EyeWorld Asia-Pacific June 2024 Issue

CORNEA

surface improves, many of these eyes can recover quite well and subsequently, their vision improves.

Dr. Deng said that we want our trainees to be exposed to various procedures and therapies. “The fellows and residents are here to get exposed to how we make the diagnosis, stage the disease, using multimodal in vivo imaging. First, the fluorescein staining pattern is carefully examined to detect stippling staining in a whorl-like pattern, Next, an anterior segment optical coherence tomography is performed to detect whether a hyporeflective epithelial layer is present on the cornea and limbus. Lastly, in vivo confocal microscopy is performed to evaluate whether corneal and limbal epithelial cells are present in high density.” These in vivo imaging tests are a fast way to make the correct diagnosis of LSCD, she said. “We also perform impression cytology to confirm presence of conjunctival cells on the cornea, which is the hallmark of limbal stem cell deficiency,” Dr. Deng said. “The trainees are exposed to the surgical techniques of limbal stem cell transplantation and amniotic membrane graft for partial deficiency. Our trainees here have well rounded exposure to the diagnosis and management of limbal stem cell deficiency.” Dr. Deng stressed the importance of not jumping into limbal stem cell transplant for these patients before ensuring that you’ve made the correct diagnosis and staged the disease. “Without knowing whether the eye has limbal stem cell deficiency or at what degree of severity, the treatment selection might not be appropriate,” she said. “It’s very important that the disease is correctly diagnosed and staged so the appropriate treatment can be given to the patient with the least invasive way to treat this disease.” Marjan Farid, MD Dr. Farid has found the best approach for severe cases of LSCD to be ocular surface stem cell transplantation with systemic immunosuppression, and her practice at UC Irvine is a site that’s set up to perform these procedures and manage them postoperatively. Limbal stem cell deficiency occurs when the limbal stem cells of the ocular surface are diseased, Dr. Farid said. Patients might have mild early disease, she said, which can be caused by chronic contact lens wear resulting in chronic hypoxic damage to the limbal stem cells. “Those early stem cell deficiency patients, where part of their limbus is affected, some of these can be medically managed,” she said. This could include things like removing the offending agents from the ocular surface, using preservative free eye drops, and decreasing the inflammation of the ocular surface. Early disease can also be caused by chronic exposure to preservatives in drops, such as long-term use of glaucoma medications, Dr. Farid said.

The choice of treatment, Dr. Deng said, will depend on the stage of LSCD. If the patient does not recover by the optimization of the ocular surface—for example taking a holiday from contact lens use in LSCD induced by soft contact lens wear—Dr. Deng said she might proceed with a scleral lens, which can protect the cornea and can improve vision. “This is a really good device for eyes with severe dry eyes in addition to LSCD,” she said.

Dr. Deng said she has had success treating LSCD resulting from prior glaucoma surgeries with scleral lenses.

For more severe cases of LSCD, Dr. Deng will move to surgery.

She has performed the SLET procedure as the preferred option if the disease affects only one eye. Another option, she said, if the patient has bilateral severe disease, is to use the Boston KPro. “If they have contact lens intolerance or have a severe cornea scar that a contact lens wouldn’t improve their vision, then KPro would be a good option,” she said. Dr. Deng is also currently recruiting for a Phase 1 clinical trial investigating cultivated autologous limbal stem cells. If patients meet inclusion criteria, a tiny limbal tissue is removed from one eye, and the limbal stem cells are grown on a dish. Once there are enough stem cells, they are transplanted back to the diseased eye, she said. Dr. Deng also has experience and success with using allogeneic stem cell transplantation with systemic immunosuppression for these patients with severe bilateral disease. However, she noted that she doesn’t employ this option as often because of a lack of interest in her patient population. “Our patients are mostly elderly patients, and they are not very keen on immunosuppression,” she said. She noted that stem cell transplantation with immunosuppression is an option, adding that it has been shown to be safe by Dr. Holland and others. “I think it’s the patient’s selection and whether the center has the expertise to do that,” she said. “I collaborated with a team of renal transplant surgeons and internists to manage those patients. I have to congratulate Dr. Holland on their success because it’s very labor intensive, and it takes commitment on him, the renal transplant team, and the patient to manage the postoperative care and immunosuppression properly. It is a matter of disseminating the knowledge and protocol to other ophthalmologists so that they can adapt the protocol.”

Then, she said, you have patients who have very severe ocular surface disease and severe limbal stem cell

31

EyeWorld Asia Pacific | June 2024