Creating the 1.8 mm coaxial MICS solution

Key Points

To improve MICS chamber stability, Dr Takayuki Akahosi has recommended increasing the infusion bottle height to 150 cm. A potential concern with this approach is that, when the phaco tip is occluded, the intraocular pressure (IOP) is 110 mmHg. When flow is restored, the pressure will drop proportionate to the outflow rate, but will fluctuate up and down as the tip changes from the occluded to the non-occluded state. The concern, therefore, is not only the maximum pressure that is reached, but also the large pressure swings, both of which may be undesirable in the eye. As an alternative, Dr Amar Agarwal has recommended using pressurized infusion bottles, but the IOP issue remains the same.

Evidence mounts against bimanual MICS

This concern was reiterated in the 2006 ASCRS White Paper published by Dr L. "Skip" Nichamin and colleagues on "the association between clear corneal cataract incisions and postoperative endophthalmitis".

Obviously, clear corneal incisions are used with all phaco techniques but a risk unique to bimanual MICS was identified in a paper presented by Professor Mikhail Boukhny during the ASCRS annual meeting in 2005. He used Finite Element Analysis (FEA) to compare a bimanual MICS incision without a sleeve, to a coaxial incision with a sleeve. Astonishingly, he found the bimanual MICS sleeveless incision sustained 5.5 times more stress than the coaxial incisions and twice the amount of leakage.

This raises the question: if sleeveless MICS procedures produce more stress and therefore more leaky incisions, are they more prone to compounding the risk of infection?

In addition to these factors, Dr Ismail Hamza presented a video at this year's ASCRS Film Festival documenting 14 cases of corneal wound burn during a one-year period with one of the most widely used systems for bimanual MICS. This represented a 3.5% burn rate out of 400 cases. In contrast, during a recent review of my ten-year experience with the Bausch & Lomb power modulation, including the newest Stellaris Custom Control Software II, I performed 19309 cases with zero cases of corneal wound burn.³