DALK is a partial-thickness corneal transplant for advanced keratoconus. It replaces the diseased corneal stroma but retains your own healthy endothelium — the inner cell layer whose rejection is the main cause of late graft failure. That is why DALK delivers equivalent vision to a full-thickness transplant but with far longer graft survival (10-year survival typically over 90% versus 60–75% for PK).
What is DALK?
In keratoconus the cornea thins and bulges into a cone, distorting vision. When spectacles, contact lenses and cross-linking can no longer give useful vision — or scarring has developed — a transplant is considered. DALK replaces only the diseased front layers, leaving your own Descemet’s membrane and endothelium in place. Because the most consequential form of graft rejection (endothelial rejection) is essentially removed as a failure mode, DALK is the preferred keratoplasty for keratoconus, especially in younger patients with a 30–50 year visual lifetime ahead of them.
It is performed by consultant corneal surgeons at our South England partner clinics, with UK-wide guidance through your pathway. DALK is reserved for advanced disease because it commits you to a 12–18 month suture-care course and lifelong protective-eyewear advice — so earlier steps in the keratoconus pathway are always considered first.
The keratoconus treatment pathway
How DALK is performed
DALK is performed under general anaesthetic or a sub-Tenon’s block and takes around 90 minutes. Using the big-bubble technique, the surgeon injects air into the deep stroma to cleave the diseased layers cleanly off your own Descemet’s membrane, removes the diseased stroma, and stitches a matched donor cornea (with its endothelium removed) into place with around 16 fine interrupted 10-0 nylon sutures. An optional femtosecond laser-assisted upgrade (femto-DALK) can be used for the trephination. In about 10–15% of cases a micro-perforation means the surgeon converts to a full-thickness transplant (PK); this is a planned decision built into your consent, not a complication.
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Book your corneal assessmentRecovery & suture-care timeline
Weeks 1–2
A foreign-body sensation or mild ache is normal as the surface heals over the suture knots, managed with simple analgesia and lubricants. Topical steroid drops are started.
Months 2–3
Useful vision returns — enough for daily activities like reading large print and watching television — as the surface settles.
Months 6–18
Best-corrected vision is unlocked by gradual, topography-guided selective suture removal, flattening the steepest meridia first. Vision improves in step-changes at each visit.
Ongoing
About two-thirds reach the UK driving standard with spectacles; the rest achieve best vision with rigid gas-permeable or scleral lenses. Protective eyewear is advised for contact sport for life.
How much does DALK cost?
UK 2026 self-pay DALK costs £8,500–£14,000 per eye all-inclusive of the donor cornea (sourced from NHS Blood and Transplant or an equivalent BSI-4 eye bank, typically £1,500–£2,500 within the bundle), the consultant corneal surgeon, sterile theatre, anaesthetist where needed, sutures and consumables, and standard reviews from day 1 to week 12. The optional femto-DALK upgrade adds £1,500–£3,000. Beyond the 12-week bundle, the long suture-care phase is usually billed per visit (monthly reviews £180–£280; topography-guided suture-removal visits £250–£450). Rigid gas-permeable lens fitting afterwards is typically £250–£500. We quote your full pathway in writing before surgery — see our price list.
DALK FAQs
How much does private DALK surgery cost in London in 2026?
UK 2026 self-pay DALK costs £8,500–£14,000 per eye all-inclusive of the donor cornea sourced from NHS Blood and Transplant or an equivalent BSI-4 eye bank (typically £1,500–£2,500 within the bundle), the consultant corneal surgeon, sterile operating theatre, consultant anaesthetist where general anaesthesia is used, sutures and intraoperative consumables, and the standard postoperative reviews from day 1 to week 12. The optional femtosecond laser-assisted DALK upgrade (femto-DALK) adds £1,500–£3,000 to the base price. Beyond the 12-week surgical bundle, the long suture-care phase is typically billed per visit: monthly slit-lamp reviews months 1–6 at £180–£280, and topography-guided selective suture-removal visits months 6–18 at £250–£450 per visit. Rigid gas-permeable contact lens fitting after sutures are out is typically £250–£500.
Is DALK better than PK for keratoconus?
For keratoconus in eyes with healthy recipient endothelium, DALK is the modern standard of care. The single most important determinant of long-term keratoplasty survival is endothelial rejection — the immunologic attack by the recipient on the donor endothelium — which is the principal cause of late graft failure in PK eyes. DALK retains the recipient’s own healthy endothelium and therefore essentially eliminates endothelial rejection as a failure mode. Systematic reviews show equivalent best-corrected visual acuity between DALK and PK in keratoconus, with materially lower endothelial cell loss, lower long-term graft failure and longer expected survival (10-year DALK survival typically >90% versus 60–75% for PK). The trade-off is operative complexity and a slower visual recovery; for keratoconus this trade is overwhelmingly worth it.
How long does it take to see well after DALK?
Visual recovery after DALK has two phases. Useful vision — seeing well enough for daily activities like reading large print and watching television — typically returns at 2–3 months as the corneal surface settles. Best-corrected vision — the visual potential the graft will ultimately reach — takes 12–24 months and is unlocked by gradual topography-guided suture removal from month 6 onwards. The months in between are slow steady improvement punctuated by step-changes at each suture-removal visit. Some patients reach 6/6 with spectacles; others need rigid gas-permeable contact lens fitting. The slower recovery compared with PK is a real disadvantage to discuss candidly, but is outweighed by the longer graft survival in most patients with a long expected visual lifetime.
Can I have DALK on the NHS?
Yes. DALK is available at all UK tertiary corneal centres through NHS Blood and Transplant donor tissue allocation, including Moorfields, Manchester Royal Eye Hospital, Bristol Eye Hospital and King’s College Hospital. NHS DALK is performed by the same consultant corneal surgeons who work privately and uses the same NHSBT donor tissue, so the operation is technically identical. The difference is waiting time: elective DALK referrals commonly wait 12–24 months for a surgical date in 2026. For patients with deteriorating contact-lens tolerance, post-hydrops scarring or progressing visual loss, private intervention can compress the pathway from around 18 months to 4–6 weeks. Many patients use a hybrid pathway — NHS for diagnosis and specialist contact-lens trial, private for the surgery and suture-care phase.
How long does a DALK graft last?
DALK graft survival is one of the longest of any keratoplasty type. Published cohorts consistently show 10-year graft survival exceeding 90% for DALK in keratoconus, compared with 60–75% for PK in the same indication. The principal reason is retention of the recipient endothelium, which eliminates endothelial rejection as a failure mode. The remaining causes of late DALK failure are stromal rejection (5–15% lifetime risk, usually reversible with topical steroid) and, rarely, recurrence of an underlying stromal dystrophy. For a younger keratoconus patient, the difference between a 30-year DALK graft and a 15-year PK graft is decisive.
Can I have DALK if my keratoconus is mild?
Mild keratoconus does not need a transplant. Modern management follows a stepped pathway: observation in stable mild disease with good spectacle or soft-lens vision; corneal cross-linking when progression is documented in eyes with corneal thickness >400 microns; intracorneal ring segments (such as Intacs) when cross-linking has stabilised the cone but vision remains poor with lenses; rigid gas-permeable or scleral contact lenses; and DALK transplant only when earlier interventions have not delivered adequate visual function, scarring is present, or contact-lens tolerance has failed. DALK is reserved for advanced disease because it commits you to a 12–18 month course and lifelong protective-eyewear advice. For mild keratoconus the stepped pathway gives equally good or better outcomes with much less surgical commitment.