We thank Dr Carifi for his interest in and observations on our article on the clinical outcomes of penetrating keratoplasty (PK) after autologous cultivated limbal epithelial transplantation for chronic ocular burns. In his correspondence, Dr Carifi questions whether, based on the histopathologic results of the corneal buttons obtained after PK that showed an intact endothelium, deep anterior lamellar keratoplasty (DALK) can be an alternative to PK in such cases? The obvious answer is yes. A more clinically relevant question would be: will DALK instead of PK result in better clinical results and longer corneal allograft survival? Only a comparative study between the 2 techniques can answer this question. Although we have performed DALK in a significant number of cases, this correspondence provides us with limited scope to compare meaningfully the results of PK and DALK after cultivated limbal epithelial transplantation for limbal stem cell deficiency (LSCD).
The second question regarding the lack of impression cytologic and immunochemical data for the diagnosis of LSCD is even more theoretical. The sensitivity, specificity, and predictive values of such analyses are unknown. Routinely, ocular surface surgeons all over the globe make therapeutic decisions based exclusively on clinical signs, without any laboratory tests, which can, at most, be considered supplementary to a clinical diagnosis. Ironically, in the clinical trial reported by the researchers whose studies Dr Carifi cites to forward this point, neither impression cytologic nor immunochemical markers were used to establish the diagnosis of LSCD. In fact, presently a combination of clinical signs, including the absence of the limbal palisades, persistent epithelial defects, and conjunctivalization of the cornea, are considered to be the gold standard for the diagnosis of LSCD.