EyeWorld India September 2016 Issue

60 EWAP cornea September 2016 A wet lab demonstration of a limbal biopsy, which is part of the SLET procedure, performed on a goat eye Source: Ocular Surface Workshop III, Tej Kohli Cornea Institute, LV Prasad Eye Institute Surgeons at the Ocular Surface Workshop III perform live SLET surgery on a patient with limbal stem cell deficiency. Positive outlook for new technique to make LSCD treatment safer, cheaper, and more widespread Long-term data for simple limbal epithelial transplantation suggests it’s consistently safe and effective T he effects of limbal stem cell deficiency (LSCD) can be significant. Photographs of such cases show the conjunctiva growing over the iris and pupil, effectively blinding the person. Though this is one of the most extreme effects, pain and a lack of clarity are more common, among other symptoms. Treatment for this condition, which can result from traumatic injury, infection, or inflammatory conditions, began almost 3 decades ago with conjunctival limbal grafting. Then ex vivo cultivated limbal epithelial transplantation (CLET) became an additional treatment option about 10 years later. While conjunctival limbal grafting has its safety issues, CLET can be location and cost prohibitive, said Sayan Basu, MBBS, LV Prasad Eye Institute, Hyderabad, India. “If you think of conjunctival limbal grafting as a very radical procedure, where you take a lot of tissue, and if you think of ex vivo cultivated limbal epithelial transplantation as a complex procedure, the alternative to this is simple,” he said. Six years ago, Dr. Basu , Virender Sangwan, MBBS, LV Prasad Eye Institute, and their colleagues pioneered a new technique: simple limbal epithelial transplantation (SLET). This procedure involved transplanting the stem cells directly from patients’ healthy donor eye into their affected eye. 1 “What we do here is combine the advantages of the previous procedures. We take the same very small amount of tissue that is taken in [CLET] and instead of cultivating the stem cells in the lab,” which Dr. Basu said gets very expensive and limits the patient’s opportunity for treatments based on lab availability, “we cultivate it directly on the patient’s eye.” LSCD, regardless of its cause, is a potentially sight-threatening condition in which the cells responsible for replacing the corneal epithelium are lost or fail to function. Dr. Basu said a corneal transplant is not an option for these patients because the stem cells are not transferred in such a procedure—hence the need for a limbal stem cell transplant of some kind instead. Until recently, SLET was lacking in long-term safety, efficacy, and reproducibility data. Dr. Basu and his colleagues published a study in Ophthalmology earlier this year, detailing the clinical outcomes of SLET in 125 eyes (65 adults and 60 children) with LSCD resulting from ocular surface burns. 2 The minimum follow-up period was 1 year, with some patients being evaluated up to 4 years postop. The study found that 95 cases resulted in a successful outcome, and 67% of these cases had a best corrected visual acuity of 20/60 or better, which was a “significant improvement” compared to the patients’ baseline. The researchers did not observe any long-term negative effects in the opposite eye, which served to donate the stem cells. The most common complication, occurring in 23 of the 125 cases, was progressive conjunctivalization coming back even after SLET. Progressive symblepharon, hemorrhage under the human amniotic membrane, loss of the SLET transplant, keratitis, and corneal melting were other less common complications. The study also stated that success rates were similar for both by Liz Hillman EyeWorld Staff Writer