Deep Anterior Lamellar Keratoplasty (DALK) is a specialized partial-thickness corneal transplant that replaces diseased outer and middle corneal layers (the epithelium and stroma) while preserving the patient's own healthy inner layers (Descemet's membrane and endothelium). By retaining the host endothelium, DALK virtually eliminates the risk of endothelial graft rejection, provides superior long-term tectonic stability, and significantly reduces intraocular surgical risks compared to full-thickness penetrating keratoplasty. It is the preferred surgical option for advanced keratoconus, corneal ectasia, and stromal dystrophies or scars where the innermost corneal layer remains healthy.
DALK (Deep Anterior Lamellar Keratoplasty)
Deep Anterior Lamellar Keratoplasty (DALK) is a specialized partial-thickness corneal transplant that replaces diseased outer and middle corneal layers (the epithelium and stroma) while preserving the patient's own healthy inner layers (Descemet's membrane and endothelium). By retaining the host endothelium, DALK virtually eliminates the risk of endothelial graft rejection, provides superior long-term tectonic stability, and significantly reduces intraocular surgical risks compared to full-thickness penetrating keratoplasty. It is the preferred surgical option for advanced keratoconus, corneal ectasia, and stromal dystrophies or scars where the innermost corneal layer remains healthy.
DALK (Deep Anterior Lamellar Keratoplasty)
Surgery Name
DALK (Deep Anterior Lamellar Keratoplasty)
Speciality
Ophthalmology (Cornea & Anterior Segment)
Duration
Usually 60–120 minutes
Anaesthesia
Local anaesthesia with sedation, or general anaesthesia
Hospital Stay
Day-care procedure or short overnight stay
Recovery Time
Initial healing in weeks; visual stabilization over 6–12 months
Procedure Type
Partial-thickness (lamellar) corneal transplant
Insurance Coverage
Usually covered when medically indicated
Cost Range in India
Varies based on hospital tier, donor tissue source, and technique
Success Rate
High graft survival (>90% at 5 years); eliminates endothelial rejection
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Symptoms and Signs of Corneal Conditions That May Be Treated with DALK
DALK is indicated for progressive diseases affecting the corneal stroma where endothelial function is preserved. Symptoms arise from structural distortion, irregular astigmatism, or stromal opacification, and may include:
Progressive blurring, haziness, or visual distortion (ghosting and monocular polyopia) that cannot be satisfactorily corrected with spectacles.
Frequent prescription changes with rapidly escalating irregular corneal astigmatism and myopia.
Severe glare, halos around lights, and poor contrast sensitivity, particularly in low-light and night driving conditions.
Contact lens intolerance or inability to achieve a stable fit with rigid gas permeable (RGP) or scleral contact lenses due to advancing corneal steepening.
Visible corneal opacification, haze, or focal stromal scarring resulting from prior keratitis, trauma, or stromal dystrophies.
Sudden vision loss, severe pain, and corneal clouding if acute corneal hydrops occurs due to a break in Descemet's membrane in advanced keratoconus.
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What Conditions Lead to DALK?
The cornea comprises five primary anatomical layers: the epithelium, Bowman's layer, the stroma (accounting for 90% of corneal thickness), Descemet's membrane, and the endothelium. The endothelium acts as an active fluid pump to maintain corneal clarity. When disease, scarring, or ectasia compromises the stroma but spares endothelial cell density and function, DALK selectively replaces the diseased stroma while retaining the patient's own endothelium.
Conditions Commonly Treated with DALK
Advanced Keratoconus: Progressive bilateral thinning, biomechanical weakening, and conical steepening of the cornea, particularly when contact lenses are no longer tolerated and corneal cross-linking (CXL) is no longer sufficient.
Corneal Stromal Scars: Non-progressive opacities resulting from prior trauma, healed microbial keratitis (e.g., bacterial, fungal, or quiescent herpes simplex keratitis), or resolved hydrops.
Corneal Stromal Dystrophies: Inherited, bilateral stromal conditions such as granular, lattice, or macular corneal dystrophies that lead to progressive deposition of proteinaceous material.
Iatrogenic Corneal Ectasia: Post-refractive ectasia developing after LASIK or PRK when the residual stromal bed weakens and bulges forward.
Other Non-Inflammatory Corneal Thinning Disorders: Including pellucid marginal degeneration (PMD) and keratoglobus, where anterior lamellar replacement provides tectonic and visual restoration.
Causes and Risk Factors
Keratoconus is the primary indication for DALK worldwide. Chronic vigorous eye rubbing, atopic allergies, genetic predisposition, and underlying connective tissue disorders are major contributing risk factors. It typically manifests during puberty or early adulthood and may progress through the third and fourth decades.
Vigorous Eye Rubbing: Repeated mechanical trauma directly promotes enzymatic degradation of the corneal collagen matrix and accelerates ectatic progression.
Atopic & Allergic Eye Disease: Severe vernal keratoconjunctivitis (VKC) and atopic dermatitis provoke chronic pruritus, frequent rubbing, and ocular surface inflammation.
Genetic & Familial Factors: Positive family history is documented in approximately 5% to 10% of keratoconus cases, along with autosomal dominant inheritance in several stromal dystrophies.
Connective Tissue Disorders: Higher incidence observed in patients with Down syndrome, Marfan syndrome, Ehlers-Danlos syndrome, and osteogenesis imperfecta.
Prior Ocular Trauma or Severe Infections: Deep mechanical lacerations or severe keratitis resulting in permanent central stromal opacification.
What is DALK?
Deep Anterior Lamellar Keratoplasty (DALK) is an advanced anterior lamellar corneal transplantation technique. The procedure selectively excises the entire diseased corneal stroma down to Descemet's membrane (a thickness of only 10 to 15 microns) and replaces it with a matching donor stromal graft without donor endothelium. Because the patient's native endothelial monolayer is preserved intact, endothelial allograft rejection—the most common cause of long-term graft failure in full-thickness Penetrating Keratoplasty (PK)—cannot occur. Furthermore, maintaining an intact Descemet's membrane preserves an extraocular closed-system environment during surgery, substantially lowering the risks of expulsive choroidal haemorrhage, endophthalmitis, and secondary glaucoma.
Selective Stromal Replacement: Completely removes opacified, scarred, or ectatic anterior tissue while leaving the host endothelium untouched.
Elimination of Endothelial Rejection: By retaining the host's own endothelial cells, lifelong risk of endothelial rejection is eliminated, leading to excellent long-term graft survival.
Enhanced Structural & Tectonic Strength: Preserving the host deep corneal architecture provides greater globe integrity and resistance to blunt trauma compared to full-thickness grafts.
Reduced Steroid Burden: Shorter course and lower concentration of topical corticosteroid therapy are needed, reducing the incidence of steroid-induced glaucoma and cataracts.
Do You Really Need Surgery?
DALK is a major surgical procedure indicated when non-surgical treatments and conservative interventions are no longer sufficient to provide functional vision. A cornea specialist will assess your candidacy based on several key clinical criteria:
Failure of Optical Correction: Spectacles, hybrid lenses, rigid gas permeable (RGP), or scleral lenses no longer provide adequate visual acuity, or chronic lens intolerance prevents daily wear.
Advanced Ectasia Beyond CXL: Corneal thinning is too advanced (pachymetry below 350–400 microns) or steep (keratometry >58–60 D) for corneal cross-linking (CXL) to be safe or effective.
Significant Visual Impairment from Stromal Scars: Central stromal scarring or inherited dystrophic deposits substantially impairing reading, driving, and occupational activities.
Demonstrated Endothelial Health: Specular microscopy and clinical assessment confirm healthy endothelial cell density and morphology, confirming that partial-thickness surgery is appropriate.
What Happens if You Delay Treatment?
While DALK is generally an elective visual rehabilitation procedure, delaying surgery in the setting of severe progressive ectasia or active thinning can lead to clinical complications and reduce surgical success. Treatment timing should be determined in consultation with your cornea specialist.
Progressive Visual Deterioration: Ongoing corneal steepening, irregular astigmatism, and high-order aberrations cause severe visual disability.
Acute Corneal Hydrops: Severe thinning can result in spontaneous rupture of Descemet's membrane, causing sudden fluid influx, marked corneal oedema, intense pain, and subsequent deep central scarring.
Loss of Candidacy for DALK: Post-hydrops scarring or chronic endothelial decompensation may prevent safe pneumodissection of Descemet's membrane, necessitating a full-thickness penetrating keratoplasty (PK) with its higher rejection risks.
Extreme Thinning & Spontaneous Perforation Risk: In rare cases of neglected keratoglobus or extreme ectasia, minor trauma can lead to corneal perforation.
When Should You See a Cornea Specialist? (Warning Signs)
DALK Techniques and Related Corneal Transplant Options
Multiple microsurgical and laser techniques are used to separate the stroma from Descemet's membrane during DALK, tailored to corneal anatomy and surgeon preference:
Big-Bubble Technique (Anwar Technique)
The most widely performed DALK technique. A fine 27G or 30G needle or specialized cannula is inserted into the deep posterior stroma to inject air. The air bubble cleaves the pre-Descemet's plane, forming a large bubble ('Big Bubble') that cleanly detaches the stroma from Descemet's membrane. This allows complete stromal excision down to a smooth, bare Descemet membrane, yielding optimal post-operative optical clarity.
Manual Layer-by-Layer (Melles) Dissection
When a big bubble cannot be achieved or in corneas with deep scarring (such as resolved hydrops or deep trauma), the surgeon manually dissects the stroma layer-by-layer using specialized micro-delaminators and viscodissection. While a microscopic layer of pre-Descemetic stroma may remain, visual outcomes remain excellent and the procedure avoids full-thickness conversion.
Femtosecond Laser-Assisted DALK (F-DALK)
A femtosecond laser creates computer-guided, customized trephination profiles (e.g., zig-zag, top-hat, or mushroom configurations) in both the recipient and donor corneas. This precision enhances wound apposition, accelerates biomechanical wound healing, and may facilitate earlier suture removal with lower post-operative astigmatism.
Comparison of Treatment Options
Treatment Option
Best For
Rejection Risk
Recovery Time
Corneal Cross-Linking (CXL)
Early to moderate progressive keratoconus with corneal thickness >400 µm
None (non-transplant procedure)
1 to 2 weeks for surface recovery; stabilization over 1–3 months
Rigid Gas Permeable (RGP) / Scleral Contact Lenses
Mild to advanced irregular astigmatism with clear corneal stroma
None (optical device)
Immediate upon fitting; ongoing lens maintenance
DALK (Deep Anterior Lamellar Keratoplasty)
Advanced keratoconus, stromal scarring, or dystrophies with a healthy endothelium
Very low (endothelial rejection eliminated; stromal/epithelial rejection rare)
Initial recovery in weeks; visual stabilization over 6–12 months
Penetrating Keratoplasty (PK, Full-Thickness)
Full-thickness corneal opacity, endothelial failure, or failed DALK/macroperforation
Preparing for DALK
What Happens on the Day of Surgery?
Before and After DALK
Before Surgery
After Surgery
Severe visual distortion, monocular ghosting, glare, and progressive irregular astigmatism not correctable by glasses
Gradual visual recovery over months; vision sharpens significantly as surface epithelium heals and sutures are selectively removed or adjusted
Contact lens intolerance due to extreme corneal steepening, cone elevation, or chronic apical abrasions
Cornea achieves a regular, tectonic curvature; glasses or soft/RGP lenses can be comfortably fitted once sutures stabilize
High lifelong risk of irreversible endothelial rejection and graft failure if treated with full-thickness penetrating keratoplasty
Endothelial rejection eliminated; lifelong graft survival is significantly higher with lower topical steroid dependency
Progressive stromal thinning, cone ectasia, scarring, or risk of acute hydrops
Anaesthesia is administered to ensure comfort, the surgical field is prepared under sterile conditions, and matched donor corneal tissue is verified.
Anaesthesia: Administered as a regional peribulbar block with sedation or general anaesthesia to keep the eye comfortable and motionless.
Donor Tissue Preparation: The donor corneoscleral button is mounted on an artificial anterior chamber, where its endothelium and Descemet's membrane are carefully stripped and peeled off.
Step 2
Step 2
The procedure typically takes between 60 and 120 minutes. Duration varies depending on corneal thickness, scarring severity, whether the big bubble is achieved on the first attempt or manual dissection is required, and surgical complexity. Patients should anticipate spending 4 to 6 hours at the surgical centre including pre-operative preparation and post-anaesthetic recovery.
Risks and Complications of DALK
Complication
Risk Level
What It Is
How We Prevent / Treat It
Descemet's Membrane Perforation (Intraoperative)
Recognized intraoperative risk (occurs in ~5% to 15% of cases)
A microscopic tear or larger opening in the thin Descemet's membrane during pneumodissection or stromal excision.
Meticulous depth control during cannula insertion. Microperforations are managed with an intracameral air bubble tamponade while completing DALK; macroperforations may require conversion to Penetrating Keratoplasty (PK).
Double Anterior Chamber (Pseudo-chamber)
Uncommon (occurs in ~2% to 6% of cases)
A post-operative fluid collection separating the host Descemet's membrane from the posterior surface of the donor graft.
Confirmed on post-op slit-lamp and AS-OCT. Mild detachments often resolve spontaneously; persistent fluid is treated with an in-office intracameral air/gas injection (rebubbling) to re-appose Descemet's membrane to the graft.
Postoperative Astigmatism
Common (expected during active suture healing)
Irregular or high regular corneal curvature resulting from differential suture tension or wound healing dynamics.
Recovery Timeline After DALK
Time Period
Expected Recovery Milestones
First 24 to 48 Hours
Vision is blurry, light-sensitive, and watery; mild aching and grittiness are normal. Epithelium begins covering the graft. Wear the eye shield at all times.
Weeks 1 to 4
Surface epithelium completely heals; eye irritation and photophobia settle. Prescribed antibiotic and steroid drops are applied regularly. Light daily activities can be resumed.
Months 2 to 6
Graft-host junction achieves tectonic stability. Topical steroids are tapered to low-dose maintenance. Selective suture removal may begin to correct high astigmatism.
Months 6 to 12+
Progressive visual sharpening. Suture removal is completed based on corneal topography and healing status (usually between 10 and 18 months). Final refraction for glasses or contact lenses is prescribed.
Postoperative Care
Follow-Up Visits After DALK
Close clinical follow-up is essential to monitor graft integration, manage suture tension, and optimize visual recovery:
1Day 1 (24 Hours Post-Op): Assessment of graft apposition, epithelial healing, intraocular pressure, and absence of double anterior chamber.
2Week 1 to 2: Verification of complete epithelial closure, suture integrity, and control of post-operative inflammation.
3Month 1, 3, and 6: Monitoring of graft clarity, steroid response (intraocular pressure check), and topographic assessment of astigmatism.
4Month 9 to 18: Selective suture removal guided by corneal topography to reduce astigmatism, followed by final visual rehabilitation.
5Annual Long-Term Review: Routine yearly examinations to ensure ongoing corneal health and stability.
Warning Signs to Watch After DALK
Contact your cornea specialist or emergency eye clinic immediately if you experience the 'RSVP' warning signs of graft rejection or complications:
1Redness: Increasing redness in or around the operated eye.
2Sensitivity: New or worsening extreme sensitivity to light (photophobia).
3Vision: Sudden drop, haziness, cloudiness, or significant blurring in vision.
4Pain: Persistent, new, or throbbing eye pain not relieved by mild analgesics.
5Discharge or Suture Issues: Yellowish/greenish discharge, sharp foreign body sensation, or a visible loose or broken suture.
6Trauma: Any direct blow or accidental trauma to the operated eye.
Questions to Ask Your Surgeon
Important questions to discuss with your cornea specialist during your consultation:
1Is my corneal endothelium healthy enough for DALK, or might I require a full-thickness Penetrating Keratoplasty (PK)?
2What is the estimated likelihood of intraoperative conversion to PK in my specific case?
3Which dissection technique (Big-Bubble, manual delamination, or femtosecond laser) do you plan to use?
4How long will the corneal sutures remain in place, and how will selective suture removal be scheduled?
5What visual acuity can I realistically expect, and will I need glasses or specialty contact lenses after healing?
6When will it be safe for me to return to work, drive, exercise, and resume normal daily activities?
7How is the donor corneal tissue screened, tested, and procured through the eye bank?
8What emergency warning signs should prompt me to contact the clinic immediately outside normal hours?
Frequently Asked Questions about DALK
What is DALK?
Deep Anterior Lamellar Keratoplasty (DALK) is a partial-thickness corneal transplant that removes the diseased outer and middle corneal layers (epithelium and stroma) while preserving the patient's own healthy inner layers (Descemet's membrane and endothelium).
How is DALK different from a full corneal transplant?
A full-thickness transplant (Penetrating Keratoplasty, PK) replaces all layers including donor endothelium, carrying a lifelong risk of endothelial rejection. DALK keeps your own endothelium, eliminating endothelial rejection, enhancing tectonic wound strength, and significantly reducing intraocular surgical risks.
Is DALK suitable for everyone with keratoconus?
Find the Right Specialist for DALK
Choosing an Expert Corneal Specialist
DALK is a technically demanding microsurgical procedure. When selecting a surgical centre and cornea specialist, consider the following key factors:
1Board-certified ophthalmologist with accredited fellowship training in Cornea, External Diseases, and Refractive Surgery, and extensive experience in lamellar keratoplasty.
2High surgical volume in both Big-Bubble pneumodissection and manual lamellar dissection techniques.
3Partnership with an accredited, high-standard eye bank ensuring rigorously screened, high-quality donor corneal tissue.
4Access to advanced diagnostic infrastructure, including high-resolution Scheimpflug tomography, specular microscopy, and anterior segment OCT.
Clinical Guidelines and Evidence
Extensive international peer-reviewed clinical studies, cornea registry data, and ophthalmic guidelines establish DALK as the gold standard for stromal corneal diseases with healthy endothelium. Large comparative trials and registry reports (including the Australian Corneal Graft Registry) demonstrate that DALK achieves visual acuity and refractive outcomes comparable to Penetrating Keratoplasty (PK) while offering significant long-term advantages: elimination of endothelial allograft rejection, superior 5- to 10-year graft survival rates (>90%), higher endothelial cell density retention, and preservation of globe tectonic integrity against blunt trauma. Intraoperative Descemet's membrane perforation remains a recognized occurrence (5–15%), with most microperforations successfully managed without converting to full-thickness surgery.
Study / Guideline
Core Metric Settled
Direct Impact on Surgical Practice
Link to Study / Summary
Anwar & Teichmann - Big-Bubble Technique in DALK
Described the big-bubble technique for pneumatic cleavage of the deep stroma from Descemet's membrane, establishing the primary surgical technique for modern DALK.
Related Conditions
Corneal conditions related to or treated by DALK include:
1Keratoconus: Progressive corneal thinning and ectasia requiring stromal replacement when non-surgical options fail.
2Pellucid Marginal Degeneration (PMD) & Iatrogenic Ectasia: Peripheral and central corneal ectatic disorders.
3Corneal Stromal Dystrophies: Inherited disorders including granular, macular, and lattice dystrophies.
4Post-Infectious or Post-Traumatic Stromal Scars: Quiescent anterior or mid-stromal opacities following healed keratitis or trauma.
Related Procedures
Complementary and alternative corneal procedures include:
1Corneal Cross-Linking (CXL): A collagen-strengthening procedure used to halt keratoconus progression in early-to-moderate stages.
2Penetrating Keratoplasty (PK): Full-thickness corneal transplantation performed when the endothelium is diseased or full-thickness scarring is present.
3Endothelial Keratoplasty (DMEK / DSAEK): Selective inner-layer corneal transplants indicated for endothelial dysfunction (e.g., Fuchs' dystrophy), preserving the host stroma.
4Intracorneal Ring Segments (ICRS): Semi-rigid PMMA ring segments implanted into the mid-stroma to flatten and regularize the cornea in selected mild-to-moderate keratoconus.
Related Specialty
Ophthalmology.
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You should seek prompt or urgent evaluation from a cornea specialist if you experience any of the following symptoms:
Rapid worsening or distortion of vision despite recent spectacle or contact lens adjustments.
Inability to wear contact lenses due to pain, frequent lens dislodgement, or apical corneal abrasions.
Sudden onset of severe eye pain, extreme photophobia, and a cloudy, milky-white appearance of the cornea (suggestive of acute hydrops—requires emergency assessment).
New or expanding white patches, redness, or discharge on a previously scarred cornea.
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Intraoperative Conversion to Penetrating Keratoplasty (PK)
In approximately 5% to 15% of cases, an intraoperative macroperforation of Descemet's membrane may occur during dissection. When the tear cannot be safely managed with an air bubble tamponade, the surgeon immediately converts the procedure to a full-thickness Penetrating Keratoplasty (PK). Conversion is a planned, standard intraoperative safety measure and is discussed during pre-operative consent.
Higher (endothelial allograft rejection risk persists throughout life)
12 to 18+ months for visual stabilization
Doctor's Recommendation
Corneal treatment follows a step-up approach tailored to disease stage, anatomical depth, and endothelial viability. In early to moderate progressive keratoconus with functional vision, corneal cross-linking (CXL) combined with specialty contact lenses is the standard of care to halt progression. When advanced ectasia, significant stromal thinning, or dense scarring develops but the endothelium remains healthy, DALK is the gold-standard surgical option because it preserves the natural endothelium and avoids lifelong endothelial rejection. Full-thickness penetrating keratoplasty (PK) is reserved for cases involving endothelial disease, full-thickness scars, or intraoperative macroperforation during DALK. Your cornea specialist will determine the optimal procedure following comprehensive corneal tomography and endothelial specular microscopy.
Thorough pre-operative diagnostic mapping ensures accurate surgical sizing and confirms endothelial health prior to DALK:
Corneal Topography & Tomography (e.g., Pentacam, Galilei): Maps anterior and posterior corneal curvature, elevation, and pachymetric thickness profiles.
Specular Microscopy: Measures endothelial cell density (ECD) and cell morphology to confirm endothelial viability.
Anterior Segment OCT (AS-OCT): Quantifies exact depth of corneal scars and remaining stromal thickness above Descemet's membrane.
Comprehensive Ophthalmic Examination: Evaluates intraocular pressure, ocular surface health, and exclusion of active blepharitis or allergy.
Pre-Anaesthetic Clearance: Routine blood investigations, ECG, and physician review tailored to systemic health and planned anaesthesia.
Adherence to medication and fasting instructions is critical for a smooth surgical course:
Medication Disclosure: Inform your surgical team of all prescription medications, over-the-counter drugs, supplements, and drug allergies. Do not discontinue prescribed medications unless specifically instructed by your treating physician.
Blood Thinners: If you take antiplatelet or anticoagulant drugs, management will be coordinated between your cardiologist and cornea surgeon.
Contact Lens Discontinuation: Discontinue rigid gas permeable (RGP) or scleral lenses for 2 to 4 weeks (and soft lenses for 1 week) prior to final pre-operative mapping to allow the cornea to regain its baseline shape.
Allergy & Ocular Surface Control: Treat active ocular allergies or blepharitis with prescribed anti-inflammatory drops to optimize the surgical field.
Fasting Guidelines: If having sedation or general anaesthesia, do not consume solid food for 6 hours prior to surgery; clear fluids may be permitted up to 2 hours before, as directed by your anaesthesia team.
Prepare the following items and arrangements for the day of surgery:
Government photo identification, hospital registration card, and health insurance policy documents.
All prior ophthalmic reports, corneal topography scans, and a written list of current medications and dosages.
A responsible adult companion to escort you home, as your operated eye will be patched and vision will be impaired.
Dark sunglasses to wear during the journey home to minimize light sensitivity.
Comfortable, loose-fitting front-buttoned or zippered clothing to avoid pulling garments over your head after surgery.
Preparation in the day-care or surgical admission unit involves standard pre-operative checks:
Confirmation of patient identity, surgical consent, and marking of the operative eye.
Verification of donor corneal tissue quality, cell count, and serological clearance documentation.
Administration of pre-operative eye drops, including pupil-constricting or dilating drops (as indicated), prophylactic antibiotic drops, and pressure-lowering medications.
Administration of anaesthesia: a local peribulbar/retrobulbar block with mild intravenous sedation, or induction of general anaesthesia to ensure complete comfort.
DALK typically requires 60 to 120 minutes depending on anatomical complexity, dissection technique, and whether manual dissection is needed:
Sterile Preparation: The periocular area is disinfected with povidone-iodine and sterile drapes are placed; an eyelid speculum keeps the eye open comfortably.
Partial-Thickness Trephination: A calibrated suction or manual trephine creates a precise partial-thickness circular incision (typically 7.5 to 8.5 mm in diameter) through approximately 60% to 80% of host corneal depth.
Big-Bubble Pneumodissection: A cannula is inserted into the deep stroma to inject sterile air, forming a bubble that detaches the stroma from Descemet's membrane.
Stromal Excision: The anterior diseased stroma is incised and carefully debulked in four quadrants, exposing the bare, intact Descemet's membrane.
Donor Button Preparation & Placement: The donor corneal graft is prepared by stripping off its endothelial layer and Descemet's membrane, sized to match the host bed, and positioned over the host Descemet's membrane.
Microsurgical Suturing: The donor button is secured to the host rim using 16 interrupted 10-0 nylon sutures or a combined running-and-interrupted pattern, adjusted with a surgical keratometer to minimize post-operative astigmatism.
Postoperative monitoring ensures stability before same-day discharge or short overnight stay:
Application of topical antibiotic and corticosteroid ointment, followed by placement of a sterile eye pad and a rigid protective eye shield.
Monitoring in the recovery area for 1 to 2 hours until sedation wears off, vital signs are stable, and comfort is established.
Slit-lamp examination before discharge to confirm graft apposition, anterior chamber depth, and absence of interface fluid.
Detailed post-operative counselling regarding eye drop schedules, shield wear, hygiene, and emergency warning signs.
Partial Trephination and Big-Bubble Formation
A partial-thickness circular trephination is made, followed by deep stromal air injection to achieve pneumodissection.
Big-Bubble Pneumodissection: A 27G/30G needle or cannula is guided into the deep posterior stroma to inject air, creating a bubble that detaches the stroma from Descemet's membrane.
Stromal Debulking: The anterior stroma is sectioned into quadrants and excised, revealing a smooth, pristine Descemet's membrane.
Step 3
Step 3
Graft Placement and Alignment
The prepared donor stromal button is sized to match the host bed and placed onto the bare host Descemet's membrane.
Graft Trephination: The donor stromal disc is punched to the exact diameter (often matching or 0.25 mm larger than host trephine).
Interface Irrigation: The interface between the host Descemet's membrane and donor stroma is gently irrigated to ensure no debris or air bubbles are trapped.
Step 4
Step 4
Suturing and Keratometric Adjustment
The donor graft is secured to the host cornea with microscopic 10-0 nylon sutures to restore normal corneal curvature.
Suturing: Secured with 16 interrupted 10-0 nylon sutures or a combined continuous-interrupted suture pattern.
Astigmatism Control: An intraoperative qualitative keratometer is used to check circularity and adjust suture tension, minimizing post-operative astigmatism.
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Minimised by precise intraoperative keratometry and managed post-operatively with selective suture removal, suture adjustment, spectacles, or specialty contact lenses.
Stromal or Epithelial Graft Rejection
Low (~2% to 5%; significantly lower than PK; endothelial rejection is eliminated)
Immune-mediated inflammatory reaction against donor stromal keratocytes or epithelium, presenting with redness, haze, or circumcorneal injection.
Monitored closely at follow-up visits; promptly reversible with a temporary course of intensive topical corticosteroid eye drops.
Infection (Microbial Keratitis / Endophthalmitis)
Rare (less than 0.5%)
Bacterial, fungal, or viral infection at the suture tracts, graft-host junction, or within the intraocular cavity.
Prevented by strict sterile technique, povidone-iodine antisepsis, donor tissue screening, and post-operative prophylactic antibiotic drops.
Suture-Related Complications (Loose or Broken Sutures)
Occasional over 12–18 months
Loosening, breakage, or neovascularisation along 10-0 nylon sutures, which can induce astigmatism or increase infection risk if left unaddressed.
Regular slit-lamp monitoring; loose or vascularised sutures are promptly removed in the clinic under topical anaesthesia.
Post-surgical care before discharge focuses on patient comfort, graft verification, and aftercare education:
Application of a sterile eye pad and rigid eye shield over the operated eye to protect against accidental pressure.
Review of written medication schedules, including topical antibiotic and corticosteroid eye drop regimens.
Confirmation of your first post-operative follow-up appointment (typically scheduled for the next morning).
Eye Care
Instil prescribed antibiotic and corticosteroid drops exactly as directed. Never stop or reduce steroid drops without consulting your surgeon.
Strictly avoid rubbing, pressing, or touching the operated eye at all times to prevent suture loosening or wound dehiscence.
Wear the protective rigid eye shield while sleeping or napping for at least 4 to 6 weeks.
Hygiene & Activity
Keep tap water, soap, and shampoo away from the operated eye for 2 to 3 weeks; clean the face with a damp washcloth.
Avoid dusty, smoky, or dirty environments; wear sunglasses outdoors for light sensitivity and wind protection.
Avoid bending below the waist, heavy lifting (>5 kg), straining, and vigorous exercise for 3 to 4 weeks.
Activity Guide
Permitted: Light walking, reading, watching television, and computer use as comfort permits from the first few days.
Return to Work: Typically within 2 to 3 weeks for desk-based work; 6 to 8 weeks for physically demanding or dusty occupations.
Prohibited: Swimming, hot tubs, contact sports, and vigorous gym workouts until cleared by your surgeon (usually 3 to 6 months).
DALK is ideal for advanced keratoconus, corneal ectasia, and stromal scars provided the endothelium is healthy. If the endothelium has been damaged (e.g., from severe chronic hydrops or concurrent endothelial dystrophy), a full-thickness transplant or endothelial keratoplasty is more appropriate.
What happens if the surgery needs to be converted to a full-thickness transplant?
If a large tear (macroperforation) occurs in Descemet's membrane during stromal dissection, the surgeon may convert the procedure to a standard Penetrating Keratoplasty (PK) in the same session. This is a planned intraoperative safety decision rather than a surgical failure.
How long does DALK surgery take?
DALK surgery typically takes 60 to 120 minutes depending on anatomical complexity, stromal adherence, and the dissection technique employed.
How long will I stay in the hospital?
Most DALK procedures are performed on a day-care basis with discharge after 1 to 2 hours of post-operative observation. Some patients may have a short overnight stay depending on systemic health, anaesthetic recovery, or local hospital protocol.
How long do the stitches stay in after DALK?
Corneal sutures typically remain in place for 10 to 18 months. Individual tight sutures causing astigmatism can be selectively adjusted or removed in the clinic starting 3 to 6 months after surgery, while complete suture removal is individualized based on healing.
Is graft rejection still possible with DALK?
Endothelial rejection—the most common cause of full-thickness graft failure—cannot occur because your own endothelial cells are preserved. However, stromal or epithelial rejection can still occur in approximately 2% to 5% of cases, which is typically mild and promptly treated with corticosteroid drops.
When can I return to normal activities after DALK?
Light daily activities and desk work can usually be resumed within 2 to 3 weeks. Strenuous exercise, heavy lifting, swimming, and contact sports should be avoided for 3 to 6 months or until approved by your surgeon.
Will my vision be completely normal after DALK?
Most patients achieve substantial visual improvement. However, high-order aberrations and astigmatism are common while sutures are in place. Final vision is optimized with spectacles or specialty contact lenses once the graft has stabilized.
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Australian Corneal Graft Registry - Long-Term DALK vs PK Outcomes
Demonstrated significantly lower graft rejection rates and superior long-term survival in DALK compared to PK in eyes with keratoconus.
Established anterior lamellar keratoplasty as the preferred clinical standard over full-thickness transplantation for stromal diseases with preserved endothelium.