New technique of Deep Anterior Lamellar Keratoplasty

Deep anterior lamellar keratoplasty (DALK) is a surgical technique for cornea replacement, which the healthy host corneal endothelium is preserved. Keratoconus patients are those who benefit most from a successful DALK procedure, once the endothelium of these patients is usually normal and should therefore be maintained. Several studies comparing visual outcomes between penetrating keratoplasty (PK) and DALK have shown similar results1-4. Initially, DALK was performed using manual corneal dissection5. The greatest limitation of early DALK techniques was that they left variable amounts of residual stroma. This provided a scaffold for vascular ingrowth or led to variable amounts of postoperative scarring in the interface due to the remaining vessels. Also, the uneven or irregular dissection plane could impair visual acuity. The main disadvantage of DALK is the significant learning curve to master the technique. Moreover, it is time-consuming procedure, especially when the stroma has to be manually separated from the Descemet ́s membrane. Anwar and Teichmann’s6 big-bubble technique of injecting air into the corneal stroma to isolate Descemet’s membrane markedly improved DALK outcomes. Removing the overlying stroma completely created a clear graft interface without irregularities. Visual outcomes are excellent, and postoperative interface problems from vascularization of the recipient corneal bed are minimal. A variant of the big-bubble technique in deep anterior lamellar keratoplasty (DALK) assisted by the femtosecond laser has been described, with good and reproducible results7,8. The present technique allows a deep and smooth separation of corneal stroma from Descemet ́s membrane, by an interlamela cleavage plane created by a nylon wire.