Abstract
Purpose:
Severe ocular burns can destroy the corneal epithelial stem cells at the limbus resulting in a blinding disease called limbal stem cell deficiency (LSCD). This study describes the long-term outcomes of a relatively new technique of treating LSCD called Simple Limbal Epithelial Transplantation (SLET).
Methods:
This retrospective case series included 125 eyes of 60 children and 65 adults who underwent SLET for treatment of unilateral total (n=107) or focal (n=18) LSCD between 2010 and 2013. The surgical technique of SLET involved obtaining a one-clock-hour sized limbal biopsy from the healthy eye, dividing it into smaller pieces and then transplanting them directly onto the affected eye over a human amniotic membrane graft. The primary outcome measure was the rate of successful transplantation, defined clinically and by using high-resolution optical coherence tomography imaging, as a completely epithelized and avascular corneal surface. Secondary outcome measures were improvement in best-corrected visual acuity (BCVA), incidence of complications and immunohistochemical analysis of the transplanted epithelium.
Results:
The median post-operative follow-up was 1.5 years (range: 1 to 4 years). Kaplan-Meier survival analysis showed an overall success rate of 76% at 1-year and beyond. Successful transplantation was maintained until final follow-up in 72% of children and 80% of adults; and in 75% and 83% of cases of total and focal LSCD, respectively. Multivariate analysis revealed that presence of symblepharon (P<0.0001, OR=11.6), combining SLET with keratoplasty (P=0.007, OR=8.1) and evidence of calcification on histopathology (P=0.003, OR=4.7) were significant high-risk factors of SLET failure. BCVA improved from 20/200 or worse in all eyes to 20/60 or better in 60% of successful cases. No adverse effects were noted in the donor fellow eyes. Immunohistochemistry of post-SLET corneas excised during keratoplasty showed presence of uniform stratified squamous epithelium expressing cornea-specific markers (CK3/12) and absence of conjunctival marker (Muc5AC).
Conclusions:
Autologous SLET effectively restores the normal corneal surface and improves vision in cases with blinding unilateral corneal burns. SLET is also a safe and affordable alternative to existing techniques of limbal stem cell therapy for corneal burns as it requires minimal donor tissue without laboratory cultivation,