 +/- 10.0 mm Hg after IOL implantation through the end of surgery (P = .329). CONCLUSIONS: Although the IOP levels were significantly lower than those in previous studies, both phacoemulsification techniques had safe IOP profiles during various steps of surgery. Real-time IOP monitoring may prevent the surgeon from inducing excessive IOP elevation during intraocular manipulation.