There are many challenges associated with phacoemulsification of intumescent white cataracts: The opaque lens material blocks the red reflex and hinders visualization of the capsule, the nuclear material may be quite dense, and there is a tendency for the capsulorrhexis to become errant, which can result in complications such as vitreous prolapse.
Using trypan blue dye, we can stain the anterior lens capsule to aid in visualization during capsulorrhexis creation. With phaco power modulations and variants of the phaco chop technique, we can safely remove even dense nuclei while limiting the ultrasonic energy used. But perhaps the biggest challenge is avoiding the runout of the capsulorrhexis, which can result in the “Argentinian flag sign.” This syndrome gets its name from the appearance of the capsule and cataract after the capsulorrhexis has been lost and three stripes appear: a middle stripe of white cataract flanked by the remainder of the anterior capsule, which has been stained blue.
We can avoid losing control of the capsulorrhexis by managing the pressure gradients that exist within the capsular bag. For an intumescent cataract, the cortical lens material has become white due to denaturing of lens proteins and it has become liquefied, hence the name intumescent. With this fluid within the capsular bag, it becomes more challenging to perform the capsulorrhexis as compared with operating on a solid cataract.
Techniques have been described to release this fluid, such as using a sharp needle to pierce the anterior lens capsule and then aspirating via a syringe or using the phaco probe to puncture a round hole in the anterior lens capsule to remove fluid before capsulorrhexis creation. Both of these techniques will work because they release the pressure gradient that exists within the capsular bag. My preferred technique allows the surgeon to be in control of the pressure within the anterior chamber as well as in the capsular bag, and it gives great control during capsulorrhexis creation.
With a single paracentesis incision made in the eye of 1 mm or less in width, the anterior capsule is stained with trypan blue dye and then the anterior chamber is filled with viscoelastic. The key at this point is to ensure that the anterior chamber is highly pressurized, more than in a typical cataract surgery. We need to make sure that the pressure within the anterior chamber is higher than the intracapsular pressure that is created due to the trapped liquefied cortex.
- Click here to read the full publication exclusive, Back to Basics, published in Ocular Surgery News U.S. Edition, June 25, 2017.