Cataract surgery more challenging after violation of posterior lens capsule

In this case, a vitrector damaged the capsule during previous pars plana vitrectomy.

Issue: June 25, 2016

ByUday Devgan, MD

In routine cataract surgery, the posterior lens capsule plays a pivotal role: It acts as a barrier to separate the anterior segment from the vitreous cavity, it supports the cataract nucleus during phacoemulsification, and it holds the IOL securely at the end of the case. But how can you safely and successfully remove a cataract and implant the IOL when it has been violated?

The case presented here is certainly challenging because of the patient’s history. She suffered a retinal detachment that required a pars plana vitrectomy to repair it. The retina surgery was challenging, and while removing anterior vitreous, the posterior capsule was inadvertently touched with the vitrector. The retina was successfully reattached, but shortly after the patient developed a significant cataract.

While this patient may not have had a complete perforation of the posterior capsule, keep in mind that at just 4 µm thin, any damage to it is likely to result in compromise in the support of the nucleus and a danger of displaced nuclear fragments into the vitreous cavity. How should we proceed? A pars plana lensectomy is possible, but the patient will still need an incision into the anterior segment in order to insert the IOL. If we can do the entire cataract removal and IOL insertion via the anterior segment, it is a better and less invasive option.

A decision was made to do an approach from the standard cataract incisions with the understanding that, if needed, the patient could have a pars plana lensectomy done at the same sitting by the retina team. Trypan blue dye was used to stain the anterior capsule to assist in visualization during capsulorrhexis creation (Figure 1a). Care was taken to create a round, well-centered, appropriately sized continuous capsulorrhexis because it would likely be providing the support for our IOL.

With the defect of the posterior capsule, any steps that cause pressure or stress to the capsule must be avoided. This means that minimal hydrodissection was done, primarily in areas away from the capsular defect (Figure 1b). We avoided using a forceful wave of fluid because this could have blown out the posterior capsule.

Figure 1. Trypan blue is used to aid in creation of a capsulorrhexis in the anterior lens capsule (a). There is a posterior capsule defect from the prior pars plana vitrectomy at the 10 o’clock position so minimal hydrodissection is done (b). The chopper is used to hook the cataract equator and bring the nucleus out of the capsular bag (c). Viscoelastic is injected to stabilize the nucleus and create a barrier between it and the violated posterior capsule (d).

Figure 2. With the viscoelastic cannula impaling the nucleus, the chopper is used to break the nucleus into halves (a). These are then broken into quadrants and removed using the phaco probe (b). While the nuclear pieces are being phaco-aspirated, viscoelastic is injected under the fragments to prevent them from falling posterior (c). Irrigation and aspiration of the cortex is easier because these pieces are adherent to the capsule and are not likely to fall into the vitreous cavity (d).

Figure 3. Because the patient had a prior pars plana vitrectomy, there is no risk of vitreous prolapse, so the viscoelastic is used to open the ciliary sulcus (a). The three-piece IOL is placed on top of the iris (b), and then the haptics are dialed into the ciliary sulcus and the optic is captured through the capsulorrhexis (c). A suture is placed to close the incision securely (d).

For nucleus removal, the most important issue is to avoid doing the typical divide-and-conquer technique. Even the stop-and-chop or in-the-bag chop techniques can cause too much stress on the weakened capsular bag and risk causing a large capsular rupture and loss of the nucleus into the vitreous cavity. Instead, use the chopper to hook the equator of the cataract and bring the entire nucleus up and out of the capsular bag (Figures 1c and 1d). The nucleus will then pose no stress on the posterior capsule, and additional viscoelastic can be used to stabilize it as well as create a barrier in front of the posterior capsule. Alternate methods for this case include using a scaffold technique with the IOL optic or a plastic barrier, but both of these would still require the maneuver of using the chopper to bring the nucleus out of the capsular bag.

Avoid placing the phaco probe in the anterior chamber with the typical high bottle heights that are used for nucleus removal. This is because the infusion pressure can cause stress on the posterior capsule and lead to a large rupture and a dropped nucleus. Instead, use the viscoelastic cannula to impale the nucleus and then chop it into quadrants (Figure 2a). These nuclear pieces can now be removed with a lower bottle height and lower infusion pressure while more viscoelastic is injected behind the nuclear fragments and in front of the posterior capsule (Figures 2b and 2c).

Cortex is easier to remove because it is adherent to the capsule. Using the irrigation/aspiration probe, remove the cortex piece by piece until the capsular bag is empty. The posterior capsule defect may enlarge during this step, but as long as the anterior capsular rim is intact, we will be able to adequately support the IOL. Because the patient had a prior pars plana vitrectomy, there is no risk of vitreous prolapse into the anterior segment. At this point, with the eye aphakic, we can use the indirect ophthalmoscope to inspect the vitreous cavity and retina to make sure that there are no retained lens fragments.

For this case, we chose a three-piece monofocal acrylic IOL for placement in the ciliary sulcus (Figure 3). Viscoelastic was injected under the iris and in front of the anterior capsular rim in order to expand the sulcus space. The IOL was then injected into the anterior chamber and on top of the iris so that each individual haptic could be carefully placed into position. Using the chopper, the IOL haptics were dialed into the sulcus and found to have good support. The 6-mm diameter optic was then securely captured through the 5-mm capsulorrhexis for long-term stability. Finally, the viscoelastic was evacuated, and the incision was closed with a single 10-0 nylon suture.

The patient recovered excellent vision from the cataract surgery and was very pleased with her outcome from this challenging case.

For more information:
Uday Devgan, MD, is in private practice at Devgan Eye Surgery, Chief of Ophthalmology at Olive View UCLA Medical Center and Clinical Professor of Ophthalmology at the Jules Stein Eye Institute, UCLA School of Medicine. He can be reached at 11600 Wilshire Blvd. #200, Los Angeles, CA 90025; email: devgan@gmail.com; website: www.DevganEye.com.

Disclosure: Devgan reports no relevant financial disclosures.