Handling the drama of the traumatic cataract patient

by Maxine Lipner

It's classic high drama - a patient has been struck in the eye and now has a traumatic cataract. Here are some insights on how to proceed.

When dealing with a traditional cataract, there is plenty of time for a practitioner to plan the next move and determine how to handle the situation. But, what about the patient with an acute injury to the lens? Unfortunately, practitioners must decide on the spot whether to proceed and how to maximize visual outcome.

"The incidence of traumatic cataract with penetrating injury is significant," said M. Bowes Hamill, MD, PhD, associate professor of ophthalmology at Baylor College of Medicine, Houston. "This is a management problem that we have to address every time we are faced with a patient with a penetrating globe injury," he said. The practitioner faces a series of choices. First comes the question of whether to repair the cataract simultaneously with primary repair or to do a secondary repair. Second, if the repair is done simultaneously, the practitioner must decide whether to implant an intraocular lens at that time, Hamill said.

Taking a traumatic pause
"Just because there is a cataract, doesn't mean that it has to come out - at least not right then," Hamill said. He finds that isolated anterior capsular breaks, especially if they are not in the visual axis, can heal quite nicely without surgical intervention. Likewise, concussive cataracts will also heal with time, especially if they are off-axis subanterior capsular cataracts.

There are only a couple of occasions when cataract surgery is ever an emergency, Hamill said. "One is lens dislocation causing pupillary block glaucoma and the other is an intumescent lens causing angle-closure glaucoma," he said. In both cases, the lens is removed, but not because of the cataract - it is removed to treat the secondary glaucoma.

Determining whether to do a primary or a secondary procedure is a matter of weighing the advantages and disadvantages. There are several advantages to primary cataract extraction, which can be done as one procedure along with the trauma repair. "There is a lot less anesthetic risk, and there is early visual rehabilitation that may be important with pediatrics," Hamill said. In addition, patients with problems returning for follow-up may appreciate the one-step procedure, he said.

"Another advantage is that we can get that opaque lens material out of the way," Hamill said. "That allows us to really get a good look at the posterior pole by direct visualization, which, by any measure, is certainly better than an indirect measure." One final advantage to a primary extraction is the large pupil access. "If you are going to do an iris repair at the same time, especially if you do a pupilloplasty, you may not be able to get a big pupil again, so cataract surgery may be difficult," Hamill said.

There are also numerous disadvantages to primary removal, however. One is the ability at the initial evaluation to always determine whether a cataract is visually significant.

"We may see a lens opacity and think it's significant, but is it really going to cause loss of vision?" Hamill asked.

Also, a primary cataract extraction is harder to do at the time of the primary repair than would be a secondary procedure. Practitioners also don't know the status of the zonules and may not be able to see through the corneal pathology to get all the cortical remnants out or to do the procedure as well as they'd like, Hamill said.

The ophthalmologist must then decide what to do about the IOL. Positioning the lens in the bag is clearly preferable, especially in younger patients who are at particular risk for injury, Hamill said. "You don't want to put angle-supported lenses in young patients; they just don't do well, both for glaucoma risk and for secondary scarring," he said. "I think that there are also some concerns with putting ciliary sulcus lens implants into younger kids, especially if we have an option."

There can, however, be hurdles to overcome. The practitioner frequently doesn't know the status of the zone at the time of the initial closure. There's also the potential of harboring bacteria on an implant as it is slipped through a possibly infected wound, Hamill said. In addition, there's the practical problem of IOL power calculation. "If you look at your patient and you think … an IOL [is needed], go ahead and do IOL calculations, but do it on the fellow eye, which is generally pretty close," Hamill said.

The surgical stage
To handle a traumatic cataract repair, the practitioner needs to include an assortment of special techniques. In doing a capsulotomy, it's critical to make sure that the practitioner can see the capsule, said Michael E. Snyder, MD, of the Cincinnati Eye Institute. "Typically, these cataracts may be white in many instances, and ICG [indocyanine green] or trypan blue can be extraordinarily helpful …," he said. This is, however, an off-label use of ICG and trypan blue; unfortunately trypan blue is not Food and Drug Administration-approved or available in the United States.

Any anterior capsular tears should be encompassed within the capsulorrhexis, Snyder said. How- ever, this is rarely possible. "The capsulorrhexis ideally should be complete and the desired size would be approximately 1 mm to 1.5 mm smaller than the desired IOL optic," Snyder said. "An intact capsulorrhexis is also mandatory for a capsular tension ring placement."

After the capsulorrhexis is complete, in cases of zonular dialysis, capsular retractors can aid in visualization of the lens and in its removal. Lens removal can be routine in cases where the posterior capsule is intact, however, not so when there's a tear. "When the capsule is compromised, vitreous could be admixed with the lens material," Snyder said.

The vitreous cutter should always be used whenever lens material is present within the vitreous material. Snyder recommends a pars plana approach. He finds that a viscotamponade can be very helpful in preventing vitreous prolapse when the hyaloid face is still intact but exposed to the anterior segment. "One should always start injecting the viscoelastic material over the area of exposed hyaloid face and then move the cannula distally as the chamber becomes more pressurized," Snyder said. When pulling the vitreous out of the anterior chamber, a pars plana approach is also ideal, Snyder said. "Trying to pull vitreous forward from a limbal incision is much less successful," he said.

Younger traumatic cataract patients may require special attention in lens removal. "The lens material may be very soft and may be aspirated in a dry fashion." In such cases, the anterior chamber can be filled with viscoelastic and the lens manually aspirated through a cannula.

In any traumatic cataract case, it may be necessary to deal with capsular plaques. These may occasionally need to be dissected from the capsular bag and can sometimes be very thick. Such plaques can be removed with both blunt dissection and viscodissection. "Once it's dissected, you can gently peel the plaque out," Snyder said.

However, occasionally these plaques can be attached to the posterior capsule by a stalk. "They can be lysed with a scissors," he said. "Then the entire plaque can be removed, leaving a clear posterior capsule and an intact bag."
When it comes to selecting the proper IOL for these patients, PMMA or acrylic are ideal, Snyder said. "I strongly discourage collamer or hydrogel implant," he said. "Also, no plate-haptic IOLs, silicone IOLs, or anterior chamber implants in these traumatic cases."

The implant should be placed within the bag, within the sulcus and sutured, or some combination of the two, he said.
"Traumatic cataracts truly are a mixed breed," Snyder said. "Successful surgery requires a wide variety of techniques and they must be suited to the particular occasion and particular case."

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