This patient has 2 congenital problems: a unilateral posterior polar cataract, which is likely associated with mild amblyopia, and zonular weakness, which may have been further compromised by the trauma. In 1990, Osher and coauthors1 reported that posterior polar cataract is associated with a higher incidence of posterior capsule tear because of a defective posterior capsule. These cases are challenging in their own right, and a key to successful management is to avoid placing any mechanical stress on the capsule. Surgical removal of a loose cataractous lens is also technically challenging, yet some techniques and devices that facilitate surgery may be contraindicated when a posterior polar cataract is present. Vigorous hydrodissection, viscocleavage, and insertion of a CTR may result in rupture of a fragile posterior capsule. Nevertheless, phacoemulsification with endocapsular fixation of an IOL is our preferred choice.
We would construct a near clear corneal incision and then fill the chamber with sodium hyaluronate 2.3% (Healon5). Overfilling should be avoided as this alone has been shown to blow out a posterior capsule when a posterior polar cataract is present (V. Centurion and coauthors, “Posterior Polar Cataract,” Video Journal of Cataract and Refractive Surgery, volume 17, issue 2). Alternatively, Viscoat could be used, which is a better tamponade or restraint for vitreous. Viscoat could be placed over the exposed hyaloid, after which the anterior chamber would be filled with Healon5 in a reverse soft-shell technique.2 We would stain the capsule with indocyanine green or trypan blue. Iris hooks or an Ahmed segment for anterior capsule support should be available to stabilize the lens intraoperatively. We would avoid vigorous hydrodissection and would favor gentle multimeridional fluid waves that do not extend beyond the equator. We would not place a CTR at the beginning of the procedure as we prefer to wait as long as possible before inserting the device. Slow-motion phacoemulsification using low parameters and low bottle height will minimize the turbulence and pressure in the anterior chamber. If the lens is severely mobile, a Cionni ring or Ahmed segment may be required to stabilize the bag for long-term IOL centration. The capsular bag could be fully expanded with an OVD in the hope of preventing the CTR from dragging the bag and tearing the weakened central capsule. Cortical removal can be performed with a silicone I/A tip with low fluidics. Alternatively, inflating the capsular bag with an OVD and using a dry technique to remove the cortex would be an effective approach.
Once the nucleus and cortex have been removed, we would fully expand the capsular bag with OVD to facilitate insertion or injection of a standard CTR, Ahmed segment, or Cionni CTR. We prefer to inject a single-piece acrylic IOL that can be maneuvered, given its small profile, in the capsular bag without placing stress on the equatorial capsule. The haptics are very soft and flexible and will not fully expand until the OVD has been removed with the silicone I/A tip, first evacuating the capsular bag and then the anterior chamber. Before removing the silicone I/A tip, we would introduce a 30-gauge cannula through the stab incision, injecting acetylcholine chloride (Miochol) or carbachol (Miostat) and, if necessary, restraining the optic to prevent chamber collapse as the I/A tip is withdrawn. Miostat will provide approximately 48 hours of IOP control in cases in which OVD may be inadvertently retained behind the iris.
Hickem's Dictum states that a patient can have as many diseases as he or she pleases! A posterior polar cataract combined with zonular weakness presents a monumental challenge to the cataract surgeon, but we believe this approach gives the surgeon the best chance of achieving a successful outcome.
1. Osher RH, Yu BC, Koch DD. Posterior polar cataracts: a predisposition to intraoperative posterior capsular rupture. J Cataract Refract Surg 1990; 16:157-162
2. Arshinoff S. Ultimate soft-shell technique and AcrySof Monarch injector cartridges [letter]. J Cataract Refract Surg 2004; 30:1809-1810