Eyeworld

EW FEATURE 58 by Lauren Lipuma EyeWorld Staff Writer Experts discuss the practices they use to manage cataracts in the presence of corneal disease C oexisting corneal diseases such as keratoconus or corneal scarring add a layer of complexity to treating typical cataract patients. Christopher Rapuano, MD, Wills Eye Hospital, Philadelphia; William Trattler, MD, Center for Excellence in Eye Care, Miami; and Mitch Weikert, MD, Cullen Eye Institute, Baylor College of Medicine, Hous- ton, discussed the biggest challenges they face in treating patients with cataract and corneal comorbidities and current techniques for opti- mizing visual outcomes in these patients. Managing a corneal scar Although corneal transplantation is generally successful, surgeons usually try to avoid it if at all possi- ble, said Dr. Weikert, so smoothing or clearing the scar before cataract surgery is a good idea. Identifying the scar's impact on the shape of the cornea, as well as its degree of opacification, are keys for deciding how to proceed, he said. "If you can reestablish a smoother cornea surface but still have some opacity left over, often that'll improve vision enough so that you may avoid a transplant procedure," Dr. Weikert said. Superficial keratectomy and excimer laser PTK are viable options for clearing the cornea prior to cataract surgery, said Dr. Rapuano. He feels it is better to perform these procedures before removing the cat- aract because you can easily correct for changes in the corneal curvature with the IOL power calculation. If the cornea remains cloudy, Dr. Rapuano recommends being extra cautious during the cataract surgery—using an external light source, enlarging the pupil, or using capsular staining techniques to get a better view. Operating on a keratoconus eye "Surgically, keratoconus corneas tend to be thinner and floppier, and the clear corneal wound tends to leak, so those patients often get a suture or two when your standard cataract patient would not," said Dr. Rapuano. Dr. Weikert sutures his kerato- conus patients as well and will still do a clear corneal incision as long as there is not significant thinning at the periphery. In that case, he will perform a scleral tunnel. In contrast, Dr. Trattler does not routinely use sutures when the incision is placed at the temporal limbus. "I haven't felt that the peripheral cornea is always floppy and in need of a suture," he said. "But I check the wound integrity, and then I either use a suture or ReSure Sealant [Ocular Therapeutix, Bedford, Mass.]." Femtosecond cataract surgery can be used on patients with kerato- conus as long as the cornea is clear, Dr. Trattler added. "I use the LENSAR [Orlando, Fla.], which has a liquid interface, so it can image an eye with keratoconus easily, and then can treat the cataract very success- fully," he said. Corneal collagen crosslinking is a good option for strengthening and stabilizing the cornea prior to cataract surgery in cases of pro- gressive keratoconus or ectasia, the physicians said. Dr. Trattler recommends crosslinking before surgery only when the cataract is mild; for more significant cataracts, he recommends performing crosslinking after cata- ract surgery. "If the cataract is pretty significant, it doesn't make sense to wait because the reshaping of the cornea is a slow process that can take a couple of years," he said. "Cataract surgery can make an immediate impact on patients' qual- ity of vision if they have a visually significant cataract and keratoconus without a significant central corneal opacity," Dr. Trattler said. "Taking care of the cataract first makes the most sense in my opinion." Order of procedures If a patient's scar or keratoconus re- quires a corneal transplant, treating the cornea first, the cataract first, or doing a combined triple procedure each have advantages and disadvan- tages. Dr. Rapuano will operate on the factor that most affects vision first, and if they have equal contributions, he will do a triple procedure. Dr. Weikert thinks that in the long term, treating the cornea first provides better visual results. "A large element in choosing the IOL for cataract surgery is the corneal power," he said. "So I try, if at all possible, to do the cornea first and then follow up with the cataract later." Phaco and corneal comorbidities September 2014 AT A GLANCE • An important impact of corneal comorbidities is on the IOL power calculation. • Toric IOLs are not recommended in many of these cases. • Operating on the cornea first, cataract first, or doing a triple procedure is the surgeon's choice, depending on the severity of corneal disease and cataract. Managing cataract patients with coexisting keratoconus or corneal scarring Dr. Trattler will typically offer cataract surgery as the primary treat- ment and then use crosslinking and scleral contact lenses as secondary treatments to improve vision quality in cases of keratoconus. "I do not perform a combined transplant or lamellar procedure for patients with a clear cornea because the technology we have now to help these patients see well is pretty solid," he said. If a corneal transplant is done first, the main challenge during cat- aract surgery is to protect the graft endothelium. Dr. Weikert uses the soft shell technique, with a disper- sive viscoelastic to coat the endo- thelium and a cohesive viscoelastic to deepen the anterior chamber and flatten the lens capsule. Dr. Rapuano recommends op- erating as peripherally as possible, either making the incision at the limbus or doing a scleral tunnel. In some cases, using the femtosecond laser may be a good idea if it can reduce phaco energy and therefore reduce stress on the endothelium, he said, but this is dependent on the patient and the graft. Triple procedures, on the other hand, do not expose the donor endothelium to the stress of cataract surgery, which can be an advantage if other anterior chamber abnormal- ities are present, said Dr. Weikert. The challenge, however, is that since they are typically done open sky, the eye is more prone to the effects of posterior pressure. "If you're doing it open sky, anything you can do preoperatively or intraoperatively to reduce pos- terior pressure is extremely import- ant," said Dr. Rapuano. "So I'll use Intacs corneal implant with haze central to the implant in eye with epithelial defect Source: William Trattler, MD Slit lamp image of an eye with keratoconus with significant central thinning and mild scarring. A Fleisher ring can be seen. Source: Christopher J. Rapuano, MD

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