Advanced Corneal Transplant (PDEK)

In medical terms, graft refection is a very common mechanism. It occurs when the immune system of the recipient attacks the organ or the tissue of the receiver and slowly begins to destroy it. Fundamentally, the idea behind the mechanism of graft rejection is the presence of the donor’s own unique set of HLA proteins, which the recipient’s immune system recognises as alien, frequently triggers this immunological response.

On the other hand, histocompatibility refers to the degree of similarity between the recipient and the donor’s HLA genes. Simply put, the more genetically compatible the recipient and the donor are, the more tolerant the recipient’s immune system should be of the entire transplant process.

In organ/tissue transplants, there will always be some degree of rejection, unless the donor and the receiver are genetically identical, for example, in cases of identical twins.

In some situations, a patient may suffer from a graft versus host reaction, in which already matured immune cells present in the donor graft begin attacking the recipient’s healthy cells. Graft against host reaction, which occurs when the donor graft is classified as “immune-competent” (i.e., capable of eliciting an immunological response), is a risk associated with bone marrow transplants or stem cell transplants. In addition, it can also occur after blood transfusions.

Penetrating keratoplasty is an outpatient procedure, which means that patients can return home the same day. The majority of patients will have a post-operative appointment the next day.

Patients are given prescription eye drops to use in the weeks and months following a corneal transplant to aid in the healing process. Patients may experience blurry vision after the treatment while the eye adjusts to the new cornea. While recovery times differ, most patients report that their eyes heal, and their eyesight improves within a few months of surgery.

It is critical to safeguard the eye as much as possible in the days following the treatment. During this time, your doctor may advise you to wear a protective shield.

Although the corneal replacement may have been executed successfully and is working as well as it can, various eye disorders may affect the quality of a person’s eyesight after the corneal replacement surgery.

To improve vision, the new cornea may carry some level of astigmatism, which in many cases, requires special contacts or glasses. Other eye illnesses including glaucoma, diabetic retinopathy, or macular degeneration might reduce the patient’s vision quality and restrict them from seeing 20/20.

 You will have to go through the following procedures before your cornea or eye transplant surgery:

• A comprehensive eye examination is required. Your eye doctor thoroughly examines you for any eye diseases or conditions that could lead to complications or issues following the eye transplant surgery.
• Your eye’s measurements. The concerned ophthalmologist will determine the exact size of the cornea that you’ll require in the eye transplant surgery.
• A close review of all of the drugs and supplements you’re consuming. Before or after your cornea/eye transplant, you may need to stop using certain drugs or supplements.

Once the penetrating keratoplasty surgery is successful, you may drive after the anaesthesia has come off and the vision in the other eye is completely fit for driving. 

It could take up to 24 hours for this to happen. However, it’s possible that your surgeon will advise you to wait a few days before stepping behind the wheel. Remember that you’ll need someone to drive you home from the hospital and drive you back the next day for your follow-up appointment.

Corneal endothelial rejection is the most common type of corneal transplant rejection, an immune response where the host’s body attacks the donor’s endothelial cells, leading to cloudy vision, redness, light sensitivity, pain, and graft swelling. Prompt, aggressive treatment with corticosteroids is crucial to prevent permanent graft failure, as these cells don’t regenerate well.

PDEK is the acronym for Pre-Descemet’s Endothelial Keratoplasty, where we remove the diseased Descemet’s membrane and endothelium from the patient and replace it with a healthy Dua’s–Descemet’s membrane-Endothelium complex from a donated eye. This procedure has an accelerated recovery time and reduced risk of complications associated with traditional full-thickness corneal transplantation.

Dua’s layer, or the pre-Descemet’s layer, is the newly identified sixth layer of the cornea. This ultra-thin, strong, and acellular layer (about 10-15 microns thick) provides significant mechanical strength to the cornea. In PDEK, we remove the diseased Descemet’s membrane-Endothelium complex from the patient, leaving behind the Dua’s layer, and replace it with a healthy Dua’s Descemet’s membrane-Endothelium complex from a donated eye. This provides excellent attachment of the graft in the patient’s eye.

Replacing only one thin layer of the cornea is better for patients because it has faster recovery times, a lesser risk of complications associated with conventional full-thickness corneal transplants and reduced risk of multilayered corneal rejection.

Patients suffering from corneal endothelial dysfunction seen in Fuch’s Endothelial Dystrophy, decompensated cornea after cataract surgery, Congenital Hereditary Endothelial Dystrophy, ICE syndrome, and pediatric patients all benefit from PDEK surgery.

Return to work after PDEK surgery depends on your job type and how quickly you recover. For desk or office work, most people can resume within 1–2 weeks once vision begins to stabilize. Light daily activities can be done within a few days to 1 week. If your job involves physical effort or dusty environments, it’s safer to wait 3–4 weeks or more. Driving should only be resumed after your doctor confirms your vision is adequate, usually around 2 weeks. Since PDEK involves a delicate endothelial graft, the first week is crucial proper head positioning and avoiding strain are important. Vision typically improves over 2–4 weeks, though full stabilization may take longer.

After PDEK surgery, medications are gradually tapered rather than stopped suddenly. Typically, steroid eye drops are used intensively in the first week (hourly to every 2 hours), then slowly reduced and continued for 6–12 months or longer, with some patients needing a low-dose daily maintenance to prevent graft rejection. Antibiotic drops are usually prescribed for 1–2 weeks, while lubricating drops may be needed for several weeks to months depending on comfort. If required, anti-glaucoma drops may be used either short-term or long-term based on eye pressure. Among all medications, steroids are the most critical for preventing graft rejection. The exact duration varies depending on healing, graft clarity, and eye pressure, so regular follow-ups are essential for proper tapering.