Outcomes of High vs Physiological Intraocular Pressure During Cataract Surgery Using ACTIVE SENTRY

Plain-language summary

Cataract surgery is a widely performed procedure across the world that helps restore vision in many patients suffering from cataracts. Irrigation is an essential component of the surgery. Fluid is constantly circulated to help regulate temperature as heat is generated with ultrasound energy, to minimize tissue trauma, and to create an intraocular pressure (IOP) sufficient to keep the anterior chamber (AC) stable. In parallel, aspiration brings the components of the cataract closer to the surgical instrument. A balance between irrigation and aspiration during surgery is essential to maintain stability in the AC. However, an ideal flow rate, which influences IOP during surgery, is yet to be determined. Most recent studies with Centurion Active Sentry show that there is similar efficiency between higher and lower IOP settings. Traditionally, high-flow rates have been used in advanced cataracts and are believed to make space in the AC. However, they are known to create fluid turbulence and are associated with risks of tissue damage, including cell loss in one of the cornea's layers. High IOP during surgery has also been shown to cause damage to the optic nerve as well as to the retina. Distorting and stretching the AC during phacoemulsification have also been associated with increased pain experienced by the patient. Comfort can be achieved by lowering pressure levels. Low-flow rates have a better safety profile, reduce IOP and pressure fluctuations while offering equal efficiency, including comparable surgical time. Using central corneal thickness (CCT) as an indicator of corneal trauma, it has been shown that patients that have had surgery with low-flow rates present no change in the CCT postoperatively as opposed to patients in the high-flow rates. As less fluid turbulence is created with low-flow rates, there is decreased risk of fragment contact with the cornea's inner surface, thus reducing cell loss. Alcon Laboratories, Inc. developed Active Fluidics which allows to stabilize intraocular pressure and prevent IOP fluctuations as well as IOP surges during surgery. It is now further equipped with the Active Sentry handpiece which is integrated to the surgical instrument and acts as a sensor to pressure variation. It allows rapid feedback to maintain a stable AC. Our research project aims to assess the outcomes following phacoemulsification done with physiological IOP with the help of the Active Sentry handpiece compared to traditional high IOP levels.

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