What is PDEK?
PDEK (Pre-Descemet’s Endothelial Keratoplasty) is an advanced corneal transplant technique that replaces the damaged inner layer of the cornea with healthy donor tissue. It allows faster healing, better visual recovery, and uses thinner graft tissue compared to traditional corneal transplant methods.
PDEK in India: Context That Matters
Modern corneal transplantation has moved steadily away from the blunt approach of replacing the entire cornea. Surgeons now ask a sharper question: which layer is actually sick, and can we replace only that one?
PDEK (Pre-Descemet’s Endothelial Keratoplasty) is an answer to that question. It is a selective lamellar transplant in which only the innermost layers of the cornea are replaced: Dua’s layer (also called the pre-Descemet’s layer), Descemet’s membrane, and the endothelium. The patient’s own stroma and epithelium stay intact.
The corneal endothelium is a single layer of cells lining the back surface of the cornea. These cells work like tiny pumps, moving water out of the cornea to keep it clear. When they fail (Fuchs’ dystrophy, bullous keratopathy after cataract surgery, failure of a previous graft), the cornea swells, clouds, and eventually starts to hurt. Traditional full-thickness transplantation solved the clarity problem but brought its own baggage: sutures, irregular astigmatism, slow recovery, and a meaningful risk of graft rejection. PDEK rewrites that trade-off.
The technique was pioneered by Dr Harminder Singh Dua and colleagues, and it builds on the earlier DSEK and DMEK approaches. Vasan Eye Care’s cornea specialists are trained in endothelial keratoplasty including PDEK for patients with endothelial disease.
Endothelial keratoplasty has changed the face of corneal surgery globally, and that change has reached Indian clinics too. For conditions like Fuchs’ dystrophy, the older penetrating keratoplasty has largely given way to DSEK, DMEK, and PDEK, with good reason: faster recovery, lower rejection risk, and preservation of the eye’s structural integrity.
India also has a massive unmet need. Corneal blindness is estimated to affect around 6.8 million people, and donor corneal tissue is chronically scarce. This is where a specific feature of PDEK matters more here than almost anywhere else: a single donor cornea can potentially yield two PDEK grafts, one from each half of the Descemet’s membrane. In a country with a donor tissue shortage, that efficiency is not a nice-to-have. It is a real contribution to the supply problem.
Types of Endothelial Keratoplasty
| Procedure | Layers Transplanted | Key Feature |
|---|---|---|
| DSEK / DSAEK | Stroma + Descemet’s + Endothelium | Widely available; thicker graft; faster than PK |
| DMEK | Descemet’s + Endothelium only | Thinnest graft; fastest visual recovery; technically demanding |
| PDEK | Pre-Descemet’s + Descemet’s + Endothelium | Easier to handle than DMEK; faster recovery than DSEK |
| UT-DSAEK | Very thin posterior stroma + Descemet’s + Endothelium | Intermediate between DSEK and DMEK |
How the Procedure Works?
PDEK is performed under topical or peribulbar anaesthesia as a day-case procedure. The clever bit is the big bubble technique developed by Dr Dua. Air is injected into the donor corneal stroma and finds a natural tissue plane, creating a self-limiting “type 1 big bubble.” This cleanly separates a graft that includes Dua’s layer, Descemet’s membrane, and the endothelium as a single cohesive unit.
That extra layer matters practically. A DMEK graft, made of just Descemet’s and endothelium, is notoriously floppy and hard to handle in the anterior chamber. The PDEK graft is a touch sturdier. It unfolds more predictably.
In the recipient eye, the diseased Descemet’s membrane and endothelium are stripped off through a small corneal incision (Descemetorhexis). The prepared PDEK graft is loaded into an injector and delivered through the small incision into the anterior chamber. A gas bubble (air or SF6) is injected beneath the graft to press it up against the recipient’s posterior stromal surface, where it adheres within hours. The patient lies face-up for the first hour to keep the bubble centred. No sutures are needed for the graft itself.
When Is PDEK Indicated?
- Fuchs’ endothelial corneal dystrophy, with clouding, glare, and blurred vision that is often worst in the morning
- Bullous keratopathy: corneal swelling and blistering from endothelial failure after cataract surgery, glaucoma surgery, or trauma
- Failed previous corneal grafts with endothelial failure (primary or secondary graft failure)
- Posterior polymorphous corneal dystrophy (PPCD) with significant endothelial dysfunction
- Iridocorneal endothelial (ICE) syndrome with progressive endothelial cell loss
- PDEK is appropriate when the patient’s corneal stroma is still clear or near-clear. If the stroma is significantly scarred, a deeper lamellar or full-thickness graft may be the better tool.
Step-by-Step Procedure
- Pre-operative evaluation: specular microscopy (endothelial cell count), corneal topography, pachymetry, anterior segment OCT, anterior chamber depth assessment.
- Donor tissue preparation: big bubble technique using air injection to isolate the pre-Descemet’s, Descemet’s, and endothelium graft from the donor corneoscleral button.
- Recipient preparation: a small (3 to 3.5 mm) clear corneal incision, followed by Descemetorhexis to strip the recipient’s diseased Descemet’s and endothelium.
- Graft delivery: the PDEK graft is loaded into an injector and introduced into the anterior chamber through the small incision.
- Graft unfolding: using fluid manoeuvres, the graft is oriented correctly (endothelium facing down) and centred over the posterior stroma.
- Air bubble injection: air or SF6 gas is injected to press the graft against the recipient stroma and start the adhesion process.
- Post-operative positioning: the patient lies face-up for at least an hour to keep the bubble in contact with the graft.
How Much Does PDEK Cost in India?
| Procedure | Approximate Cost Range (INR) |
|---|---|
| PDEK (primary endothelial keratoplasty) | 60,000 to 1,40,000 |
| PDEK combined with cataract surgery | 80,000 to 1,80,000 |
| DSEK / DSAEK (for comparison) | 50,000 to 1,20,000 |
| DMEK (for comparison) | 70,000 to 1,50,000 |
Costs include donor tissue, surgical facility, and surgeon fees. Donor tissue availability affects scheduling. Contact Vasan Eye Care for current availability and pricing.
Post-Surgery Care and Recovery
What to Expect After PDEK?
PDEK delivers faster visual recovery than traditional full-thickness corneal transplantation. Most patients notice vision improvement within two to four weeks, with continued refinement over three to six months as the transplanted endothelium settles and the cornea clears. Final vision can be very good, because the patient’s own optical surface (epithelium and stroma) has been preserved. You are essentially getting your own clear cornea back, with a new functional layer on the inside.
A small proportion of PDEK grafts do not adhere fully on the first attempt and need rebubbling: a fresh air bubble injected under the graft to coax it back into contact. This is a minor procedure at the slit lamp under topical anaesthesia. Graft rejection, while less common than with penetrating keratoplasty, does happen and is managed with intensive topical steroid drops. Catching rejection early is the whole point of long-term follow-up.
Post-Operative Care Tips
- Lie flat (face-up) for the first one to two hours after surgery, and avoid bending forward. This keeps the air bubble against the graft.
- Use steroid drops exactly as prescribed. Long-term steroid use, often for a year or more, is standard to prevent rejection.
- Attend follow-up visits at day 1, week 1, month 1, and every three months after that.
- Do not rub the eye. The graft is delicate while it is adhering in the first weeks.
- Report sudden vision loss, pain, or redness immediately. These can signal rejection or graft displacement.
- Specular microscopy at follow-up visits tracks the health of the transplanted endothelial cells over time.
References
PMC / NCBI. Pre-Descemet’s Endothelial Keratoplasty: A Review, 2019.
EyeWiki (AAO). Endothelial Keratoplasty.
American Academy of Ophthalmology. Corneal Transplant Surgery.
Frequently Asked Questions
Dua’s layer (the pre-Descemet’s layer) is a distinct, acellular layer sitting between the corneal stroma and Descemet’s membrane, described by Professor Harminder Dua. PDEK includes this layer with the graft, alongside Descemet’s membrane and the endothelium. That makes the PDEK graft slightly thicker and easier to handle than a pure DMEK graft, which has only Descemet’s and endothelium. You get most of the optical benefits of DMEK with less of the handling difficulty.
PDEK grafts are thinner than DSEK grafts, which preserves more anterior chamber space and is associated with faster visual recovery and potentially better final acuity. That said, PDEK is technically more demanding to prepare and deliver. “Better” is the wrong question. The right question is which technique fits the patient, the tissue, and the surgeon’s experience.
PDEK grafts can last many years. Transplanted endothelial cells decline in number over time (that is just biology), but provided the initial cell count was adequate and rejection episodes are treated promptly, grafts often remain functional for a decade or more. Long-term survival data for PDEK specifically is still being collected, because the technique is relatively new compared to older methods.
Rejection happens when the immune system recognises the transplanted tissue as foreign and mounts an inflammatory response against it. Endothelial rejection presents as sudden blurring, redness, and pain. It is treated with intensive topical steroids, sometimes combined with systemic steroids. Caught early, most rejection episodes can be reversed without permanent graft failure. This is exactly why patients cannot ignore “minor” symptoms in the post-operative years.
Yes. In patients with both cataract and endothelial disease (very common in Fuchs’ dystrophy), PDEK can be done alongside phacoemulsification in a single combined operation, sometimes called a “triple procedure.” One surgery, one recovery, one anaesthetic. It is efficient, and it avoids operating on the same eye twice in a short span.
Because PDEK preserves your own corneal stroma and surface, induced astigmatism is minimal and vision can be very good with spectacle correction. The final prescription is set once the cornea has stabilised, typically around six months. Pre-existing myopia or hyperopia will still need correction in glasses or contact lenses, because the PDEK itself does not change those.
Failure may be primary (the graft never takes, usually because the donor endothelial cell density was inadequate) or late (from irreversible rejection). A second PDEK or an alternative endothelial keratoplasty can be performed once the eye has recovered. Regraft surgery is more complex than the original, but it is achievable and often successful.
Usually not. Most PDEK procedures are done under peribulbar block or topical anaesthesia as a day case. General anaesthesia is reserved for anxious patients or those unable to cooperate with local anaesthesia.
Donor corneal tissue is procured by eye banks from consented deceased donors. India has a network of eye banks, but supply still falls short of demand. Waiting times vary by region and urgency. Vasan Eye Care works with accredited eye banks for tissue procurement.
Yes. Vasan Eye Care’s cornea surgical team performs endothelial keratoplasty procedures including PDEK for patients with Fuchs’ dystrophy, bullous keratopathy, and other endothelial corneal diseases.
References
PMC / NCBI. Pre-Descemet’s Endothelial Keratoplasty: A Review, 2019.
EyeWiki (AAO). Endothelial Keratoplasty.
American Academy of Ophthalmology. Corneal Transplant Surgery.
