Intraocular pressure during phacoemulsification.

PURPOSE To assess changes in intraocular pressure (IOP) during standard coaxial or bimanual microincision phacoemulsification. SETTING Oregon Eye Center, Eugene, Oregon, USA. METHODS Bimanual microincision phacoemulsification (microphaco) was performed in 3 cadaver eyes, and standard coaxial phacoemulsification was performed in 1 cadaver eye. A pressure transducer placed in the vitreous cavity recorded IOP at 100 readings per second. The phacoemulsification procedure was broken down into 8 stages, and mean IOP was calculated across each stage. Intraocular pressure was measured during bimanual microphaco through 2 different incision sizes and with and without the Cruise Control (Staar Surgical) connected to the aspiration line. RESULTS Intraocular pressure exceeded 60 mm Hg (retinal perfusion pressure) during both standard coaxial and bimanual microphaco procedures. The highest IOP occurred during hydrodissection, ophthalmic viscosurgical device injection, and intraocular lens insertion. For the 8 stages of the phacoemulsification procedure delineated in this study, IOP was lower for at least 1 of the bimanual microphaco eyes compared with the standard coaxial phaco eye in 4 of the stages (hydro steps, nuclear disassembly, irritation/aspiration, anterior chamber reformation). CONCLUSION There was no consistent difference in IOP between the bimanual microphaco eyes and the eye that had standard coaxial phacoemulsification. Bimanual microincision phacoemulsification appears to be as safe as standard small incision phacoemulsification with regard to IOP.