Descemet membrane endothelial keratoplasty

Descemet Membrane Endothelial Keratoplasty (DMEK) is a surgical procedure in the field of ophthalmology that involves the transplantation of the endothelial layer of the cornea. This procedure is specifically designed to treat diseases affecting the endothelial layer, such as Fuchs' dystrophy and pseudophakic bullous keratopathy. DMEK offers significant advantages over traditional corneal transplantation techniques, including faster visual recovery and reduced risk of graft rejection.

Overview

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The endothelial layer is the innermost layer of the cornea, responsible for maintaining corneal transparency by pumping excess water out of the tissue. When the endothelial cells are damaged or diseased, they do not regenerate, leading to corneal edema and vision loss. DMEK selectively replaces the diseased endothelial layer, leaving the rest of the cornea intact.

Indications

DMEK is primarily indicated for conditions that affect the endothelial layer of the cornea, including:

• Fuchs' dystrophy: A progressive, degenerative disease that leads to the deterioration of endothelial cells.
• Pseudophakic bullous keratopathy: A condition that occurs as a complication of cataract surgery, leading to endothelial cell loss.
• Corneal endothelial dystrophy: A group of genetic conditions affecting the endothelial cells.

Procedure

The DMEK procedure involves the following steps:

1. Donor corneal preparation: A donor cornea is carefully prepared to isolate the Descemet membrane along with the endothelial cell layer.
2. Recipient eye preparation: The diseased endothelial layer is removed from the recipient's cornea.
3. Graft insertion: The donor endothelial layer is then inserted into the recipient's eye through a small incision.
4. Graft positioning: Once inside the eye, the graft is positioned correctly and attached to the recipient's cornea using an air bubble.

Advantages

DMEK offers several advantages over traditional corneal transplant techniques, such as Penetrating Keratoplasty (PK) and Descemet's Stripping Endothelial Keratoplasty (DSEK):

• Faster visual recovery: Patients often experience significant improvements in vision within weeks.
• Lower rejection rates: The selective transplantation of the endothelial layer reduces the risk of immune rejection.
• Better visual outcomes: DMEK can provide near-normal vision due to the replacement of only the diseased layer without altering the cornea's shape.

Risks and Complications

While DMEK is a safe procedure, it is not without risks. Complications may include:

• Graft failure: The transplanted endothelial layer may fail to function properly.
• Graft dislocation: The graft may shift from its original position, requiring repositioning.
• Air bubble complications: The air bubble used to attach the graft can cause increased intraocular pressure or damage to the iris.

Conclusion

Descemet Membrane Endothelial Keratoplasty represents a significant advancement in corneal transplantation, offering hope for patients with endothelial dysfunction. By focusing on the replacement of only the diseased layer, DMEK provides improved visual outcomes and a lower risk of complications compared to traditional methods.