COMMENTARY

Cataract Surgery: Challenges and Complications

American Academy of Ophthalmology (AAO) 2014

Roger F. Steinert, MD

Disclosures

November 21, 2014

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"Cataract Monday"

Hello. I am Dr Roger Steinert, chair of ophthalmology and director of the Gavin Herbert Eye Institute at the University of California, Irvine. Today I will summarize the sessions dedicated to cataract at the American Academy of Ophthalmology (AAO) meeting. The "Cataract Monday" sessions have become a highlight for any cataract surgeon who attends the AAO meeting.

It started with a 4-hour session, co-moderated by Bill Fishkind and David Chang, on the various challenges in cataract surgery. The format uses clinical cases that illustrate these challenges, followed by a series of short (3- to 5-minute) talks related to the general subject of cataracts but not necessarily specific to the case. After this is a panel discussion about the preceding talks and the management of the case. Audience response questions engage the audience and measure the impact of the material that has been presented, to see whether it has influenced audience members' opinions; sometimes it does and sometimes it doesn't.

In the afternoon, a 2-hour structured symposium by the American Society of Cataract and Refractive Surgery was held. This year, the session was co-moderated by Ed Holland and Steve Lane, and the panelists were Eric Donnenfeld, Tom Samuelson, and myself. We had a series of presentations covering the entire range of complications and challenges in cataract surgery, with a 3-minute discussion after each 7-minute didactic presentation.

The Ongoing Challenge of Astigmatism

A topic that still generates intense interest is toric intraocular lenses (IOLs), because astigmatism continues to pose challenges. We are all increasingly appreciative of the impact of uncorrected astigmatism on patients' quality of life. We want to minimize postoperative astigmatism in the best possible way and manage the issues and complications associated with the lenses and/or the astigmatic incisions. There was much discussion about how to deal with posterior corneal astigmatism, an issue that was raised by Doug Koch several years ago and continues to generate significant interest.

I would like to focus on one aspect of astigmatism. How do you get accurate preoperative measurements to drive your decision-making? Warren Hill gave a very nice presentation that included analogies to the multiple instruments used in flying an airplane, because sometimes an instrument can fail or one of the instruments gives a different reading from the other instruments. He used that analogy in talking about a situation in which astigmatism measurements don't line up and how you decide what to do. Redundancy was the theme of his talk.

In the case of astigmatism, you have several choices. You have the automated keratometry readings from the IOLMaster (Carl Zeiss; Richmond, Virginia) or LENSTAR (Haag-Streit AG; Koeniz, Switzerland), which are the most commonly used preoperative measuring devices. You have the sim-k [simulated keratometry] readings from corneal topography. You have the corneal topography map itself that you "eyeball." And, finally, you have manual keratometry with one of the various devices; some ophthalmologists do this routinely, and others do it only when there is a disparity among the other readings (which is my practice). I have two of the old Haag-Streit Javal keratometers in the office, and if I find a significant disparity between the automated readings and the topography, those are my go-to instruments for a tie-breaker.

Dr Hill emphasized repeatedly how important it is to look at that carefully and make sure that your readings make sense, and if there is a disparity, to try to get to the root of it. It could be something as simple as dryness causing an artifact in the surface or it could be something much more profound—even a previously unrecognized low-level forme fruste keratoconus, which nevertheless could have a real impact on the quality of vision with an IOL.

How Smartphone Apps Can Help

We expanded on that theme in the talks that followed Dr Hill's presentation. I spoke about dealing with complications from toric IOLs, the first being: How do you figure out where the lens is?

I recommended the very simple method of using one of the available smartphone apps that function as leveling tools, which I have talked about in previous blogs, and although it's designed as a carpenter's leveling tool, the iHandy app is easily used for ophthalmology. The other app is designed for ophthalmology and is called Access Assistant. That app can also be used for marking the length of an astigmatic keratotomy or limbal relaxing incision, so it is quite versatile. You use the slit beam, oriented along the direction of the implanted toric IOL, and then pull back and put that on the edge of the smartphone with the level display activated, and you will see the exact orientation of the toric lens.

Once you determine where it is, you have to figure out where you are going to put it. You can put it on the postoperative residual steep K, which will have been influenced by your cataract incision. The other method is to use the Berdahl & Hardten toric IOL calculator, which you can get online at Astigmatismfix.com; it lets you download the app at no charge. The calculator uses refraction, so it takes into account your posterior corneal astigmatism. And because it is a pseudophakic rather than a phakic patient, refraction is quite accurate and not influenced by any cataract. In the postop situation, refractive information is quite helpful. You plug that in and it will do an automated vector analysis and show you the position of minimum astigmatism, and tell you how much residual astigmatism to expect in case an IOL exchange rather than an IOL rotation is done.

Getting and Keeping the IOL in Place

Finally, once you know where you want to put the lens, you have to position it. Fortunately, this can be done through small side-port incisions, and if the patient is within a few weeks post-op, you can rotate the lens quite easily with a little viscoelastic to open up the minimally sealed space between the anterior and posterior capsule, and then rotate the lens into position.

Sometimes the lens will not stay where you put it, even the second time around. The options in that case are to put in a capsule tension ring or keep the haptics in the capsule bag, because in the United States, these are all single-piece lenses designed for capsular fixation. It is dangerous to have the haptics in the sulcus with the one-piece acrylic lenses. The Trulign lens (Bausch & Lomb; Rochester, New York) is designed only for capsular fixation. In the case of the one-piece acrylic lenses from Abbott Medical Optics (Santa Ana, California) and Alcon Laboratories (Ft. Worth, Texas), you can bring the optic anterior and capture it in the capsulorrhexis, assuming that the rhexis is smaller than 6 mm, and that will absolutely fix the lens in place. But if you do that, you need to have assessed preoperatively whether there is enough space between the iris and the anterior capsule, so that this can be done safely without risking iris chafe, pigment dispersion, or inflammation.

The alternative that has been touted as working well (although I have not seen any series large enough to show whether this is accurate) is to use the capsule tension ring. You put in a capsule tension ring after the IOL is in position and that hopefully pins the peripheral haptics into position and keeps them stable.

These are some thoughts on astigmatism and toric lenses. I hope you find this interesting.

I'm Roger Steinert. On behalf of Medscape, thank you very much for viewing.

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