Corneal transplant vs amniotic membrane graft: A complete medical guide

Vision disorders affect hundreds of millions of people worldwide, with more than 2.2 billion individuals living with some form of visual impairment according to the World Health Organization. In response to this major global health challenge, modern ophthalmology has made significant progress, particularly through corneal transplantation and amniotic membrane transplantation (AMT). These two surgical techniques now provide effective solutions for restoring or preserving sight.

In this guide, we explain in clear, accessible terms how these procedures work, when they are indicated, and what clinical outcomes patients can expect. We also explore why Turkey has emerged as a leading destination for high-quality, affordable ophthalmic care.

The role of the cornea in vision

The cornea is the transparent, dome-shaped surface that covers the front of the eye. It is responsible for 65 to 75% of the eye's total refractive power, making it the primary focusing structure of the visual system. When healthy, it bends incoming light precisely onto the retina for sharp, clear vision.

Various diseases can compromise corneal clarity or structure: keratoconus (progressive thinning), Fuchs' endothelial dystrophy (dysfunction of the inner cell layer), infectious scarring (herpes simplex, bacteria), trauma, or chemical burns. When spectacles, rigid contact lenses, or medical therapy are insufficient, surgical intervention is considered.

Two major surgical strategies exist: keratoplasty (corneal transplant) and amniotic membrane transplantation (AMT). Their indications, mechanisms of action, and risk profiles differ fundamentally.

Corneal transplant procedures (keratoplasty)

Keratoplasty replaces all or part of a diseased cornea with healthy donor tissue. Techniques have evolved towards increasingly selective, layer-specific grafts, which reduces rejection risk and improves visual outcomes.

Penetrating keratoplasty (PK) — full-thickness graft

PK is the historical technique: the surgeon removes the full central thickness of the cornea and replaces it with a sutured full-thickness graft. Although well-established, it carries a longer recovery (12–18 months), a higher rejection risk, and suture-induced irregular astigmatism.
A 2019 meta-analysis published in Ophthalmology reported a 5-year graft survival rate of 72% for PK, compared to over 85% for modern lamellar techniques. PK remains indicated when multiple corneal layers are simultaneously affected.

Lamellar keratoplasty — targeted partial grafts

Lamellar techniques replace only the diseased corneal layer while preserving healthy layers. This approach significantly reduces rejection risk — the endothelium–Descemet complex is the primary trigger of immune response — and shortens recovery.

DSAEK — Descemet's Stripping Automated Endothelial Keratoplasty

DSAEK replaces the endothelium and a thin posterior stromal layer with a graft approximately 100–150 µm thick. Tissue is inserted through a small incision (3–4 mm) and fixed with an air bubble. Stable visual recovery is typically achieved in 3 to 6 months. A study published in Cornea (2020) reported a mean visual acuity gain of +0.3 LogMAR at 12 months.

DMEK — Descemet Membrane Endothelial Keratoplasty

DMEK is currently considered the gold standard for isolated endothelial conditions (Fuchs' dystrophy, bullous keratopathy). It transplants only the Descemet membrane and endothelium — a tissue layer less than 15 µm thick.

Data published in JAMA Ophthalmology (Price et al., 2021) show that 90% of DMEK patients achieve visual acuity ≥ 20/25 at 1 year, with a rejection rate below 1%. Visual recovery is faster than with DSAEK: functional acuity is often reached within 4 to 8 weeks.

DALK — Deep Anterior Lamellar Keratoplasty

DALK replaces the anterior stroma while preserving the patient's own endothelium. It is particularly indicated in advanced keratoconus and stromal scarring. By sparing the patient's endothelium, it virtually eliminates the risk of endothelial rejection — the leading cause of long-term graft failure.

Patient Story — Emilia, 34, Marseille “I was diagnosed with advanced bilateral keratoconus, and my ophthalmologist in France recommended a full-thickness corneal transplant with an 18-month waiting list. Through Turquie Santé, I underwent DALK surgery in Istanbul within just six weeks, with seamless coordination before and after my return. Six months later, I can read without lenses for the first time in ten years.”

Patient testimonial, 2025 — name changed with consent. Results may vary depending on individual medical conditions.

Main indications for corneal transplant

• Keratoconus (progressive corneal thinning)
• Fuchs' endothelial dystrophy
• Post-surgical bullous keratopathy
• Corneal scarring (herpes, trauma, deep burns)
• Corneal oedema refractory to medical treatment
• Failed previous graft

Amniotic membrane transplantation (AMT)

The amniotic membrane is the innermost layer of the human placenta. After rigorous screening (infection testing, processing, irradiation or cryopreservation), it is used as a surgical biomaterial on the ocular surface.

AMT is not a corneal transplant: it does not replace the corneal structure, but creates a biologically favourable environment for ocular surface repair. It is often used as a complement to, or preparation for, corneal transplantation.

Documented biological properties of amniotic membrane

• Anti-inflammatory action: suppression of pro-inflammatory cytokines (IL-1, TNF-α), beneficial in chemical burns and severe inflammation.
• Re-epithelialization support: the membrane acts as a substrate for epithelial cell migration; in vitro studies published in Investigative Ophthalmology & Visual Science show healing acceleration of 40 to 60% compared to conventional care.
• Anti-scarring activity: inhibition of myofibroblasts, reducing opacifying fibrous tissue formation.
• Analgesic effect: reduction of post-operative pain, sometimes within the first 48 hours.
• Antimicrobial properties: presence of peptides (defensins, elafin) active against certain bacteria and fungi.

Because amniotic membrane is acellular after processing, the risk of immunological rejection is very low — a fundamental distinction from corneal grafts, where long-term local immunosuppression is essential.

Main indications for AMT

• Chemical or thermal eye burns (urgent indication)
• Persistent epithelial defects resistant to conventional treatment
• Refractory corneal ulcers
• Limbal stem cell deficiency
• Severe dry eye disease (DEWS II stage III–IV)
• Recurrent pterygium
• Symblepharon (conjunctival adhesions)
• Ocular surface preparation before corneal transplant

 Comparison table: corneal transplant vs AMT

The table below summarises the main clinical differences between the two approaches to help physicians and patients identify the most appropriate strategy.