When the capsule breaks: PCCC

Become adept at the posterior capsulorhexis, and the procedure will reward you.

By Lisa Brothers Arbisser, MD

Avoiding posterior capsule (PC) rupture with in-the-bag IOL implantation is the gold standard in cataract surgery today. When the surgeon inadvertently breaks the capsule, then conferring stability should be the next step: One should convert a noncontinuous rent into a continuous curvilinear tear. Beyond this indication, eyes presenting with so-called unpolishable plaques deserve a posterior capsulorhexis (PCCC) for immediate visual recovery.

Many advantages exist for a planned PCCC, allowing Berger’s space for implantation — an old idea whose time has come.

PC management has been invaluable in my practice, benefiting pediatric cataract patients and adults who require general anesthesia for Nd:YAG laser capsulotomy. Surgeons such as Rupert Menapace, MD in Vienna and Marie-Jose Tassignon, MD in Antwerp use PCCC routinely. Every surgeon should be facile, if only for capturing subluxated intraocular lenses (IOL) achieving the best outcomes for complications.

PC summary

The posterior capsule is 4u to 6u thick and more elastic than the 14u to 16u anterior capsule. The zonular network’s interdigitated fibers bind the capsular bag completely around its equator. The posterior zonular attachments and Wieger’s ligament respectively define Berger’s space and, peripherally, the space of Garnier. In the surgical view, the PC is above and the hyaloid membrane below. Berger’s may be real or potential in the natural state, often requiring definition with an ophthalmic viscoelastic device (OVD) to adequately separate the anterior vitreous face from the PC for safe manipulation.

Immediate recognition of complications during cataract surgery affords an opportunity to limit the damage. Upon a breach, the surgeon should stabilize the anterior chamber with dispersive viscoelastic through the paracentesis — before removing irrigation devices to prevent collapse of the anterior chamber and progression of the tear.

If the tear is large and extends beyond the anterior capsulorhexis (ACCC) little hope exists of accomplishing a PCCC. The usual steps of identifying and handling vitreous loss should then ensue using a three-piece IOL for sulcus implantation and optic capture through the ACCC.

Step by step

Once the chamber is stabilized, the next step is exploration of the tear within the confines of the anterior rhexis. This is done by instilling OVD through a cannula placed at the tear’s entrance. This will show the OVD either visibly falling down into the posterior segment, indicating a rupture of the vitreous face, or accumulating into itself, defining the circular Berger’s space as the fragile hyaloid is displaced posteriorly. Perform a biaxial automated vitrectomy if the hyaloid is broken and the vitreous prolapsed. Irrigation is placed through the paracentesis and the vitrector is ideally placed through a pars plana incision to best avoid enlarging the PC tear. Triamcinolone acetonide (Triesence, Alcon) is used to confirm the vitrectomy endpoint and the chamber is controlled once again with OVD prior to proceeding with PCCC. As long as prolapsed vitreous is present at the edges of the tear, a PCCC cannot be reliably accomplished.

Once the hyaloid is intact, with Berger’s space defined, or the prolapsed vitreous is removed, place more OVD over the peripheral iris to flatten the anterior capsular rim with the PC in a planar position to convert to a PCCC.

On high magnification with a well-coated corneal surface allowing visualization, the surgeon then grasps an edge of the tear with Utrata forceps. Unlike the anterior capsule, the PC behaves more like pediatric elastic tissue so a centripetal vector of force must be applied to properly direct the tear. Often, as in pediatric ACCC, the last few millimeters of the rhexis require a Gimbel-described “little rescue maneuver;” pull the flap backwards towards the direction of the tear to complete the circle and detach the flap. If no edge is available, create one with Vannas or intraocular scissors prior to the use of the forceps. Please note: when a punched-out tear appears round, it will not have the strength of a continuous rhexis and must be converted for safe in-the-bag IOL implantation.

Figure. Implant buttonholed into Berger’s space. Note oval PCCC edge from haptic to haptic junction and undisturbed round ACCC edge.

Once the PCCC is completed, the capsular fornix is opened with cohesive OVD; this will permit implantation in the bag. Careful visualization and controlled delivery of the foldable lens is required to confirm the leading haptic enters the bag fornix and not below the PC into the vitreous cavity.

Flaps, cat eyes and buttonholes

For visually significant plaques, the PCCC must be initiated electively to spare the patient delayed visual rehabilitation until sequential Nd:YAG laser capsulotomy can take place. This is only attempted when an intact ACCC — sized for optic capture from the sulcus — is confirmed in case difficulty is encountered. Only plaques without fibrosis beyond the area to be included in the PCCC are candidates because a fibrotic capsule won’t predictably tear.

Once the PC is planar, use a bevel up, 30-g hypodermic needle on a TB syringe to lift the PC upward at the edge of any fibrosis; pierce it and push upward, which will produce a curvilinear flap. A cystotome should not be used as the hyaloid may be closely applied to the PC and both would be inadvertently opened by the downward-facing barb. Once the flap is initiated, use forceps to create 4 clock hours of the PCCC. Then, use cohesive OVD to push the hyaloid back, defining Berger’s space in the process. The PCCC is then completed as described above. This dissection of the lens-vitreous interface makes room for the intrusion of the optic into Berger’s space without breaking the vitreous face, which can result in vitreous herniation around the lens.

A surgeon has two choices: to make the PCCC small and confine it to the area of opacity so it is central for bag IOL implantation; or to guide the tear so it is concentric and just slightly smaller than the ACCC. This allows the bag haptic placement with optic capture posteriorly through the PCCC into Berger’s space. Perfect size and centration aren’t required as the PC is forgiving; the lens’ central placement is based on the haptics placed in the bag. The optic is gently pressed downward so the elastic PC wraps around the optic periphery in between the haptic junctions. A cat-eye pattern is seen with the distended capsule and the optic forming a mechanically stable and watertight diaphragm. This strategy is known as “posterior optic capture” or “posterior buttonhole (POBH).”^1,2

If the IOL is not captured in the bag, the bare anterior hyaloid face must be protected during OVD removal by holding the lens back with an instrument through the paracentesis, placing acetylcholine chloride intraocular solution (Miochol-E, Bausch + Lomb) into the chamber for miosis, and never allowing the anterior chamber to shallow while securing incisions. If the lens is buttonholed, OVD can be aggressively removed from the anterior chamber but prevent chamber collapse, which might uncapture the optic. The posterior chamber is never evacuated of OVD; any residual behind the optic will not cause a pressure rise or a bag distension syndrome when the PC is open.

Planned technique

The technique for planned manual PCCC is mostly the same as above. One difference: the flap can be initiated centrally with the 30-g needle rather than on the edge of fibrosis for plaques.

Manual PCCC is a challenging technique with about a 150-case learning curve. An automated posterior capsulotomy can be performed by the off-label use of the femtosecond laser.³ After receiving standard femtosecond laser assisted cataract surgery, 81% of adults re-docked in a sterile manner have Berger’s space visualized, which allows a posterior capsulotomy without hyaloid rupture. The PC flap shrinks out of the visual axis by day one.4 Other automated modalities in the FDA pipeline may facilitate this technique.

Is it safe?

Studies by Neuhann, Gimbel, Tassignion and Menapace have shown that the hyaloid provides protection from posterior segment complications and that the PC is redundant. Long-term follow-up shows no greater risk of macular edema or postoperative pressure rise than those with intact PC. Retinal detachment may prove to be less common when the optic is buttonholed due to the stabilization of the anterior hyaloid for life by the posteriorly positioned optic and the absence of need for Ng:YAG capsulotomy.

Why would someone go to so much trouble electively? We can consider the case complex with the associated codes when performing a PCCC, a small carrot. This is not monetarily optimal in a fee-for-service world when we will eliminate fees for Ng:YAG laser capsulotomy in nearly all patients with the primary PCCC and in 100% of patients with a buttonholed lens. The edge of the posterior capsule lies on top of the anterior optic surface, so migrating lens epithelial cells cannot gain access to the retrolental space, even in children. But, consider this outside of the economic model today in the United States — imagine these benefits for the developing world.

Conclusion

This extra maneuver will provide a lifetime of clear vision and avoid a second period of visual degradation. Stray light testing with no capsule compared to a “clear” capsule with 20/20 Snellen acuity is better. Ng:YAG laser capsulotomy invariably breaks the hyaloid, which can lead to floaters, risk of macular edema, retinal detachment and ocular hypertension. The posterior position of the IOL stabilizes the vitreous and also allows more room for refractive piggyback lenses, which is especially important in pediatric cataracts. Lens epithelial cell metaplasia and fibrotic whitening and shrinkage of the anterior capsule occurring with IOL- epithelial cell touch is avoided. Centration is bag dependent and doesn’t change over time resulting in stable refractions from day one. With adequate anterior capsule polishing, clear and possibly flexible anterior capsules, running equator to equator, may eliminate late bag-lens subluxation associated with phimosis. There is no need for square implant edges reducing dysphotopsia and opening the way to new lens designs. There may be many more ramifications that inform my own research.

When I am ready for cataract surgery, I wish to have my IOLs in Berger’s space. OM

REFERENCES

About the Author
	Lisa Brothers Arbisser, MD, teaches cataract and anterior segment surgery worldwide from her Quad Cities, Iowa and Illinois practice, Eye Surgeons Associates, where she is now emeritus. She serves as adjunct associate professor at the University of Utah Moran Eye Center.