Fuchs’ endothelial dystrophy: Taking a step back to go forward

Rotterdam, Netherlands-The future of treating Fuchs’ endothelial dystrophy may be evolving, said Gerrit R.J. Melles, MD, PhD.

“Perhaps we should take a step back to determine what we are actually treating,” said Dr. Melles, director, Netherlands Institute for Innovative Ocular Surgery, Rotterdam. “Does Fuchs endothelial dystrophy actually exist? Is it an actual dystrophy or is it something else?”

If the disorder is not a dystrophy and can be reversed, this may open the door to a different treatment, he suggested.

Descemet’s membrane endothelial keratoplasty (DMEK)-the procedure in which the inner corneal layer is replaced by donor Descemet’s membrane and endothelial tissue-and Descemet’s membrane endothelial transfer (DMET), in which donor Descemet’s membrane and endothelium are brought into the anterior chamber and clearing of the host cornea is awaited (the donor tissue is not in contact with the host cornea), are the two most recent procedures used to treat Fuchs endothelial dystrophy.

Dr. Melles enumerated the major factors when performing DMEK:

·      First, dissecting the trabecular meshwork with Descemet’s membrane makes stripping it much easier. This is accomplished by starting in the periphery and removing the trabecular meshwork with Descemet’s membrane.

·      Second, the best visualization is achieved by performing the surgery “under air,” he said, rather than balanced saline solution (BSS) and overhydration is avoided.

·      Third, the key factor to simplifying DMEK is to procure a double roll of donor tissue before insertion into the anterior chamber by irrigating Descemet’s membrane with BSS a few times and allowing it to fold back as a double roll.

·      Fourth, the correct orientation of the tissue roll must be ascertained.

·      Fifth, the donor tissue should be unrolled with an air bubble in the anterior chamber over the iris and inward tissue rolls in the periphery avoided.

Many surgeons are switching from Descemet’s stripping endothelial keratoplasty (DSAEK) because of the high best-corrected visual acuities (BCVAs) achieved with DMEK: 6 months postoperatively, 80% of patients have a BCVA of 20/25 or better after DMEK and further improved with a contact lens.

Patients with poor BCVA after DSAEK can achieve high visual acuity after a subsequent DMEK, while the refractive stability is stable after DMEK.

Potential complications of DMEK can be a decreased endothelial cell count, early graft detachment, secondary glaucoma, iatrogenic cataract, and allograft rejection.

The DMET procedure, however, may be the future of treating Fuchs’ endothelial dystrophy.

Dr. Melles explained that in these patients, the corneas began clearing 3 months after DMET and the cornea was “fairly normal” after 6 months. However, he said this approach does not work in patients with bullous keratopathy.

“This spontaneous corneal clearing suggests that the host cells must be involved somehow in the corneal clearing or redistribution of the endothelial cells postoperatively,” he said.

This then raises the question about what actually is being treated.

“Are we really treating a dystrophy or are we treating something else that possibly can be managed another way? Is a topical drop a possible therapy?” Dr. Melles said.

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