Evolving DALK techniques provide improved management of keratoconus

Improvements in deep anterior lamellar keratoplasty (DALK) techniques, as well as greater surgical familiarity with that particular approach, has elevated DALK to first-choice treatment modality in cases where keratoplasty is indicated in keratoconus, José Güell MD told the audience in his EuCornea Medal Lecture at the Opening Ceremony of the 5th EuCornea Congress.

“In my practice, DALK, whether Descemetic or pre-Descemetic, is the first-choice option for these keratoconus patients that need to undergo keratoplasty. The best-corrected visual acuity and the quality of vision are equivalent to that achieved with penetrating keratoplasty (PK) but the long-term survival clearly favours DALK,” said Dr Güell.

Management of keratoconus depends on the degree of ectasia present, said Dr Güell. “Most keratoconus patients worldwide are being managed quite successfully with spectacles and/or contact lenses,” he said.

Other options for management include corneal stroma collagen crosslinking, intracorneal ring segments, toric phakic and pseudophakic intraocular lenses.

More advanced cases of keratoconus, however, often require surgical intervention to restore corneal anatomy and improve eyesight, with common surgical options including PK  and DALK.

The latter procedure allows surgical replacement of the recipient corneal stroma, leaving behind healthy Descemet’s membrane (DM) and endothelium. This reduces the risk of allograft endothelial rejection and late graft failure, said Dr Güell.

While PK used to be the go-to procedure for advanced keratoconus patients, the procedure carries a greater risk of immunological rejection than DALK and is now no longer automatically the first choice  of surgery.

The main advantages of DALK include the fact that it is extraocular surgery, carries no risk of endothelial rejection, preserves the host endothelium, encourages faster wound healing, and entails a short topical corticosteroid regimen. Furthermore, the pre-Descemet’s plane lamellar dissection also reduces the incidence and severity of interface-related complications.

DALK procedures have evolved in recent years, said Dr Güell, and several surgical approaches, mainly based on Anwar’s big-bubble technique, are usually employed.

Dr Güell has recently introduced a refinement of the big-bubble technique that employs pressure exacted by a cohesive viscoelastic device in order to detach Descemet’s membrane. This approach may offer a gentler, more controlled dissection and better visualisation, he said.

“In our hands the visco-bubble technique for DALK gives better visualisation, reduces the risk of perforation, and is reproducible,” he said, adding that this still needs to be validated in controlled clinical studies.

Looking ahead, Dr Güell said that he was hopeful that corneal transplantation surgery will become a “rare exception” in the near future thanks to new strategies that are emerging to manage keratoconus, particularly in younger patients.