In my previous article “
Capsulorrhexis Basics”, I reviewed the steps for creating a continuous curvilinear capsulorrhexis (CCC). Even after becoming proficient at creating a CCC, it is impossible to make a perfect one every time. For the beginning surgeon, choosing appropriate patients will make the learning process much easier (i.e., bright red reflex, wide pupillary dilation, good patient cooperation). Nevertheless, even seasoned surgeons sometimes encounter problems, so it is important to know how to anticipate, prevent, and manage such situations:
Instrumentation: the capsulorrhexis is easier to master and quicker to complete with forceps than with a cystotome. However, I prefer to create the entire CCC with a cystotome for a number of reasons, especially under topical anesthesia: 1) using a cystotome avoids changing instruments if a cystotome is already used to create the initial capsulotomy, 2) the cystotome can be attached to a vial of viscoelastic (OVD) so that more of it can be injected to maintain the anterior chamber during the capsulorrhexis if necessary, 3) the thinner cystotome is easier to maneuver and induces less wound distortion and corneal striae, and 4) if the patient suddenly moves his or her eye, the surgeon cannot release the grasp on the capsule with forceps fast enough to prevent the tear from extending peripherally, whereas, a cystotome will simply lose contact with the capsule, preventing a peripheral tear (although this is rare, I have seen it happen). This latter scenario can also be avoided by stabilizing the eye with a second instrument at the paracentesis during the capsulorrhexis.
Another option is the Fugo blade, an easy to use plasma knife that creates a capsulotomy quickly and accurately.
Size: appropriately sizing and positioning the capsulorrhexis requires practice, but there are some aids for this. The pupillary border serves as a reference for making a round, central CCC, and thus the capsular tear should be maintained at a constant distance from the edge of the iris for 360 degrees. A 6mm optical zone marker can also be used to place an ink ring on the cornea to serve as a guide for the rhexis, or Seibel capsule forceps with mm marks can be used to gauge the size. If the capsular opening is too small or off center prior to completing the capsulorrhexis, it can be corrected by spiraling the tear outward to the appropriate diameter and position. Alternatively, this can be accomplished after IOL implantation by cutting the edge of the capsule obliquely to create a dog-ear that is grasped and torn.
Visualization: it can be difficult to see the edge of the capsulorrhexis if the red reflex is absent. Staining the anterior capsule with ICG or trypan blue eliminates this problem. If these capsular dyes are unavailable, then oblique light is helpful (i.e., turning off the microscope light and using a hand held vitrectomy light pipe angled toward the pupil). If the pupil is too small, it is safest to enlarge it to a diameter adequate for the desired size capsulorrhexis. However, for borderline cases, the CCC can be created blindly under the pupillary margin by carefully leading the folded flap around in a circle slightly larger than the pupil. A microhook can also be used as a second instrument to retract the iris ahead of the capsulorrhexis in order to visualize the tear.
Salvage: there are several methods of saving a CCC if the capsule tears peripherally. A peripheral extension of the tear occurs when it runs “downhill” toward the lens equator. This typically happens if the anterior chamber becomes shallow but can also occur if the rhexis is torn too far into the lens periphery. To redirect the tear, one or a combination of maneuvers should be performed: flatten the lens by refilling the anterior chamber with OVD or by gently pressing on the lens with a spatula, pull backward and centrally on the flap to create an abrupt change in direction toward the center of the lens. An alternative is to restart the capsulorrhexis in the opposite direction from its initiation point by cutting the edge to create a dog-ear. Finally, a can-opener capsulotomy can be used to complete the opening.
Since all steps of cataract surgery affect subsequent steps, it is important to create a good capsulorrhexis. A poor one makes the surgery more difficult and increases the risk of a complication. The techniques described above can be mastered with practice. Ultimately, an appropriately sized and placed capsulorrhexis improves postoperative refractive results because a predictable IOL location increases the accuracy of IOL calculations.
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