Eyeworld

FEB 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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20 EW NEWS & OPINION February 2012 Complicated cataract cases rePlay online content Phacoemulsification in the white cataract by Nick Mamalis, M.D. T he types of cataracts that pose the greatest challenge to the ophthalmologist include the dense brunescent cataract, the white cortical cataract, and the poste- rior polar cataract. Each type is unique in the specific surgical challenge it poses and the complications that may result. There is a spectrum of behavior for white cataracts. Most of the time they pose no particular threat. However, sometimes they are challenging and require a special approach. The latter occurs when a white cataract is intu- mescent. An intumescent cataract is one that is swollen or congested. The term is often used in reference to sub- stances that swell in response to heat or flames, such as passive fire retar- dants. In the case of the cataractous lens, intumescence refers to swelling or hydration associated with increased in- tralenticular pressure. The problems posed by the white cortical cataract are two-fold. First, it is often difficult to visualize the anterior capsule to perform a capsulorhexis be- cause there is no contrast against the backdrop of a white cataract. Second, the lens capsule may rupture like a bal- loon when the initial capsule puncture is made. In this issue, Dr. Mamalis dis- cusses his approach to improving visualization of the anterior capsule, performing a successful capsule punc- ture and capsulorhexis, and completing the phacoemulsification of a white cataract without complications. Kevin Miller, M.D., complicated cataract cases editor Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) Or view the video of Dr. Mamalis's procedure at www.eyeworld.org/replay.php. Figure 3A. Capsular puncture with a sharp cystotome demonstrating a white plume of liquified cortex Figure 3B. Same patient following aspiration of liquified cortex under the anterior capsule decompressing the lens Source: Nick Mamalis, M.D. O ne of the most difficult anterior segment proce- dures to perform is the re- moval of a white cataract. A mature white cataract may actually have a hard or brunes- cent nucleus underlying it with a flocculent anterior and posterior cortical opacity. The trickiest white cataract to remove is a hypermature or intumescent-type cataract (Figure 1). These cataracts have markedly hydrated swollen lenticular material, which then causes an increase in lens thickness and a relatively tense lens capsule. In the extreme circum- stance, the cortex can completely liquefy and allow the dense nucleus to sink to the bottom of the capsular bag, forming a morgagnian cataract. The most difficult step of cataract surgery in these hyperma- ture intumescent cataracts is per- forming a capsulorhexis or continuous curvilinear capsulorhexis (CCC) without an extension upon the opening of the capsular bag. The white cataract prevents a red reflex that does not allow adequate visuali- zation of the capsule when perform- ing a CCC. Staining of the anterior lens capsule with a stain such as try- pan blue is very helpful in allowing visualization of the capsule without an adequate red reflex. A small stab incision is made at the limbus and air can be inserted into the anterior chamber with trypan blue injected under the air. It is important to paint the anterior capsule in a back and forth movement similar to a windshield wiper when placing the trypan blue. A second way that the capsule can be dyed is a soft shell technique with an OVD injected into the anterior chamber and then a thin layer of balanced salt solution placed on the capsule with the try- pan blue dye placed on the lens cap- sule in this manner. When air is used, the air is then replaced with OVD following staining of the cap- sule. A high molecular weight or a super cohesive OVD such as Healon5 (Abbott Medical Optics, Santa Ana, Calif.) or DisCoVisc (Alcon, Fort Worth, Texas) is recom- mended in the intumescent cataract. This will help to flatten the dome of the capsule and keep the anterior chamber pressurized without leakage of the OVD out of the anterior chamber during the performance of the capsulotomy. If there is any high pressure it is important to avoid puncturing the capsule with a large forceps, as this may cause an uncontrolled tear with the so-called Argentinian flag sign, in which the white cataract is seen in the center and the blue stained capsule on both sides with a tear extending to the equator (Figure 2). This can be minimized by using a sharp cysto- tome to begin the CCC with a very small puncture of the capsule and immediate aspiration of the liquified continued on page 22 Figure 1. Sagittal section of a globe with a white, intumescent cataract Figure 2. Anterior capsular tear extending to the equator with trypan blue dye demonstrating the Argentinian flag sign

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