Making the Case for DALK

Clinical Report: Making the Case for DALK

Overview

Sheraz Daya describes deep anterior lamellar keratoplasty (DALK) as a partial-thickness alternative to penetrating keratoplasty (PK) for eligible patients with corneal disease and a healthy endothelium. He emphasizes preservation of recipient tissue and avoidance of open-sky surgery, while identifying perceived complexity and a steep learning curve as barriers to wider adoption in the United States.

Background

Keratoconus and other corneal ectatic disorders may require keratoplasty when conservative treatment is unsuccessful or disease is advanced. DALK replaces anterior corneal tissue while preserving the recipient endothelium and Descemet’s membrane; PK replaces the full thickness of the cornea. The source describes rejection, graft failure, and complications associated with open-sky surgery as concerns with PK. A 2026 evidence-based keratoconus guideline conditionally recommends DALK over PK for severe stage IV keratoconus.

Data Highlights

Measure	Reported finding	Source
UK registry rejection and failure in keratoconus	7% over 3 years	Sheraz Daya, as reported in the article
Survival after regrafting	About 50%	Sheraz Daya, as reported in the article
Mean duration of full-thickness grafts	About 17–20 years	Sheraz Daya, as reported in the article
Expulsive hemorrhage risk during PK	0.5–1%	Sheraz Daya, as reported in the article
Glaucoma reported after PK	19–30%	Literature range cited by Daya
US DALK volume and estimated eligibility	About 900–1,000 cases annually versus approximately 40,000 eligible cases	Sheraz Daya, as reported in the article
PK versus DALK visual acuity at 1 year	No significant difference; Hedges g 0.03, p=0.71	2025 systematic review and meta-analysis of 47 studies and 27,018 eyes, as summarized in supplied context

Key Findings

Daya reports that DALK preserves the recipient’s endothelial layer when it is healthy, rather than replacing it with a full-thickness graft.
He cites UK registry data indicating a 7% chance of rejection and failure within 3 years after keratoplasty for keratoconus, and estimates graft survival after regrafting at about 50%.
Daya states that full-thickness grafts last a mean of about 17–20 years, whereas a lamellar graft may change shape while remaining clear.
PK requires an open-sky period; Daya cites an expulsive hemorrhage risk of 0.5–1% and a literature-reported glaucoma range of 19–30%, and says these complications do not occur with DALK.
The supplied 2025 meta-analysis found no significant difference in 1-year best-corrected visual acuity or astigmatism between PK and DALK; it reported higher graft rejection risk and lower graft failure risk with PK compared with DALK.
The 2026 keratoconus guideline conditionally recommends DALK rather than PK for severe stage IV keratoconus and considers big-bubble and manual DALK techniques acceptable, with no clinically relevant difference in effectiveness or safety demonstrated by available evidence.

Clinical Implications

For patients with advanced keratoconus and a healthy endothelium, the supplied guideline supports considering DALK rather than PK, while the comparative evidence summarized here indicates similar 1-year visual acuity and astigmatism but differing rejection and failure risks. Daya identifies procedure duration, perceived complexity, and the learning curve as barriers to adoption and describes systematic surgical training as the focus of the AAO workshop.

Conclusion

DALK preserves recipient posterior corneal tissue and avoids the open-sky phase of PK, but its uptake in the United States remains limited according to Daya. Guideline and comparative evidence in the supplied context support its role in severe keratoconus while documenting relevant outcome trade-offs.