You’ve seen countless videos of phaco chop, but you seem to be stuck in a mode of less efficient techniques of nucleus removal. How do you advance to the next stage of nucleus disassembly during phaco surgery?
Over the past 20 years of teaching ophthalmology residents, I have learned that it takes a resident about 100 cataract surgeries to develop sufficient intra-ocular skills to progress to phaco chop. This varies and some residents are able to perform phaco chop earlier in the learning curve while others may defer advancing their skills until years later. But I am convinced that any ophthalmologist in training can learn phaco chop. And this also applies to surgeons already in practice, too.
For the first few phaco chop cases, choose a patient with sufficient nuclear density, somewhere in the 2+ to 3+ range. This allows the chop to propagate but it is not so dense as to become fibrous and difficult to separate. The phaco tip needs to show enough metal to bury the tip into the nucleus (until the silicone sleeve touches the nucleus).
For initial phaco parameters, try these as a starting point:
- Use a 19 gauge phaco needle, either bent or straight, 30 degrees
- set the vacuum level high enough to have holding power, at least 350 mmHg
- a good starting flow rate is 30 cc/min
- choose an infusion pressure (or bottle height) to give sufficient inflow (85 mmHg or 100 cm bottle height)
- phaco power should be sufficient to embed the tip (30 to 50% starting)
- use of phaco power modulations is up to surgeon preference
The phaco tip is embedded into the central nucleus, just inside the sub-incisional capsulorhexis. The chopper is then carefully placed around the lens equator (for horizontal chop), within the central dense nucleus (vertical chop), or in the mid-periphery of the nucleus (combo chop).
The phaco probe is then held relatively still while the phaco chopper begins to split the nucleus, then the phaco probe is used to help fully separate the pieces. You must make sure that the nucleus is being held with high vacuum during this process.
The most critical key is that you only have a window of about 1 or 2 seconds in which to accomplish this chop. Once the vacuum level drops, the nucleus is no longer being fixated, and the chop is likely to fail.
Click below to see a video of a beginning surgeon successfully performing phaco chop: