Eyeworld

EW FEATURE 38 AT A GLANCE • A stepwise approach to severe oc- ular surface disease and associated limbal stem cell deficiency may be helpful, beginning with optimizing severe dry eye. • To treat pseudophakic bullous keratopathy, Dr. Agarwal advo- cates using the combination of a glued IOL, a single-pass four-throw pupilloplasty, and pre-Descemet's endothelial keratoplasty (PDEK). by Ellen Stodola EyeWorld Senior Staff Writer and Digital Editor S ometimes surgeons face particularly challeng- ing cases where specific technology or techniques need to be utilized. Amar Agarwal, MD, Chennai, India, and Clara Chan, MD, Toronto, Canada, discussed how they tackle some of their challenging cornea cases. Severe ocular surface disease and associated limbal stem cell deficiency Dr. Chan finds the most challeng- ing patients she encounters are those with severe ocular surface disease and associated limbal stem cell deficiency. She said patients with Stevens-Johnson syndrome, graft-versus-host disease, and ocular cicatricial pemphigoid are particu- larly difficult. "These are patients who cannot be cured with a simple DMEK," she said. Dr. Chan said what makes these cases particularly challenging is that "there is no magic bullet cure." The medical therapies to optimize the ocular surface and severe dry eye are often not covered by insurance, and often the patients are lower income or on long-term disability and unable to afford many of the treatments. "Surgical options like a stem cell transplant or a keratopros- thesis for these patients are high risk, and the prognosis is often very guarded even in the best cases," she said. "Even on maximal treatment, patients are still symptomatic with varying degrees of dry eye, decreased vision, and eye pain." Dr. Chan said that there's also a high proportion of monocular patients with these ocular diagnoses, so there's addition- al pressure on the physician. Dr. Chan has several steps for managing these cases, and she pointed out that rehabilitation can take months to years. She advocat- ed a step-wise approach. First, she stressed the importance of optimi- zation of patients' severe dry eye. Next, she said to do oculoplastics repair of any eyelid deformities, lagophthalmos, or lash trauma issues. Physicians should do glauco- ma management via a tube shunt or cyclophotocoagulation since glau- coma drops are toxic to the already compromised ocular surface. The last step is surgical intervention to rehabilitate their corneal blindness. "In a young patient with no general health issues, a stem cell transplant with systemic immu- nosuppression would be my first choice, [but] in an older patient with multiple medical comorbidi- ties, a Boston type 1 keratoprosthe- sis would be my first choice," Dr. Chan said. Dr. Chan added that collabo- rating with good optometrists with expertise in fitting modern scleral lenses has helped these patients immensely and allowed some to defer surgery. "Collaborating with a medical transplant team of specialists has also helped me to successfully perform ocular surface stem cell transplants to rehabilitate those with severe limbal stem cell deficiency," she said. "Those un- dergoing stem cell transplants from a cadaver donor or a living donor require systemic immunosuppres- sion and monitoring for potential side effects. Having the assistance of a medical transplant internist allows me to focus on the ocular surgery aspects of the patient's care." Dr. Chan noted that the titani- um backplate KPro has been shown in studies to have a lower rate of corneal melt, which is helpful in patients with a poor ocular surface who are at high risk for melt. She also mentioned new treat- ments that could help such patients. In cases of acute Stevens-Johnson syndrome, amniotic membrane should be placed across the lids, fornices, conjunctiva, and corneal surfaces along with a symbleph- aron ring in the acute phase of the disease as this can prevent much of the late stage sequelae that is such a challenge to manage later on, Dr. Chan said. "There are a variety of novel keratoprostheses in devel- opment across the world that may have fewer complications," she said. Additionally, cultivated limbal stem cell therapy is expensive and challenging to replicate, but she thinks this technology will be better utilized in the near future. Pseudophakic bullous keratopathy According to Dr. Agarwal, some of the toughest cases to handle are those with pseudophakic bullous keratopathy with a bad cornea. He deals with this frequently and uses a specific management technique. The reason this is hard to treat is because once a complication has occurred during cataract surgery, there is a vicious cycle of vitreous prolapse. Corneal decompensation, once started, becomes a nightmare, Dr. Agarwal said. The issue then is that the patient's vision decreases, but a bigger problem stems from the corneal decompensation, which cre- ates discomfort, and finally scarring of the cornea starts. "Visualization for the surgeon is also badly affected," Dr. Agarwal said. "The problem in handling these cases is that we have to do multiple procedures at one time." The IOL has to be fixed, vitrectomy done, and the cornea replaced. Dr. Agarwal's technique is to do a glued IOL, a single-pass four-throw pupilloplasty, and pre-Descemet's endothelial keratoplasty (PDEK). For the glued IOL, Dr. Agarwal said the first step is to check the IOL. The patient may be aphakic or the IOL decentered or an AC IOL implanted. If it is an AC IOL that should be explanted and if a three-piece IOL is subluxated in the eye, the same IOL can be refixed with the glued IOL technique. This has now compartmentalized the eye into the anterior and posterior segment. If the existing IOL is in a good position, it can be left behind. The second part of his manage- ment strategy is to do a single-pass four-throw pupilloplasty. The idea here is a closed angle secondary glaucoma that gets corrected as the Dealing with challenging cases in corneal surgery Challenging cases • July 2018 Pseudophakic bullous keratopathy managed with the triple procedure of glued IOL, single-pass four-throw pupilloplasty, and PDEK. The left photo is preop and the right is 45 days postop. Source: Amar Agarwal, MD

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