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Experts Tackle Cataract Complications, Part 1
 
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At last November’s Spotlight Session, audience members voted on video case studies highlighting myriad clinical challenges, including IOL exchanges, traumatic cataracts, and surgery in patients with chronic uveitis. Here, the experts weigh in with additional perspectives.

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This past November, the 11th annual Spotlight on Cataract Surgery Session at the Academy’s Joint Meeting was entitled “Clinical Decision-Making With Cataract Complications: You Make the Call.” Cochaired by William J. Fishkind, MD, and myself, this four-hour symposium was organized around seven video cases that presented a range of cataract surgical challenges and complications.

The cases were selected from my own practice. As I presented the videos, I would pause at the point of a management decision or complication. The attendees were then asked to make clinical decisions using their electronic audience response keypads. This was followed by several rapid-fire didactic presentations on topics of relevance to the case. Next, a rotating panel of two discussants (who had never viewed the case) was asked to make a management recommendation before the video of the outcome was shown. Following additional audience polling about preferences and practices, the two panelists summarized their own opinions.

In all, nearly 40 presenters and panelists spoke about managing a refractive power surprise; unhappy multifocal patients; intraoperative floppy iris syndrome; mature white, brunescent, and traumatic cataracts; capsulorrhexis and posterior capsular tears; zonular weakness; and how to address pupil defects.

Jack T. Holladay, MD, concluded the symposium by delivering the Academy’s eighth annual Charles Kelman Lecture, titled “The Perfect IOL Calculation.” The entire symposium, including videos and PowerPoint, is available for purchase at www.aao.org/ondemand.

This EyeNet article reports the results of the 32 audience response questions, along with written commentary from symposium speakers and panelists. Because of the anonymous nature of this polling method, the audience opinions are always interesting.

The Academy’s meeting features a daylong, continuous series of cataract symposia that constitute Cataract Monday. In the afternoon, the ASCRS-cosponsored symposium (Femto Forum: Cataract, Cornea, Refractive, and Beyond) was followed by a special spotlight symposium on pseudoexfoliation.

—David F. Chang, MD  
Cataract Spotlight Program Cochairman  

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Case 1: IOL Power Surprises After LASIK

 
 

Q  In your experience, what is the single best method for determining the IOL power in post-myopic LASIK eyes?

Clinical history method

17.1%

Masket formula

5.9%

Haigis-L formula

29.6%

Topography extrapolations

19.7%

Intraoperative wavefront refraction

11.2%

No opinion

16.4%


Doug Koch
  It is interesting to see the disparity of responses. There is no one approach that is preferred by the audience. I think that this nicely reflects the complexity and ambiguity we face in doing these calculations. A formula may work well in one eye and then underperform, compared to other formulas, in the next eye.

This is the reason we created the ASCRS online calculator (http://iolcalc.org). While it enables clinicians to use the formula of their choice, it also provides an average value, which is sometimes the best approach of all. It also provides a printout that can be shown to the patient to underscore the range of lens powers from which the surgeon must choose.

Mark Packer  The somewhat diffuse audience response underlines a vast uncertainty about how to best deal with post-LASIK eyes. Incorporating intraoperative wavefront measurement into my approach has demonstrably improved the refractive outcome of IOL implantation in these cases. Pooled data from surgeons employing this technique verify these results. Employing the ASCRS calculator provides useful brackets for the IOL power; performing the aphakic refraction during surgery establishes the optimal choice. By utilizing this two-part method in my practice, I have been able to achieve 20/40 or better uncorrected acuity 100 percent of the time.

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Q  This unhappy 57-year-old patient is 10 years out from LASIK for myopia and five years out from having a Crystalens implanted in her left eye. The phakic right eye is –2.50. The left eye is –7.50 + 2.50 x 150, with a large myopic power surprise and a secondary membrane. How would you manage her?

Nd:YAG capsulotomy and prescribe glasses

16.0%

Nd:YAG capsulotomy—then piggyback IOL

12.7%

Piggyback IOL—then Nd:YAG capsulotomy

13.8%

IOL exchange with monofocal IOL

16.6%

IOL exchange with toric IOL

27.1%

Refer elsewhere

13.8%


Warren Hill
  I find it interesting that the most popular response was to opt for an IOL exchange in favor of a toric lens. It should be remembered that a toric IOL requires implantation completely within the capsular bag and long-term stable alignment. This portion of the audience may have never attempted to reopen the capsular bag five years after a Crystalens implantation. Those familiar with this IOL know that the distal portion of the haptics can be exceptionally difficult to mobilize, and they are frequently left in place following amputation. In my opinion, five years after the original surgery, this option is the least likely to have the potential for a successful outcome.

An IOL exchange in favor of a monofocal IOL has the advantage in that the capsular bag does not need to be completely reopened, and the exchange lens can be placed in the ciliary sulcus. For those comfortable with a potentially complex IOL exchange, this is a reasonable option.

With 3.75 D of anisometropia, glasses may be tolerated, but not by all, and a slab-off lens would be required to prevent diplopia in downgaze.

For a spherical equivalent of –6.25 D, I would not recommend myopic LASIK. Additional central corneal flattening would only increase an already elevated spherical aberration value. And if the ablation was in any way off center, such an approach would also add coma. In my opinion, this patient would be a poor candidate for additional refractive surgery.

Because a lens exchange would be challenging, and provided there is adequate space between the posterior iris and the anterior surface of the Crystalens, I would opt for the placement of a piggyback IOL followed by an Nd:YAG laser capsulotomy. For this scenario, the astigmatism could also be reduced, but not eliminated, by limbal relaxing incisions. For a minus-power piggyback IOL, when the spherical equivalent to be corrected is less than –7 D, the power change required at the spectacle plane is simply multiplied by 1.3 to give the power of the piggyback IOL. Three-piece, foldable, minus-power IOLs are available in a range that could be used for this purpose.

José Güell  It is impossible to properly correct this scenario at the corneal level; thus, an intraocular approach is much better and more appropriate. It is also more appropriate and safer to delay Nd:YAG capsulotomy until the refractive problem is solved. A toric piggyback IOL, such as the Sulcoflex, would be an option, but visual quality is always superior with one optic, so I would try an exchange.

Once the capsular bag has been viscodissected and reopened, if the haptics are very difficult to remove, they might be cut. Usually, however, with slow maneuvers, you can dissect and extract the IOL in one piece (or in several pieces) through a small incision, around 2 mm. Once the first IOL is extracted (complete or not), a toric in-the-bag IOL can be introduced, following your standard for proper orientation. Calculating the power, based on the power of the previous IOL, is quite simple in pseudophakic post-LASIK eyes.

In any circumstance in which you do not obtain an adequate dissection of the capsular bag, a spheric IOL should be implanted, leaving correction of the astigmatism (either with laser or incisional corneal surgery) for later.

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Q  During the IOL exchange attempt, one of the Crystalens haptics is found to be fibrosed within the capsular bag equator. What would you do now?

Use instruments to dissect the haptic free

0.0%

Viscodissect the haptic free

13.1%

Amputate the haptic

80.0%

Abort the IOL exchange and implant a piggyback IOL

1.3%

Would refer elsewhere

5.6%


Bonnie Henderson
  The most difficult parts of an IOL exchange are mobilizing and removing fibrosed haptics. These can be a challenge with any type of IOL, but the challenge is even bigger with the Crystalens, due to the design of the distal haptics. These haptics tend to fibrose into place sooner than those of traditional three- or single-piece IOLs. If the haptics are securely fibrosed, aggressive attempts to extract them should be curtailed to prevent zonular dialysis. Instead, the haptics can be truncated and left in place. The majority of the audience agreed with this approach.

However, this can sometimes be easier said than done. Care should be taken to avoid pulling on the IOL when attempting to amputate the haptic. It is easy to break zonules while positioning the scissors to cut the haptics. To prevent this from happening, cut the optic in half first. Then only half the IOL is being manipulated while you attempt to cut the haptic, thus avoiding the risk of pulling on the other haptic/bag junction 180 degrees away. An additional benefit of bisecting the optic is that it allows for the removal of the optic through a small incision. Lastly, it is important to have the right tools for the IOL exchange. Having microforceps and microscissors at hand is paramount when IOL manipulation is warranted. 

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Q  If you were a 60-year-old patient undergoing cataract surgery with a monofocal IOL, what would you elect if you had +1.00 D x 165 of astigmatism?

Manual astigmatic keratotomy

2.2%

Femtosecond laser astigmatic keratotomy

5.8%

Toric IOL

42.3%

Incision on axis

19.7%

Would not treat

29.9%


Stephen Lane
  Interestingly, roughly 25 percent of the audience would treat 1 D of against-the-rule (ATR) astigmatism with corneal incisional techniques, approximately 45 percent would use a toric IOL, and, remarkably, 30 percent would not treat it at all! I would be curious if these same audience members would not include the astigmatism component of a spectacle prescription.

Granted, ATR astigmatism will give some increased depth of focus and possibly aid in near vision. However, we have recently been reminded by Doug Koch that the posterior cornea possesses ATR cylinder, which may be as much as 0.5 to 0.75 D in addition to any measured anterior corneal cylinder.1 If I were undergoing cataract surgery today, I would certainly desire my cylinder fully corrected; in this case, full correction would be most predictably achieved (given the total of roughly 1.5 to 1.75 D) with a toric IOL.

When discussing cataract surgery, I believe it is in the best interest of our patients to include a thorough discussion of astigmatism correction—and to consider this discussion in the same light as we have always considered full astigmatic correction in our patients’ spectacles.

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1 Koch DD et al. J Cataract Refract Surg. 2012;38(12):2080-2087.

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Case 2: Unhappy Multifocal IOL Patient

 
 

Q  How long postoperatively are you generally willing to perform a multifocal IOL exchange?

Three months

11.2%

Four to six months

14.6%

One year

11.2%

No time limit

44.7%

Would refer

18.4%


Thomas Kohnen  In general, a multifocal IOL exchange can be performed at any time. However, the further you are from the primary implantation, the more complicated such an IOL exchange can be.

Before exchanging a multifocal IOL, I would try to detect any underlying problems. Dry eye is common, as are residual refractive errors. Both entities can be treated—with medication for dry eye or, in the case of refractive errors, with glasses, excimer laser surgery, or supplementary IOL implantation into the sulcus. With the treatment of these two complications, most of my patients have been able to tolerate multifocal IOLs, and an IOL exchange became unnecessary. Other potential complications include cystoid macular edema (CME) or low endothelial cell count, which also should be detected before implanting a multifocal IOL.

If one has a major concern about the acceptance of a multifocal IOL in a patient, I would recommend waiting before performing Nd:YAG laser capsulotomy because this will make IOL exchange more complicated and challenging. However, in some cases, the treatment of an opaque capsule (sometimes not even seen at the slit lamp) can tremendously improve the outcome after implantation of a multifocal IOL.

In summary, IOL exchange of a multifocal IOL is always possible; however, the later it occurs, the more complicated the exchange may be! On the other hand, all complications—such as dry eye, residual refractive errors, endothelial damage, or macular problems—should be detected and treated before an IOL exchange is even considered. With this strategy, in my experience, most patients can in general tolerate and enjoy multifocal IOLs.

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Q  This 73-year-old patient is four years out from a combined phaco-trabeculectomy procedure with bilateral ReStor IOLs. She has a long list of complaints, including poor spectacle-corrected acuity in her right eye, in which she has had an Nd:YAG capsulotomy. Both eyes have BCVA of 20/30, but the right eye has higher-order aberrations. What option would you offer her?

Reassurance and more time for adaptation

16.5%

Keratorefractive laser enhancement

46.8%

IOL exchange

19.0%

Referral to another ophthalmologist

15.2%

Referral to a psychiatrist

2.5%


Eric Donnenfeld  Managing the unhappy presbyopic IOL patient begins with evaluation of the five C’s: cornea and ocular surface, cylinder and refractive error, capsule opacification, CME and retinal issues, and centration of the IOL on the pupil.

In this case, assuming the ocular surface was healthy, a careful refraction would be in order, especially following a phaco-trabeculectomy, in which cylinder is often induced. Optical coherence tomography of the macula and optic nerve would also be in order to rule out macular pathology and optic nerve damage from the glaucoma. Despite the four-year history and the open posterior capsule, an IOL exchange would be in order, because the right eye has a BCVA of 20/30 with high-order aberrations and poor quality of vision.

I would replace the multifocal IOL with a three-piece monofocal IOL that optimizes the reduction of high-order aberrations. Finally, I would not consider treating the left eye until the right one was stable. Often, unhappy patients with multifocal IOLs do extremely well with a monofocal IOL in their dominant eye while maintaining the multifocal IOL in their nondominant eye.

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Q  During attempted IOL exchange, one of the ReStor haptics is found to be fibrosed within the capsular bag equator. What would you do now?

Use instruments to dissect the haptic free

5.3%

Viscodissect the haptic free

10.3%

Amputate the haptic

73.4%

Abort the IOL exchange and implant a piggyback IOL

6.4%

Would refer elsewhere

4.6%


Kerry Solomon  It is not uncommon for the peripheral terminal bulb of a ReStor lens to become fibrosed within the capsular bag. This can occur early or later in the postoperative time period. Surgeons should be aware of this potential issue and avoid stressing the capsular bag or the zonular supporting system. Careful attention can often avoid a zonular dehiscence or a capsular tear.

When a surgeon finds one or both of the ReStor haptics to be fibrosed in the capsular bag, the majority of the attendees in the audience (73 percent) would elect to amputate the haptic. This is certainly a reasonable strategy and one that permits a new lens to be reinserted into the capsular bag. The haptics of the new lens should be oriented 90 degrees away from an amputated haptic to permit the lens to center properly and for the new haptics to rest in the capsular equator.

Another successful strategy is to viscodissect the fibrosed haptic(s) free. I have found that the dispersive viscoelastic Viscoat works quite well for this purpose. The key is the positioning of the Viscoat cannula. Even in the presence of an apparently successful capsular expansion using Viscoat, the peripheral haptic(s) can still be persistently fibrosed. In my experience, performing a viscodissection directly down the peripheral haptic will often free the terminal bulb from its encased fibrotic complex. This permits complete removal of the ReStor lens.

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Q  Do you have personal experience with explanting presbyopia-correcting IOLs?

Yes—but only multifocal IOLs

15.1%

Yes—but only accommodating IOLs

3.6%

Yes—both multifocal and accommodating IOLs

8.3%

I use them, but have never explanted one

36.1%

I don’t use these IOLs

36.9%


Rich Tipperman  It is not surprising that the majority of surgeons (73 percent) have not explanted a presbyopia-correcting IOL, as this is still an uncommon procedure. Nonetheless, despite the best available technologies, preoperative evaluations, and efforts on behalf of both the patient and the surgeon, there will be rare patients who are dissatisfied enough with their visual function from a presbyopic IOL that they will require exchange for a monofocal IOL. In the hands of an experienced surgeon, this procedure is remarkably safe and effective and will typically provide complete resolution of any visual symptomatology the patient was experiencing referable to the presbyopic IOL.

Of course, no surgeon would ever want to create a scenario in which he or she has to perform an IOL exchange. But the procedure should be seen for what it is clinically: a way to make the refractive component of presbyopic IOL surgery 100 percent reversible. When viewed in this fashion, the ability to reverse the refractive effect becomes a positive feature rather than a negative one. Not even laser vision correction enjoys this 100 percent reversibility.

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