Pre-Descemet's endothelial keratoplasty

Pre-Descemet's Endothelial Keratoplasty (PDEK) is an advanced corneal transplantation technique that involves the selective replacement of the endothelium, the innermost layer of the cornea, along with a thin layer of stroma and Descemet's membrane. This surgical procedure is primarily used to treat corneal diseases that affect the endothelial layer, such as Fuchs' dystrophy and pseudophakic bullous keratopathy.

Overview

PDEK is a refinement of earlier endothelial keratoplasty techniques, such as Descemet's Stripping Endothelial Keratoplasty (DSEK) and Descemet's Membrane Endothelial Keratoplasty (DMEK). Compared to these methods, PDEK offers the advantage of transplanting a thinner layer of corneal tissue, which can lead to better visual outcomes and a reduced risk of graft rejection.

Indications

PDEK is indicated for patients with endothelial dysfunction, which can manifest as corneal edema, decreased vision, and pain. Common conditions treated with PDEK include:

• Fuchs' dystrophy
• Pseudophakic bullous keratopathy
• Corneal endothelial dystrophy
• Failed previous corneal grafts

Procedure

The PDEK procedure involves several key steps:

1. The surgeon prepares the donor corneal tissue by isolating a thin layer consisting of the endothelium, Descemet's membrane, and a small amount of posterior stroma.
2. The recipient's diseased endothelial layer is carefully removed.
3. The prepared donor tissue is then inserted into the recipient's eye through a small incision.
4. The graft is positioned and attached to the recipient's cornea using an air bubble to ensure adherence.

Advantages

PDEK offers several advantages over traditional full-thickness corneal transplantation and earlier forms of endothelial keratoplasty:

• Faster visual recovery
• Reduced risk of graft rejection
• Preservation of more corneal tissue
• Potentially better visual outcomes due to the transplantation of a thinner and more anatomically similar corneal layer

Risks and Complications

As with any surgical procedure, PDEK carries risks, including:

• Graft dislocation or detachment
• Graft failure
• Infection
• Eye pressure increase (glaucoma)
• Rejection of the donor tissue

Postoperative Care

After PDEK, patients typically require several months of follow-up care, which includes the use of topical steroids to reduce inflammation and prevent graft rejection, as well as other medications to manage eye pressure and promote healing.

Conclusion

Pre-Descemet's Endothelial Keratoplasty represents a significant advancement in the field of corneal transplantation, offering hope for patients with endothelial dysfunction. By providing a less invasive option with the potential for better visual outcomes, PDEK has become an important tool in the treatment of corneal diseases.