gently grasped immediately adjacent to the tear, and guided back with a careful movement directed centrally. If an anterior tear cannot be turned back toward the center using the forceps, a small area of the can opener technique can be utilized to remove this section of the capsule. Then a small strip of capsule encompassing a short tear can be created to avoid radial extension of the tear.2,23,32 If the tear cannot be turned back, and it extends well into the equator, the capsulorrhexis can be completed from the opposite direction (Fig. 5–3C). This type of rhexis is obviously not continuous. Therefore, in this situation, or anytime a capsule tear disappears under the iris such that its peripheral extent cannot be visualized, the surgeon must expend due care to prevent the extension of the tear around the equator and into the posterior capsule. In this circumstance, excess pressure during hydrodissection, phacoemulsification, and cortex removal, all of which may cause the tear extension, must be avoided. Additional principles of management in these cases are discussed below.

CAPSULORRHEXIS TECHNIQUE

FOR SMALL-PUPIL CASES

In small-pupil cases the use of a centrally directed tearing motion may move the side of the lens into view and enhance the visibility of a capsulorrhexis edge that is larger than the pupil opening. In this setting extreme care must be taken to ensure that, at the completion of the rhexis the ends of the tear overlap, that is, the tear is completed from the outside toward the inside of the capsule edge. This will ensure that there are no nicks, or triangular edges, in the capsule. During later steps in the procedure the angled edge has the potential to extend peripherally. It may be helpful, in addition, to use a second instrument through the paracentesis to gently push the iris aside for better visibil-

ity. The use of additional viscoelastic between the iris and anterior capsule is another method to lift and help enlarge the pupillary aperature.33,34 Although, some surgeons may be able to accurately assess the location of the tear by noting the location of the folding of the anterior capsule as the CCC proceeds, even if it is hidden by the iris, direct visualization of the CCC as it is being performed is recommended.

If the pupil is too small for these measures it should be enlarged with one of the methods described in Chapter 6.

If the resulting CCC is too small, it can be enlarged by using Gills-Walsh Vannas scissors directed in a tangential counterclockwise direction to begin a slightly more peripheral tear (Fig. 5–4A). Care should be taken not to close the scissors completely as the tips closing will create a jagged end to the snip. The new flap edge created in this way can then be directed using a forceps (Figs. 5–4B–E).

CAPSULORRHEXIS SIZE

There is debate regarding the optimum size for the capsulorrhexis. Three significant factors that determine CCC size are (1) the relationship of the capsular opening to the size and maturity of the cataract, and the expected phaco procedure to be performed;

(2) the size of the optic of the anticipated IOL; (3) anatomic abnormalities of the zonules.

CATARACT SIZE AND TYPE

The rhexis opening must allow adequate access to the cataract. In cases of nuclear mature, hard brown cataracts, too small a rhexis predisposes to rupture of the posterior capsule during the hydrosteps (see Chapter 7). Nuclear manipulation is facilitated by the creation of a larger rhexis. The likelihood of cre-

ating a tear in the anterior capsule during phaco is minimized with additional size for maneuvering. Should a tear occur, however, the risk of more significant complications exists. The tear does not have to extend very far to progress to or through the equator and destabilize the remaining anterior capsular support for a sulcus-placed IOL.

In the case of white, cortically mature cataracts, a smaller CCC may be acceptable. This is discussed in greater detail below.

IOL OPTIC SIZE

In relation to IOL optic size, some surgeons feel that the capsulorrhexis should be larger than the optic and advocate the use of a large (5.5 to 6 mm) capsulorrhexis. The anterior and posterior capsules are then polished. A modified chalazion curette is utilized to clean lens epithelial cells.23 Postoperatively this will permit the edge of the anterior capsule to adhere to the posterior capsule, and produce a Soemmering’s ring. The theory is that the resultant effect will be the creation of a seal with subsequent isolation and inability of the lens epithelial cells to migrate across the posterior capsule.23

Others, including the authors, recommend that the CCC should be slightly smaller and concentric with the IOL, so that no portion of the anterior capsule CCC edge can fuse to the posterior capsule. The IOL edge therefore creates a mechanical barrier to lens epithelial cell migration behind the IOL. This theory is confirmed by the decreased incidence of YAG capsulotomy seen in association with the thick angular edge of the Alcon Acrylic MA 30 or 60 IOL. In addition, concentric placement balances the forces of the contracting capsular bag, hence minimizing the tendency for postoperative IOL movement.

Asymmetrical CCC will result in part of the CCC being over the IOL and part being larger than the IOL and therefore over the posterior capsule. This often may lead to subsequent asymmetrical fibrosis, which often will nudge the lens to an eccentric position. In addition, where the anterior and posterior capsule are in contact there will be fusion of the capsule. This is often the initial site where lens epithelial cells can migrate across the posterior capsule, resulting in folds or a fibrous thickening and opacification of the posterior capsule.

A second reason that we favor a CCC smaller than, and concentric with, the optic is to maintain the compartmentalization of the eye even after

Nd:YAG laser posterior capsulotomy. In a study that we performed, we found that the initial pressure spike after Nd:YAG laser capsulotomy did not occur when the lens was completely sequestered in the capsular bag.6 There was a significant pressure spike when the lens was in the sulcus or when the IOL optic was partly in the bag and partly out of the bag. We postulate that the sequestering of the anterior chamber by the seal created when the optic of the IOL is completely covered by the capsulorrhexis becomes a barrier against liquefied vitreous coming into the anterior chamber. This may also reduce the possibility of pseudophakic glaucoma.

The third reason to advocate a CCC smaller than the optic is, in the event of a posterior capsule tear, the technique of sulcus placement of the loops and optic capture through the CCC, as proposed by Neuhann (unpublished data), can be utilized. If the capsulorrhexis is larger than the IOL optic, this technique cannot be utilized. Additionally, the more remaining capsule existing for sulcus IOL support, the easier sulcus placement becomes.

The ideal CCC size therefore, would allow 1⁄4-mm overlap of the capsule over the IOL edge. For a 5.5- mm optic IOL, this would be a rhexis of 5 mm, and for a 6-mm IOL the size would be 5.5 mm.

ANATOMIC ABNORMALITIES

OF THE ZONULE

In cases of pseudoexfoliation, weak zonules, and excessive inflammation, the anterior capsular edge may fibrose and contract, creating the capsular contraction syndrome. This may necessitate the use of the YAG laser to incise/excise the thickened capsular rim.35

In addition, Davison has described the capsular block syndrome. It occurs in the presence of a small capsulorrhexis and with implantation silicone or acrylic IOLs. In the postoperative period, there is accumulation of unknown material between the IOL and the posterior capsule. The material accumulates enough volume and pressure to eventually push the posterior capsule posteriorally and the IOL anteriorally, resulting in induced myopia. The syndrome is treated by YAG capsulotomy of the posterior capsule. The resultant equalization of pressure permits the posterior capsule and IOL to return to their normal pseudophakic configuration.36 A similar material may accumulate behind the MemoryLens material. It is opalescent and will not substantially increase bag pressure, anteriorally displace the IOL, or change refractive error. YAG posterior capsulotomy will release the material into the vitreous with no adverse outcomes (W. J. Fishkind, unpublished data).

CONTINUOUS TEAR CAPSULORRHEXIS

WITH THE INTUMESCENT CATARACT

Mature cataracts pose a challenge for performing complication-free capsulorrhexis due to the difficulties encountered in visualizing the edge of the tear. Visualization can be limited due to a poor red reflex and may be further compromised by liquefied cortex, which may flow into the anterior chamber, as soon as the initial puncture is made.

Methods of improving visualization include slowing the microscope focus to obtain precise control, dimming the operating room lights, and using high magnification with increased coaxial lighting. A small-gauge cannula may be helpful in removing the opaque liquefied cortex to further enhance visualization during CCC. A method of turning off the microscope and room lights and then using a light pipe to provide side light to illuminate the tearing capsular edge has been described by Gills22 and Masket.25

A major improvement in CCC for the white cataract has been the description of the use of indocyanine green (ICG) (Akorn) dye. This dye is mixed according to the directions; 0.5 cc of diluent is mixed with the contents of the ICG vial. This mixture is then diluted with 4.5 cc of BSS. Then 0.1 cc is injected over the anterior capsule under an air bubble using viscoelastic at the incision to prevent egress of the air bubble. After waiting a moment both the dye and air are irrigated from the AC. The anterior chamber is then filled with viscoelastic and the capsule may then be easily identified for the performance of the capsulorrhexis.37

Alternatively, Trypan Blue Stain can be utilized in a similar process. Trypan Blue comes in 1-cc unit dose vials of 0.1% solution in phosphate-buffered sodium chloride (Gurr, BDH Laboratory Supplies). It is reported that Trypan Blue provides better visualization of the anterior capsule during both capsulorrhexis and phacoemulsification.38,39

Not infrequently in white, mature, cataract cases a small capsulotomy may be more safely achieved than a large one. The nucleus with liquefied cortex may be under pressure. The initial entry into the capsule may be followed by the egress, through the capsular opening, of the liquefied cortical material. This may occur with sufficient pressure to extend the small penetration to a radial tear. Therefore, before penetrating the capsule the anterior chamber must be adequately filled with a retentive viscoelastic. Once liquefied cortex has been removed, the intracapsular volume has been decreased, and the capsular edge can be visualized, the rhexis can be enlarged. This is performed as described above after filling the capsular bag and anterior chamber with