Transitioning to microincision cataract surgery

OSN Supersite

When using smaller incisions, the primary fluidic consideration is the decrease in flow due to the narrowness of the phaco needle and sleeve. Poiseuille’s equation states that the flow of fluid through tubing is proportional to the radius of the tubing to the power of 4. This means that a small change in the tubing radius provides a much larger change in the amount of fluid flow. Remember the analogy of the drinking straw: With a narrow cocktail straw, you would need a large amount of vacuum in your mouth to draw a small amount of fluid. But with a larger drinking straw, just a small amount of vacuum in your mouth produces a good deal of fluid flow. When first trying sub-2-mm MICS, change the vacuum setting to a higher level, at least 50% above or even double your standard level with sub-3-mm surgery. In order to keep the maximum level of fluidic inflow and inflow pressure, which aids in preventing surge, keep the bottle at the highest level because you can always bring it down should you find the anterior chamber to be over-pressurized. Should you further wish to balance the fluidics, an outflow restrictive tubing can be used. A benefit of MICS is the small amount of fluid that is passed through the eye, with routine cases requiring just a fraction of the fluid of larger bore surgery.With improved phaco platforms and high-quality single-piece acrylic IOLs, the transition to MICS is relatively easy, with a minimal learning curve for the surgeon and improved results for the patients.