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AIM: To measure the optimal anterior chamber pressure (ACP) for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye. METHODS: The 20-gauge and 21-gauge straight tips with yellow and orange sleeves, respectively, were covered by a test chamber combined with a pressure sensor for measuring ACP. This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip, and 300 and 250 mm Hg with a 21-gauge tip. Using a porcine eye, a pressure sensor fixed with a 0.9 mm corneal incision measured ACP. For the posterior capsule contact assay, porcine eyes were treated as described above, and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip, and 300 and 250 mm Hg for the 21-gauge tip. The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded, and the estimated ACP was calculated. RESULTS: The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips. Similarly, proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal. The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm (20.2±7.9 mm Hg) at 200 mm Hg with a 20-gauge tip, 35.0±10.0 cm (16.6±6.3 mm Hg) at 150 mm Hg with a 20-gauge tip, 47.5±12.6 cm (18.7±8.7 mm Hg) at 300 mm Hg with a 21-gauge tip, and 32.5±5.0 cm (15.7±3.5 mm Hg) at 250 mm Hg with a 21-gauge tip. CONCLUSION: A comprehensive understanding of this chamber system's characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.

Purpose: To compare anterior chamber stability and surgical efficiency in one-handed phacoemulsification, comparing Ozil and Active Sentry (AS) handpieces. Methods: Observational and comparative study. Selected patients were divided into two groups, AS and Ozil handpieces, and underwent one-handed phacoemulsification. Parameters like IOP per quadrant, vacuum, and aspiration flow were fixed in all surgeries. The study endpoints were intraoperative anterior chamber instability score (IACIS), cumulative dissipated energy (CDE), followability, and surgery duration. Results: Mean age was 71.42 years in the AS group vs. 73.97 in the Ozil Group. Mean Axial Length was 22.85 ± 1.21 mm with Active Sentry vs. 23.3 ± 1.29 mm with Ozil (p = 0.324). IACIS was 0.10 ± 0.30 with AS vs. 0.63 ± 0.71 with Ozil (˂0.001*). CDE was 9.95 ± 4.76 percent-seconds with AS vs. 10.89 ± 6.55 percent-seconds with Ozil (0.519). The followability score was 0.74 ± 0.855 with AS vs. 0.83 ± 0.874 with Ozil (p = 0.678). Surgery duration was 19.00 ± 5.44 min with AS vs. 24.57 ± 6.51 with Ozil (p < 0.001). Conclusions: The Active Sentry handpiece improves anterior chamber stability in one-handed phacoemulsification while maintaining surgical performance during nucleus removal without an auxiliary side-port. To the best of our knowledge, this is the first study demonstrating that the Active Sentry handpiece can increase anterior chamber stability not only in conventional phacoemulsification but also in one-handed phacoemulsification. [ABSTRACT FROM AUTHOR]

Purpose: To compare anterior chamber stability and surgical efficiency in one-handed phacoemulsification, comparing Ozil and Active Sentry (AS) handpieces. Methods: Observational and comparative study. Selected patients were divided into two groups, AS and Ozil handpieces, and underwent one-handed phacoemulsification. Parameters like IOP per quadrant, vacuum, and aspiration flow were fixed in all surgeries. The study endpoints were intraoperative anterior chamber instability score (IACIS), cumulative dissipated energy (CDE), followability, and surgery duration. Results: Mean age was 71.42 years in the AS group vs. 73.97 in the Ozil Group. Mean Axial Length was 22.85 ± 1.21 mm with Active Sentry vs. 23.3 ± 1.29 mm with Ozil (p = 0.324). IACIS was 0.10 ± 0.30 with AS vs. 0.63 ± 0.71 with Ozil (˂0.001*). CDE was 9.95 ± 4.76 percent-seconds with AS vs. 10.89 ± 6.55 percent-seconds with Ozil (0.519). The followability score was 0.74 ± 0.855 with AS vs. 0.83 ± 0.874 with Ozil (p = 0.678). Surgery duration was 19.00 ± 5.44 min with AS vs. 24.57 ± 6.51 with Ozil (p < 0.001). Conclusions: The Active Sentry handpiece improves anterior chamber stability in one-handed phacoemulsification while maintaining surgical performance during nucleus removal without an auxiliary side-port. To the best of our knowledge, this is the first study demonstrating that the Active Sentry handpiece can increase anterior chamber stability not only in conventional phacoemulsification but also in one-handed phacoemulsification.

Objective To optimize fluid dynamics through measuring intraocular pressure ( IOP) in a venturi phacoemulsification machine in dogs. Procedures In step I, flow and IOP of the test chamber were measured using a pressure transducer with the bottle height ( BH) set at 50, 70, 100, and 120 cm and the vacuum from 30 to 450 mmHg. A 19-gauge phaco and a 0.3-mm irrigation/aspiration (I/A) handpiece were used. In step II, flow and IOP were measured in an enucleated canine eye with a 3.0- and a 3.2-mm clear corneal incision ( CCI), respectively. IOP was measured using the pressure transducer at a 30-mmHg vacuum to allow corneal deformation, to define the fluidic parameters for preventing surge. Results Flow was directly proportional to the BH and vacuum, whereas IOP was directly proportional to the BH and inversely to the vacuum. Flow with an I/A handpiece was significantly less than with a phaco handpiece, explaining why IOP with an I/A handpiece was significantly higher than with a phaco handpiece. With the I/A handpiece, vacuum parameters less than 450 mmHg did not result in corneal deformation. IOP with a 3.2-mm CCI was significantly lower than with a 3.0-mm CCI, with the 3.2-mm flow being greater than the 3.0-mm flow. Conclusions BH during the I/A stage could be reduced to avoid unnecessary stress on the canine eye when using a venturi system. Although phacoemulsification with a 3.2-mm CCI could induce lower IOP, a 3.0-mm CCI might lessen the irrigation flow stress on the eye. [ABSTRACT FROM AUTHOR]