This article is from January 2012 and may contain outdated material.
Fuchs endothelial corneal dystrophy (FECD) is a progressive disease in which patients develop corneal guttae, endothelial cell loss and stromal edema that worsen over time. In the past, severe FECD was generally treated with full-thickness penetrating keratoplasty (PK). However, technical progress over the last 10 years in Descemet stripping automated endothelial keratoplasty (DSAEK) has made this procedure a viable alternative to PK, offering shorter healing and vision restoration time, fewer complications and more predictable visual outcomes. DSAEK is now the most commonly used technique for endothelial keratoplasty.1
Patients with FECD are at risk for developing cataract as their corneal disease worsens. Thus, in considering surgery, the ophthalmologist should assess how much each condition contributes to the patient’s reduced vision. Does the patient need corneal surgery, cataract surgery or both? And if the answer is “both,” what is the best treatment approach: a staged procedure of cataract removal with IOL implantation followed later by DSAEK or a triple procedure that combines all three steps?
“The question of whether to do a staged or triple simultaneous procedure for patients with FECD and cataracts sparks a lively debate within the ophthalmology community,” said Steven I. Rosenfeld, MD, a cornea specialist at Delray Eye Associates in Delray Beach, Fla., and voluntary clinical professor of ophthalmology at the Bascom Palmer Eye Institute. “There has never really been a head-to-head study comparing the two approaches. So we don’t have a lot of strong data either way,” Dr. Rosenfeld said.
Factors to Consider in Treatment
When is corneal surgery needed? The type and severity of the patient’s symptoms can help guide the decision. Patients with FECD often have diurnal visual fluctuations: Because corneal edema worsens during sleep, the patient may awake with blurred vision each morning, which becomes clearer as the day progresses. It may take several hours for vision to improve.2
Glare can also be a problem for FECD patients as a result of confluent guttae, even when the disease is not advanced and no stromal or epithelial edema is evident. Such glare may be present with or without cataract.
If a patient complains of poor vision, and the cornea shows signs of edema and dense guttae, corneal transplant surgery should be performed, said Mark S. Gorovoy, MD, of Gorovoy MD Eye Specialists in Fort Meyers, Fla.
Adding cataract surgery. But if the patient has very severe FECD—without apparent cataract—the question of whether to perform cataract surgery as well is an important one. “There is a risk that if you do a corneal transplant and it causes a cataract, then you have to go back months or even a year later to perform cataract surgery; and that can damage the graft,” Dr. Gorovoy said. “So we usually address both the lens and the cornea in either a staged or simultaneous procedure.”
Age and chamber depth matter. But there are exceptions to this rule, Dr. Gorovoy noted. In a patient who is younger than age 40 with a deep anterior chamber (greater than 3 mm) and no cataract, the best choice is often to simply treat the corneal disease. “We know that some of these patients will eventually develop cataracts, but there is a good chance we can avoid cataract surgery for many years,” he said.
Patients who are older than age 40 and have a shallow anterior chamber are much more likely to develop a cataract—even if they currently have a clear lens—in the near term after corneal surgery. Thus, these patients are often good candidates for both cataract surgery and corneal transplants, said Dr. Gorovoy.
Staged or Simultaneous?
Pro staged surgery. Some clinicians say that the benefits of staged procedures include decreased potential for intraoperative complications. According to Dr. Gorovoy, when the cataract surgery is performed four weeks before the DSAEK, rather than at the same time, the position of the IOL is far more stable in the capsular bag. In addition, during the DSAEK phase of a staged procedure, the surgeon doesn’t have to deal with the influx of fluid that would occur during phacoemulsification. Performing the DSAEK alone allows for lower vitreous pressure, making it easier to insert and unfold the graft. Maintaining better control of the graft during insertion also helps reduce the risk of contact between the IOL and the graft endothelium and, accordingly, the risk of iatrogenic primary graft failure, Dr. Gorovoy said.
Moreover, said Dr. Rosenfeld, in a staged procedure, “If there’s a complication during cataract surgery alone, you just handle it then. And you have the luxury of coming back several months after the eye has quieted down, when it’s easier and safer to do a DSAEK. But if an intraoperative complication occurs in the cataract surgery step of a triple procedure, the overall procedure becomes longer and more difficult, and it’s harder to do the DSAEK afterward.”
Pro simultaneous procedures. On the other hand, W. Barry Lee, MD, partner in the cornea, external disease and refractive surgery service of the Eye Consultants of Atlanta, said that if the FECD is severe enough to warrant surgery, it makes sense to do the DSAEK and cataract surgeries together, since the patient is likely to need both procedures in the near term. “Having a simultaneous procedure accomplishes the goal of fixing both the cataracts and FECD with the same surgery. By doing them together, you don’t really add much to the complexity of the surgery or the risk of the procedure. And patients get their vision back more rapidly. We’ve looked at our results in staged versus combined procedures, and we have not found any increase in complications with the triple simultaneous procedures.”
Dr. Rosenfeld added that, with the patient undergoing surgery only once, a triple procedure reduces the risk of infection that comes with eye surgery as well as potential complications associated with anesthesia. It’s also more convenient for patients who travel long distances for surgery to have the procedures done simultaneously, he said.
Clinical Pearls for Cataract Surgery in FECD
IOL selection. Standard monofocal, aspheric IOLs are best because DSAEK introduces negative asphericity, and there may be degradation of visual acuity and reduced contrast sensitivity from a multifocal IOL and the overlying DSAEK tissue, said Dr. Gorovoy. He also recommended that surgeons be cautious about using toric or accommodative lenses, which require 20/20 visual acuity for best results.
Remember the hyperopic shift. After DSAEK, patients with FECD experience a hyperopic refractive shift, regardless of whether they have staged or combined surgery. Thus, in selecting the IOL power for a patient with Fuchs, the surgeon should aim for around –1.25 D of myopia to compensate.
Get a clear view. If you can’t get a good view during cataract surgery in a patient with FECD because of microcystic corneal edema, you can use a #69 Beaver blade to scrape off the epithelium in the center of the cornea. Often, this technique will clear the surgeon’s view enough to complete capsulotomy and phacoemulsification.1
Dyes can help. To improve visualization of the capsule, use a capsule-staining dye such as trypan blue. The dye will also stain the Descemet membrane, making it easier to see during descemetorrhexis, Dr. Lee said.
Size of capsulorrhexis. Aim for a capsulorrhexis that’s slightly smaller than the diameter of the IOL optic to allow for overlap of the anterior capsulorrhexis edge over the entire optic. This step minimizes the chance of lens dislocation during the DSAEK surgery that follows, according to Dr. Lee.
Large optic, small pupil. Using a larger-diameter IOL optic and constricting the pupil with miotics after implanting the IOL also allows for the insertion of a corneal graft in a more stable anterior chamber, without increased risk for endothelial cell loss.2
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1 Terry MA et al. Ophthalmology. 2009;116(4):631-639.
2 Eghari AO et al. Curr Opin Ophthalmol. 2010;21(1):15-19.
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What Do the Data Show?
There have been no randomized clinical trials or retrospective studies comparing outcomes in Fuchs patients who received staged procedures of cataract surgery followed by DSAEK versus simultaneous surgeries.
Results of a case series. However, some researchers have looked at complications and clinical results of combined procedures in case series. In a prospective, noncomparative interventional case series published in 2009, Terry and colleagues analyzed the outcomes in 315 eyes with Fuchs; of these, 90 had DSAEK alone, and 225 had triple procedures combining DSAEK, cataract removal and IOL implantation. 3 There were four graft dislocations in the 90 DSAEK-alone cases and four in the 225 triple-procedure cases. No patients in either group experienced iatrogenic primary graft failure. At six months after DSAEK alone, 90 percent of eyes had 20/40 best spectacle-corrected VA (BSCVA); and at 12 months, 100 percent had achieved that level. In the triple-procedure eyes, the percentages at the respective time points were 93 percent and 97 percent; there were no statistically significant differences in BSCVA between the DSAEK and triple-procedure groups. Mean cell loss in donor tissue in eyes assessed 12 months after surgery was 32 percent of endothelial cell density compared with preoperative levels (p < 0.001); there were no significant differences between treatment groups.
The researchers concluded that the triple procedure of DSAEK combined with cataract surgery provides rapid visual recovery with few additional risks.
Hopes for the Future
Dr. Rosenfeld believes that, in the future, we are likely to see a greater understanding of the genetics that underlie FECD. Such knowledge could contribute to more informed decision making, such that surgical procedures may become better tailored to individual patient characteristics.
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1 Lee WB et al. Ophthalmology. 2009;116(9):1818-1830.
2 Eghari AO et al. Curr Opin Ophthalmol. 2010;21(1):15-19.
3 Terry MA et al. Ophthalmology. 2009;116(4):631-639.
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Dr. Lee is on the speakers bureau for Allergan and Bausch + Lomb. Dr. Gorovoy reports no related financial disclosures. Dr. Rosenfeld is a lecturer for Allergan and a consultant to Inspire.