I congratulate Basu and associates for their recently published study of ocular surface reconstruction in cases of corneal disease and limbal stem cell deficiency (LSCD). In particular, I appreciated the histopathologic analysis that the authors performed on the corneal buttons obtained during penetrating keratoplasty (PK). Specifically, the examination showed a normal epithelium when the limbal stem cell transplant had been performed previously, confirming once again the effectiveness of this procedure.
Above all, the analysis described the extent of corneal involvement after corneal burns. I would like to emphasize that the endothelium–Descemet membrane complex was normal in all cases. Although it is known that the immunogenicity of the transplanted corneal tissue is mainly the result of the epithelium, endothelial rejection can occur as a result of host immunologic recognition. In the presented series, the endothelial rejection caused the failure of corneal transplants (PK) in 73.7% of cases (14/19 eyes) and proved to be independent from the timing of PK (11/14 with a 2-stage procedure vs 3/14 with a single-stage procedure).
In contrast to PK, deep anterior lamellar keratoplasty (DALK) is able to provide comparable or better visual results when the inner corneal layers are not affected by pathologic features, as in lattice degeneration and keratoconus. Moreover, endothelial rejection does not occur. This is certainly because of the absence of contact between aqueous and donor tissue, which results in a less pronounced immunologic reaction. All these considerations lead to the same appeal: save the endothelium whenever possible!
I note that the authors used PK until February 2010 in cases of ocular surface reconstruction, and I am interested to know whether their surgical approach has changed recently.
Second, a major point of criticism concerns the lack of immunochemical confirmation of the diagnosis of LSCD. In fact, the clinical usefulness of the identification of cytokeratins 3 and 19 has been tested previously. In addition, the differentiation of the severity of LSCD, as suggested by Colabelli Gisoldi and associates, was not performed. In light of this, although agreeing with the recommendation of the authors to perform the reconstruction in 2 stages, I would like to point out that the study may have biases, and therefore may not have sufficient scientific rigor to provide specific recommendations in this regard.
Finally, I also would like to point out that the tables show some inconsistencies in the number of cases with different types of burns. In addition, there was also at least one case of partial LSCD, Although the authors claimed to study “PK for unilateral total LSCD.”