DSEK may be viable for patients with partial or complete aniridia

Further surgical technique modifications are needed as the indications for DSEK expand.

Anthony J. Aldave

Descemet’s stripping endothelial keratoplasty may be an option for eyes with partial or complete aniridia, a study found.

The study authors sought to expand the indications for DSEK and encourage others who have performed this procedure on nontraditional candidates to share their tips and techniques, first author Anthony J. Aldave, MD, told Ocular Surgery News.

“Corneal surgeons should consider performing DSEK in the setting of previous penetrating keratoplasty, partial or complete aniridia, or previous glaucoma surgery,” Dr. Aldave said. “A lot of surgeons in such situations, especially if there is a combination of these factors, would consider DSEK technically difficult to perform and would therefore proceed with a full-thickness instead of a partial-thickness transplant.”

The retrospective, interventional, consecutive case series reviewed medical records of four patients who underwent DSEK following Ophtec 311 iris reconstruction lens implantation.

Dr. Aldave has also recently reported an analysis of the results of DSEK in 56 eyes with previous tube shunt implantation, trabeculectomy or both in an article currently in press in Cornea. The study found that postoperative complications such as donor dislocation, primary graft failure and endothelial rejection do not occur at higher rates following DSEK in eyes with previous glaucoma surgery.

“DSEK is a better procedure than a full-thickness transplant, especially in a glaucoma population, because of the avoidance of inducing a neurotrophic keratopathy by performing full-thickness corneal trephination,” he said.

DSEK surgical modifications

While DSEK was successfully performed in eyes with partial or complete aniridia, the iris reconstruction lens study also showed that modifications to traditional surgical techniques might increase the likelihood of success and decrease the risk of donor cornea dislocation.

“Most of the modifications that we describe in the article are required due to the fact that in partial or complete aniridia, you do not have normal compartmentalization of the eye in the anterior and posterior chambers,” Dr. Aldave said.

According to the study authors, three modifications facilitate the performance of DSEK in such cases. The first is the use of an anterior chamber maintainer or an air fill of the anterior chamber prior to Descemet’s membrane stripping in the setting of an incomplete iris-lens-zonule barrier rather than the use of a viscoelastic. In such eyes, the viscoelastic would likely pass posteriorly into the vitreous cavity, leading to inadequate pressurization of the anterior chamber and difficulty scoring Descemet’s membrane, as well as retained viscoelastic, increasing the risk of donor dislocation and late IOP spikes.

Patient with partial aniridia and corneal edema following implantation of Ophtec 311 iris reconstruction lens.

Two and a half years after DSEK, the cornea remains clear and corrected distance visual acuity is 20/40. Images: Aldave AJ

The second technique modification involves injecting air beneath the donor button before unfolding it inside the eye.

“It behooves the surgeon to put an air bubble beneath the donor cornea before unfolding to protect the endothelium in the setting of an iris reconstruction lens and to prevent it from falling backward in an aphakic or aniridic eye,” Dr. Aldave said.

The third technique modification that the authors recommend in the setting of partial or complete aniridia or aphakia is to suture fixate the donor cornea to the host cornea while the anterior chamber is filled with air to prevent postoperative dislocation of the graft into the vitreous cavity.

In addition to these technique modifications, the study authors noted that in eyes with partial or complete aniridia, the anterior chamber may remain filled with air at the end of the surgery because pupillary block is not a concern. However, some air should be removed at the procedure’s conclusion to normalize the IOP level and minimize the risk of pressure-induced optic nerve damage.

Results, secondary graft failure

Of the four patients who underwent DSEK following iris reconstruction lens implantation, all had a history of glaucoma and two had undergone prior glaucoma surgery. In addition, prior PK had been performed in three of the four eyes.

Corrected distance visual acuity improved significantly in each eye during the mean follow-up period of 15.6 months, although the improvement was limited in two eyes by irregular corneal astigmatism and advanced glaucomatous optic neuropathy. None of the eyes developed donor dislocation or primary graft failure.

However, in two of the three eyes with a history of endothelial rejection following PK, recurrent graft rejection developed during follow-up. Subsequent secondary graft failure occurred in these eyes, as well as in the third eye with a history of a previous failed PK.

According to Dr. Aldave, these results raise the question as to whether eyes with a history of prior endothelial rejection and failure following PK should undergo keratoprosthesis implantation instead of DSEK. However, he added that the study’s sample size was small and that further research should be undertaken.

“Until we have the answer, I think DSEK is the way to go, because it is a safer surgery than keratoprosthesis. However, if a significant percentage of the endothelial keratoplasties performed after penetrating keratoplasty also fail secondary to endothelial rejection, then I think that we should be considering keratoprosthesis surgery for these patients.” – by Michelle Pagnani

Reference:

• Aldave AJ, Baghdasaryan E, Miller KM. Descemet stripping endothelial keratoplasty after Ophtec 311 iris reconstruction lens implantation. Cornea. 2011;30(4):405-408.

• Anthony J. Aldave, MD, can be reached at the Jules Stein Eye Institute, 100 Stein Plaza, UCLA, Los Angeles, CA 90095; 310-825-2737; email: aldave@jsei.ucla.edu.
• Disclosure: Dr. Aldave has no relevant financial disclosures.

Marianne O. Price

The take-home message is that DSEK can be a good option for restoring corneal clarity and may provide faster visual recovery than penetrating keratoplasty in eyes with an artificial iris due to partial or complete aniridia. Since the iris-lens-zonular barrier is incomplete in these eyes, appropriate precautions must be taken to prevent migration of recipient Descemet’s membrane, viscoelastic or the donor button into the posterior chamber. By placing an air bubble beneath the donor graft before releasing it, fixating the graft to the host cornea with a suture and not using any viscoelastic, DSEK was successfully completed in all study cases. Unfortunately, eyes with traumatic or congenital aniridia usually have significant comorbidity, which can limit visual acuity and increase the risk of secondary graft failure, as evidenced in this case series.

– Marianne O. Price, PhD
Executive Director, Cornea Research Foundation of America
Disclosure: Dr. Price receives travel grants from Moria.