ENDOTHELIAL KERATOPLASTY

ENDOTHELIAL KERATOPLASTY

November 03, 2021

Corneal transplantation is a widely practiced surgical procedure. Over the past decade, lamellar techniques have been developed to replace penetrating keratoplasty (PK).

Endothelial Keratoplasty (EK) has been adapted as an alternative in the treatment of corneal endothelial disorders.  

In the various forms of endokeratoplasty, Descemet’s membrane and the endothelium are replaced, with or without a varying amount of corneal stroma.

In Descemet’s stripping endothelial keratoplasty (DSEK), the patient’s Descemet membrane is peeled off, using specially designed strippers and replaced with a partial thickness graft: a transplanted disc of Posterior Stroma, Descemet and Endothelium (10-30 % of the inner donor cornea).

Both donor and host cornea are manually dissected. Differently, in Descemet’s stripping automated endothelial keratoplasty (DSAEK) the donor dissection is carried out using a mechanical microkeratome.

DSAEK is described as the procedure of choice for corneal endothelial failure in many centers.

Endothelial keratoplasty (EK) is a cornea transplant technique that is the preferred way to restore vision when the inner cell layer of the cornea stops working properly from Fuchs’ dystrophy, bullous keratopathy, iridocorneal endothelial (ICE) syndrome, or other endothelial disorders.

EK selectively replaces only the diseased layer of the cornea, leaving healthy areas intact.

With more than two decades since it was first described, endothelial keratoplasty (EK) has completely revolutionized the treatment of vision loss caused by corneal endothelial pathology.

Although more challenging compared to previous full-thickness penetrating keratoplasty (PK), the EK surgical techniques such as Descemet stripping endothelial keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK) have allowed for smaller incisions, greater safety, quicker recovery and better visual outcomes.

These key advantages have decreased the threshold for surgical intervention for corneal endothelial pathology when compared to conventional PK.

Since the early days of DSEK, we have seen an evolution to thinner grafts and less cumbersome donor tissue preparation techniques, which were greatly advanced with the introduction of the microkeratome.

The ultimate goal of thinner grafts and quicker visual recovery was greatly advanced again when DMEK was first described in 2006.

Compared to the adoption of DSEK from PK, DSEK to DMEK adoption has been slower, which is felt to be due to more difficult tissue preparation and a steeper learning curve for surgeons with this surgical technique.

On the international stage, utilization and adaptation of keratoplasty techniques have been restricted due to a shortage of donor cornea tissue.

Over the past decade, EK has made an impact by not only allowing for more targeted treatments of corneal pathology but also allowing for use of one corneal donor tissue to be utilized for multiple recipients.

For instance, the endothelium from one donor can be used for EK, while the stroma from the same donor can be utilized for deep anterior lamellar keratoplasty for another recipient.

This has been effective and impactful in low-resource settings of the developing world. Over the past 15 years, EK cases have grown to surpass PK cases. DSEK cases peaked around 2013, and the number of DMEK cases completed by US surgeons continues to increase each year.

In the future, we plan to see EK moving towards further development and improvement in the areas of endothelial graft survival, surgical techniques/tissue delivery and overall improvement of visual predictability.

Even with the potential introduction of biologic and pharmacologic treatments for endothelial pathology coming down the pipeline, EK is a surgical technique that is likely here to stay.