Patterns of corneal endothelialization and corneal clearance after descemet membrane endothelial keratoplasty for fuchs endothelial dystrophy

Repeat Descemet membrane endothelial keratoplasty after complicated primary Descemet membrane endothelial keratoplasty

PURPOSE

To describe the clinical outcome and complications of repeat Descemet membrane endothelial keratoplasty (re-DMEK).

DESIGN

Retrospective case series study at a tertiary referral center.

PARTICIPANTS

From a series of 550 consecutive DMEK surgeries with ≥ 6 months follow-up, 17 eyes underwent re-DMEK for graft detachment after initial DMEK (n = 14) and/or endothelial graft failure (n = 3). The outcomes were compared with an age-matched control group of uncomplicated primary DMEK surgeries.

METHODS

The re-DMEK eyes were evaluated for best-corrected visual acuity (BCVA), densitometry, endothelial cell density (ECD), pachymetry, and intraoperative and postoperative complications.

MAIN OUTCOME MEASURES

Feasibility and clinical outcome of re-DMEK.

RESULTS

In all eyes, re-DMEK was uneventful. At 12 months, 12 of 14 eyes (86%) achieved a BCVA of ≥ 20/40 (≥ 0.5); 8 of 14 eyes (57%) achieved ≥ 20/25 (≥ 0.8), 3 of 14 eyes (21%) achieved ≥ 20/20 (≥ 1.0), and 1 eye (7%) achieved 20/17 (1.2); 5 eyes were fitted with a contact lens. Average donor ECD decreased from 2580 ± 173 cells/mm(2) before to 1390 ± 466 cells/mm(2) at 6 months after surgery, and pachymetry from 703 ± 126 μm to 515 ± 39 μm, respectively. No difference in densitometry could be detected between re-DMEK and control eyes (P = 0.99). Complications after re-DMEK included primary graft failure (n = 1), secondary graft failure (n = 2), graft detachment requiring rebubbling (n = 1), secondary glaucoma (n = 2), cataract (n = 1), and corneal ulcer (n = 1). One eye received tertiary DMEK.

CONCLUSIONS

In the management of persistent graft detachment and graft failure after primary DMEK, re-DMEK proved a feasible procedure. Acceptable BCVA may be achieved, albeit lower than after DMEK in virgin eyes, and some cases may benefit from contact lens fitting. Complications after re-DMEK may be better anticipated than after primary DMEK because graft detachment and graft failure tended to recur, suggesting that intrinsic properties of the host eye play a role in graft adherence and graft failure.

Incidental central tear in Descemet membrane endothelial complex during Descemet membrane endothelial keratoplasty

Descemet membrane endothelial keratoplasty (DMEK) was performed in a 70-year-old man diagnosed with pseudophakic bullous keratopathy. During Descemet endothelial complex (DEC) preparation, a central tear was noticed in the DMEK graft. However, the surgery was continued. On sixth postoperative day, a small fluid pocket was observed between the DEC and the posterior host stroma in inferior third of the graft area. It was, however, decided to observe it for spontaneous attachment. At 2 weeks, the inferior DEC detachment had increased with overlying corneal oedema. Descemetopexy with 100% air was performed the same day which reattached the DEC. Subsequently, DEC remained attached and at the last follow-up of 2 months, DEC was well opposed with a clear overlying cornea. The final best-corrected Snellen's visual acuity was 20/60. A small tear in the DEC does not necessitate tissue replacement and a good anatomical and visual outcome can be achieved in such cases.

Use of accidentally torn descemet membrane to successfully complete descemet membrane endothelial keratoplasty

PURPOSE

To describe the use of an accidentally torn Descemet membrane (DM) to successfully complete Descemet membrane endothelial keratoplasty (DMEK) surgery.

METHODS

Retrospective, observational case series of 3 eyes of 3 patients undergoing DMEK with a DM accidentally torn into 2 pieces during graft preparation. The mean outcome measures included best-corrected visual acuity, endothelial cell density, and central corneal thickness, before and at 1, 3, and 6 months after the DMEK surgery was performed.

RESULTS

During graft preparation, immediately before transplantation, a large tear within the 8.0-mm marking line of the DM occurred, resulting in a DM torn into 2 pieces. In all the eyes, both pieces were successfully implanted into the anterior chamber, unfolded and attached to the posterior corneal stroma, one after the other. Six months after the surgery was performed, the best-corrected visual acuity ranged between 20/30 and 20/25. Endothelial cell loss was about 30% (range 28%-32%) 6 months after the surgery. Pachymetry findings showed normal corneal thickness 6 months after the surgery. All corneas remained clear without any signs of graft failure within 6 months of follow-up.

CONCLUSIONS

DMEK surgery can be successfully completed despite the accidental tearing of donor DMs during the preparation of DMEK grafts by the sequential implantation of both DM pieces.

Potential causes of incomplete visual rehabilitation at 6 months postoperative after descemet membrane endothelial keratoplasty

PURPOSE

To determine the various causes of unexpected incomplete visual rehabilitation at 6 months postoperative after Descemet membrane endothelial keratoplasty (DMEK).

DESIGN

Retrospective study of prospectively collected data at a tertiary referral center.

METHODS

From a larger group of 400 consecutive DMEK surgeries, the last 200 consecutive eyes were reviewed for visual discomfort despite a best-corrected visual acuity (BCVA) of ≥20/25 (≥0.8) or unexpected subnormal BCVA (≤20/28; ≤0.7) at 6 months after DMEK. Biomicroscopy, funduscopy, Pentacam imaging, noncontact specular microscopy, anterior segment optical coherence tomography, and surgical videos were used to determine the causes of incomplete visual rehabilitation.

RESULTS

A total of 69 eyes out of 178 eyes that were included in the analysis (38.8%) presented with incomplete visual rehabilitation after DMEK, further categorized as "primarily patient-related" in 40 of 178 (22.5%), "primarily graft-related" in 21 of 178 (11.8%), and a combination of "patient-/graft-related" in 8 of 178 cases (4.5%). Unrecognized pre-existing ocular pathology and/or posterior segment disease in 19 of 178 eyes (10.7%), clinically significant corneal irregularities and/or central corneal scarring often secondary to long-standing preoperative corneal edema in 14 of 178 eyes (7.9%), or (partial) graft detachment in 20 of 178 eyes (11.2%) were the main causes of unexpected incomplete visual rehabilitation. Transient or persistent monocular ghost images or diplopia occurred in 10 of 178 eyes (5.6%), sometimes requiring contact lens fitting.

CONCLUSIONS

In contrast to earlier endothelial keratoplasty techniques that may frequently be associated with undefined transplant-related subnormal visual outcomes, incomplete visual rehabilitation after DMEK may virtually always be explained by concomitant ocular pathology or evident graft failure.

Descemet's membrane endothelial keratoplasty surgery: update on the evidence and hurdles to acceptance

PURPOSE OF REVIEW

Descemet's stripping endothelial keratoplasty (DSEK) is the most popular treatment for endothelial dysfunction, but Descemet's membrane endothelial keratoplasty (DMEK) now provides better vision with lower risk of immunologic rejection. Although DMEK is more challenging, advances in instrumentation and techniques are reducing the learning curve.

RECENT FINDINGS

In contrast to DSEK, which includes posterior donor stroma, DMEK consists merely of donor endothelium and Descemet's membrane, so DMEK does not create a stromal interface and induces significantly less posterior surface aberrations, resulting in better vision. Furthermore, multiple centers report remarkably low (<1%) cumulative probability of immunologic graft rejection episodes through 2 years after DMEK. Initially, the biggest challenges were tissue loss in preparation and ensuring attachment. Subsequent improvements have reduced complication rates to levels experienced with DSEK. DMEK/DSEK hybrids and 'thin' DSEK also can provide better vision than standard DSEK; randomized controlled comparisons with DMEK are needed.

SUMMARY

DMEK provides an anatomically exact replacement of dysfunctional host endothelium and has set new benchmarks for rejection risk and visual outcomes following endothelial replacement. DMEK is providing new insights into how different corneal layers contribute to immunogenicity and immune tolerance and into the key factors that limit vision after endothelial keratoplasty.

What does the future hold for the treatment of Fuchs endothelial dystrophy; will 'keratoplasty' still be a valid procedure?

Fuchs endothelial corneal dystrophy (FECD) is a well recognized corneal disorder characterized by the presence of collagenous warts extending from Descemet membrane (guttae) and endothelial cellular dysfunction due to cell loss and/or degeneration. Because of the characteristic abnormal cell morphology as seen with specular microscopy as well as the limited regenerative capacity in vivo, the endothelial cells were considered to be 'dystrophic'. Hence, FECD is commonly managed by replacement of the endothelium with donor tissue by means of a penetrating or endothelial keratoplasty. The latter procedure has now been refined to the isolated transplantation of a donor Descemet membrane and its endothelium, referred to as Descemet membrane endothelial keratoplasty (DMEK). Unexpectedly, clinical observation made after DMEK seemed to challenge the current concept of the state of the endothelium in FECD; we actually observed an important role for the 'dystrophic' host endothelium in re-endothelialization of the denuded DM, and subsequent corneal clearance. In addition, recent studies regarding the pathophysiology of FECD made us realize that the endothelial cells are not 'dystrophic' per se, but in the course of time may have acquired a dysfunction instead. This paper describes the rationale behind this new concept and based on this, discusses the possibilities for future, less invasive treatment modalities for FECD.

Predictive value of optical coherence tomography in graft attachment after Descemet's membrane endothelial keratoplasty

PURPOSE

To evaluate the predictive value of early anterior segment optical coherence tomography (AS-OCT) on graft adherence or detachment after Descemet's membrane endothelial keratoplasty (DMEK).

DESIGN

Retrospective study of prospectively collected data at a tertiary referral center.

PARTICIPANTS

A total of 87 eyes of 87 patients of a consecutive series of 142 DMEK surgeries.

METHODS

Anterior segment OCT was performed within the first hour after DMEK and at 1 week, 1 month, 3 months, and 6 months, and for each time interval detachments were classified as "none," ≤ 1/3 detachment, >1/3 detachment of the total graft surface area, or "complete" detachment. Throughout the study, no rebubbling procedures were performed.

MAIN OUTCOME MEASURES

Graft adherence at various postoperative time intervals.

RESULTS

One-hour AS-OCT scans were more accurate at predicting the final 6-month graft adherence status than those at 1 week or 1 month. Grafts showing complete attachment or <1/3 detachment at 1 hour remained stable or improved in 73% of the cases at 1 week, 82% at 1 month, 86% at 3 months, and 90% at 6 months. All grafts attached at 1 week remained attached at 6 months. Graft detachments of >1/3 at 1 hour showed reattachment at 6 months in 25% of the cases, whereas 67.5% of the cases showed a persistent detachment of >1/3 at 6 months and 12.5% showed a complete detachment.

CONCLUSIONS

The 1-hour AS-OCT scan showed the best predictive value on 6-month graft adherence status. The combined information of the 1-hour and 1-week AS-OCT scans may facilitate decision making about surgical reintervention after DMEK.

Recipient endothelium may relate to corneal clearance in descemet membrane endothelial transfer

PURPOSE

To describe corneal clearance after re-endothelialization of the recipient posterior stroma through Descemet membrane endothelial transfer (DMET) (ie, a "free-floating" donor Descemet graft in the recipient anterior chamber after descemetorhexis), in managing corneal endothelial disorders.

DESIGN

Nonrandomized prospective study at a tertiary referral center.

METHODS

Twelve eyes enrolled in our study, 7 suffering from Fuchs endothelial dystrophy and 5 with bullous keratopathy. The clinical outcome was monitored by biomicroscopy, optical coherence tomography, confocal microscopy, endothelial cell density, and pachymetry measurements.

RESULTS

All eyes operated on for Fuchs endothelial dystrophy showed corneal clearance, with pachymetry values returning to normal (533 ±47 μm). The denuded recipient stroma re-endothelialized with an average endothelial cell density of 797 (± 743) cells/mm(2) at 6 months after surgery. In contrast, none of the bullous keratopathy eyes showed any improvement throughout the follow-up period.

CONCLUSION

DMET may be effective in the management of Fuchs endothelial dystrophy (primarily a Descemet membrane disorder), but not in bullous keratopathy (primarily an endothelial depletion). Apparently, the indication for surgery (ie, a "dystrophy" vs a "depletion" of recipient endothelial cells) relates to the capacity of the cornea to clear. This suggests that the remaining rim of recipient endothelium (after descemetorhexis) is involved in the re-endothelialization of the recipient posterior stroma after DMET.

Transient peripheral edema following displaced corneal graft after descemet stripping automated endothelial keratoplasty (DSAEK): case presentation

Background

Descemet's Stripping with Automated Endothelial Keratoplasty (DSAEK) is constantly gaining popularity in the management of endothelial dysfunctions such as bullous keratopathy or Fuchs' dystrophy.

Case Presentation

A 36 year - old man with Fuchs' dystrophy underwent combined phacoemulsification and DSAEK of the right eye. Immediately postoperatively, corneal graft displacement and peripheral corneal edema which remained stable during the first postoperative month were evident on slit lamp examination. Three months after the procedure the peripheral edema had completely resolved and the patients' subjective symptoms were improved.

Conclusions

The purpose of this case presentation is to demonstrate that corneal graft displacement after DSAEK can lead to peripheral corneal edema that can resolve without further intervention such as graft repositioning or replacement.