Clinical outcomes of Descemet membrane endothelial keratoplasty performed in eyes with keratoconus and corneal endothelial dysfunction.

PURPOSE: To evaluate the clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) performed in eyes with comorbid keratoconus (KCN) and corneal endothelial dysfunction. METHODS: Twenty-five consecutive eyes of 14 patients with comorbid stable KCN underwent DMEK for corneal endothelial dysfunction; best spectacle corrected visual acuity (BSCVA), maximum corneal curvature (Kmax), maximum corneal power (Pmax), central corneal thickness (CCT), and intra- and postoperative complications were assessed. RESULTS: Excluding eyes requiring re-transplantation for primary graft failure (n = 3), all eyes showed improvement in BSCVA, reaching ≥ 20/40 (0.5) in 86%, ≥ 20/25 (0.8) in 55%, and ≥ 20/20 (1.0) in 27% by one month postoperatively; 90%, 76%, and 48% by 6 months postoperatively; and 88%, 76%, and 47% by 12 months postoperatively. CCT decreased from 571µm preoperatively to 485µm at 1 month (p < 0.001) and 481µm at 12 months (p < 0.001). Kmax decreased by a median of 1.4 diopters (D) at 1 month (p = 0.003) and 3.1 D at 12 months (p = 0.021), and every eye with a preoperative Kmax ≥ 46 D demonstrated flattening. Pmax decreased by 2.1 D at 1 month (p = 0.001) and 4.0 D at 12 months (p = 0.016). CONCLUSION: DMEK is technically feasible in eyes with comorbid KCN and may give excellent outcomes visual and refractive outcomes, including significant corneal flattening, which may potentially create a visually significant hyperopic shift in patients with severely ectatic corneas.

Five-Year Graft Survival and Clinical Outcomes of 500 Consecutive Cases After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To report the 5-year graft survival and clinical outcomes after Descemet membrane endothelial keratoplasty (DMEK). METHODS: A retrospective, interventional case series was performed at a tertiary referral center. Five hundred eyes of 393 patients that underwent DMEK for Fuchs endothelial corneal dystrophy, bullous keratopathy, failed previous corneal transplants other than DMEK, or other indications were evaluated for graft survival, best-corrected visual acuity (BCVA), endothelial cell density, postoperative complications, and retransplantation rate. RESULTS: Kaplan-Meier analysis demonstrated an estimated survival probability of 0.90 [95% confidence interval, 0.87-0.94] for the entire cohort at 5 years after DMEK. At this time point, 82% of the eyes achieved a BCVA of ≥20/25 (0.8), 54% achieved ≥20/20 (1.0), and 16% achieved ≥20/17 (1.2). BCVA continued to improve from 6 to 36 months after DMEK surgery (P ≤ 0.005) and then remained stable up to 60 months postoperatively (P > 0.08). Preoperative donor endothelial cell density averaged 2530 (±210) cells/mm and decreased by 37% at 6 months, 40% at 1 year, and 55% at 5 years after DMEK surgery (P < 0.001 between all follow-up time points). During the study period, allograft rejection episodes developed in 2.8% of the eyes, primary graft failure occurred in 0.2%, and secondary graft failure in 2.8% of the eyes. Re-keratoplasty was required in 8.8% of the eyes. CONCLUSIONS: Five-year graft survival after DMEK is high, and visual acuity outcomes remain excellent and are accompanied by a low longer-term complication rate.

Effect of Surgical Indication and Preoperative Lens Status on Descemet Membrane Endothelial Keratoplasty Outcomes.

PURPOSE: To analyze 6-month results of 1000 consecutive Descemet membrane endothelial keratoplasty (DMEK) cases, and to evaluate if outcomes are influenced by surgical indication and preoperative lens status. DESIGN: Retrospective, interventional case series. METHODS: A series of 1000 eyes (738 patients) underwent DMEK mainly for Fuchs endothelial corneal dystrophy (FECD; 85.3%) or bullous keratopathy (BK; 10.5%). Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density, postoperative complications, and retransplantations. RESULTS: At 6 months after DMEK, there was no difference in BCVA outcome between FECD and BK eyes (P = .170), or between phakic and pseudophakic FECD eyes (P = .066) after correcting for patient age and preoperative BCVA. Endothelial cell loss at 6 months postoperatively was similar for phakic and pseudophakic FECD eyes (39%; P = .852), but higher for BK eyes than for FECD eyes (46% vs 39%, P = .001). Primary and secondary graft failure occurred in 3 (0.3%) and 2 eyes (0.2%), respectively, and 7 eyes developed allograft rejection (0.7%). Eighty-two eyes (8.2%) received rebubbling for graft detachment and retransplantation was performed in 20 eyes (2.0%). Rebubbling was more often required in eyes treated for BK vs FECD eyes (12.4% vs 7.4%, P = .022). CONCLUSION: DMEK consistently provides excellent short-term results, with similar high visual acuity levels for both FECD and BK eyes. As preoperative lens status did not influence DMEK outcomes, for phakic FECD eyes with a still relatively clear crystalline lens, lens preservation may be preferable in a selected group of younger patients, who may still benefit from their residual accommodative capacity.

Quarter-Descemet Membrane Endothelial Keratoplasty: One- to Two-Year Clinical Outcomes.

PURPOSE: To report clinical outcomes of the first Quarter-Descemet membrane endothelial keratoplasty (Quarter-DMEK) case series performed for central Fuchs endothelial corneal dystrophy. METHODS: This is a prospective, interventional case series analyzing the clinical outcomes of 19 eyes of 19 patients with central Fuchs endothelial corneal dystrophy, that is, with guttae predominantly in the 6- to 7-mm optical zone, who underwent unilateral Quarter-DMEK at a tertiary referral center. Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (ECD), and postoperative complications. Included eyes had up to 2 years of postoperative follow-up. RESULTS: At 6 months postoperatively, all eyes reached a BCVA of ≥20/40 (≥0.5): 18 of 19 eyes (95%) with ≥20/25 (≥0.8) and 9 of 19 eyes (42%) with ≥20/20 (≥1.0). Thereafter, BCVA remained stable up to 2 years postoperatively. The mean donor ECD decreased from 2842 ± 139 cells/mm (n = 19) before implantation to 913 ± 434 cells/mm (-68%) at 6 months (n = 19), 869 ± 313 cells/mm (-70%) at 12 months (n = 18), and 758 ± 225 cells/mm (-74%) at 24 months (n = 13) after Quarter-DMEK. Visually significant graft detachment requiring rebubbling occurred in 8 of 19 eyes (42%). CONCLUSIONS: Quarter-DMEK surgery yields visual outcomes similar to those of conventional DMEK and may potentially quadruple the availability of endothelial grafts. Further modifications of the graft preparation and the surgical technique may improve clinical outcomes in terms of lower ECD decrease and fewer graft detachments.

Are Descemet Membrane Ruptures the Root Cause of Corneal Hydrops in Keratoconic Eyes?

PURPOSE: To challenge the current consensus on the mechanism causing corneal hydrops in eyes with keratoconus (KC). DESIGN: Retrospective, interventional case series. METHODS: Sixteen eyes of 10 patients with comorbid KC and Fuchs endothelial corneal dystrophy (FECD) underwent uncomplicated Descemet membrane endothelial keratoplasty (DMEK), and 5 eyes of 5 patients with KC alone underwent Bowman layer (BL) transplantation complicated by inadvertent perforation of the posterior corneal stroma and Descemet membrane (DM). The presence or absence of hydrops was assessed by intra- and postoperative optical coherence tomography and by slit-lamp biomicroscopy. RESULTS: None of the 16 DMEK eyes manifested a hydrops at any time during or after surgery. By contrast, all 5 eyes undergoing BL transplantation complicated by posterior corneal perforation demonstrated a corneal hydrops, evident both intra- and postoperatively. CONCLUSIONS: In eyes with KC, even the complete removal of DM did not produce a hydrops, whereas a combined defect in DM and the posterior corneal stroma seemed to consistently elicit a typical corneal hydrops.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty in Eyes With a Glaucoma Drainage Device.

PURPOSE: To evaluate the feasibility and clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in eyes with a glaucoma drainage device (GDD). DESIGN: Retrospective, interventional case series. METHODS: Clinical outcomes of 23 DMEK procedures for bullous keratopathy (52%), failed previous transplant (39%), or Fuchs endothelial corneal dystrophy (9%) in 20 eyes (19 patients) with a GDD were retrospectively analyzed at 2 tertiary referral centers. Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (ECD), postoperative complications, and graft survival. RESULTS: Mean length of postoperative follow-up after DMEK was 19 (±17) months. Kaplan-Meier survival analysis showed an 89% cumulative graft success rate at 1 year postoperatively. At 1 year postoperatively (n = 15 eyes), BCVA improved by ≥2 Snellen lines in 11 eyes (73%) and remained stable in 4 eyes (27%). Donor ECD decreased by 37% (n = 14), 60% (n = 11), and 71% (n = 11) at 1, 6, and 12 months postoperatively, respectively. Postoperative complications up to 2 years postoperatively comprised pupillary block in 1 eye (successfully reversed by partial air removal), visually significant graft detachment requiring rebubbling in 5 eyes (22%), allograft rejection successfully reversed with topical steroids in 2 eyes (9%), secondary graft failure in 2 eyes (9%), and cataract in 1 of 3 phakic eyes (33%). Re-keratoplasty was required in 2 eyes (9%). CONCLUSIONS: With specific surgical modifications, DMEK provided acceptable clinical outcomes when taking the complexity of these eyes into account. However, presence of a GDD may reduce graft survival times and may pose a risk for more frequent regrafting.

Manual mid-stromal dissection as a low risk procedure to stabilize mild to moderate progressive keratoconus.

BACKGROUND: To evaluate the efficacy of manual mid-stromal dissection in stabilizing progressive keratoconus. METHODS: Surgeries were performed in 16 eyes of 14 patients with progressive keratoconus. All eyes were examined before and at 1 day, 1 week, 1, 3, 6 and 12 months after surgery, and every 6 months thereafter. Pentacam (simK, Kmax and pachymetry), best corrected visual acuity (BCVA) and subjective refraction were recorded up to the latest follow-up visit (mean follow-up time 6.6 ± 2.4 years). RESULTS: All surgeries were uneventful, and no postoperative complications occurred. Keratometry values (n = 15) stabilized in 6/11 eyes (55%) with a preoperative Kmax < 60.0 diopter (D), while all eyes > 60 D showed continued progression. In 11/15 eyes (73%) pachymetry was unchanged. BCVA with spectacles remained stable in 7/12 eyes (58%) and improved ≥2 Snellen lines in 5/12 eyes (42%). BCVA with a contact lens remained stable in 4/9 eyes (44%), improved ≥2 Snellen lines in 3/9 eyes (33%) and deteriorated in 2/9 eyes (22%). CONCLUSIONS: Manual mid-stromal dissection was effective in 50% of keratoconic corneas with Kmax values < 60 D and may be considered in cases ineligible for other interventions such as UV-crosslinking, stromal ring implantation or Bowman layer transplantation. An advantage of the procedure may be that the tissue is unaltered and that no synthetic or biological implant is required.

Bowman layer transplantation in the treatment of keratoconus.

Several treatment options corresponding to the grade of keratoconus have been established. These are ultra-violet corneal crosslinking and intracorneal ring segments for mild to moderate keratoconus, and penetrating keratoplasty or deep anterior lamellar keratoplasty for the more advanced cases of keratoconus. Bowman layer transplantation was developed as a procedure for patients with advanced, progressive keratoconus. The technique consists of transplanting an isolated donor Bowman layer into a mid-stromal pocket of a keratoconic cornea resulting in corneal flattening and stabilization against further ectasia. Thus, it aims at corneal stabilization in eyes with advanced keratoconus, and enabling continued contact lens wear for normal visual functionality. By being a sutureless procedure and using an acellular graft, it potentially avoids commonly known suture and graft-related complications of penetrating or deep anterior lamellar keratoplasty. The treatment seems to be a promising option in the management of advanced keratoconus in order to postpone or prevent a more invasive corneal surgery, while minimizing the risk of complications and allowing less stringent surveillance and less intensive medical therapy.

Asymmetrical endothelial cell migration from in vitro Quarter-Descemet membrane endothelial keratoplasty grafts.

PURPOSE: To investigate in vitro central and peripheral corneal endothelial cell (EC) migration from Quarter-Descemet membrane endothelial keratoplasty (Quarter-DMEK) grafts. METHODS: Quarter-DMEK grafts were obtained from 10 corneas ineligible for transplantation but with intact and viable ECs. Ten Quarter-DMEK grafts were 'sandwiched' between two glass slides and cultured over 1 week in a humidified atmosphere at 37 °C and 5% CO2 . Cell migration was evaluated by light microscopy at standardized time intervals. In addition, immunohistochemistry analyses were performed to assess the detailed structural organization of ECs in the corneal centre and far periphery. RESULTS: Endothelial cell (EC) migration occurred from the radial cut graft edges, but not from the far peripheral area. Cell migration followed three different migration patterns: (1) individual cell migration, (2) uncoordinated cell migration of cell clusters and (3) collective migration in which ECs moved as a sheet. Immunostaining showed the presence of ECs up to the far periphery but with different expression patterns of phenotypical markers ZO-1, Na+ /K+ -ATPase and vimentin compared to central ECs. CONCLUSION: In vitro EC migration from Quarter-DMEK grafts occurs along the radial cut edges with a decrease in migration activity towards the corneal far periphery. No migration occurred along the outer peripheral corneal edge possibly due to a different anatomical matrix in the far periphery. Hence, ECs from the far periphery may not contribute to corneal clearance of the adjacent bare area after Quarter-DMEK surgery, but these cells may constitute a valuable cellular reserve on the graft.

Outcomes of Hemi-Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Corneal Dystrophy.

PURPOSE: To report the mid-term outcomes of hemi-Descemet membrane endothelial keratoplasty (hemi-DMEK) performed for Fuchs endothelial corneal dystrophy (FECD). METHODS: In this prospective, interventional case series, we evaluated clinical outcomes of 10 eyes from 10 patients who underwent hemi-DMEK for FECD. Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (ECD), central pachymetry, and postoperative complications. RESULTS: At 1 year postoperatively, 7/7 eyes (excluding 2 eyes with low visual potential) reached a BCVA of ≥20/40 (≥0.5), 6/7 (86%) ≥20/25 (≥0.8), 4/7 (57%) ≥20/20 (≥1.0), and 2/7 (29%) 20/17 (≥1.2). BCVA remained stable until 2 years postoperatively (P ≥ 0.05) and further improved thereafter (P < 0.05). Mean ECD decreased from 2740 (±180) cells/mm preoperatively to 850 (±300) cells/mm (n = 9) at 1 year (P ≤ 0.05) and showed an annual decrease of on average 6% to 7% thereafter (P ≥ 0.05 between consecutive follow-ups). Pachymetry decreased from preoperatively 745 (±153) µm to 533 (±63) µm (n = 9) and 527 (±35) µm (n = 8) at 1 and 3 years postoperatively, respectively. Within the first 6 postoperative months, 4/10 eyes underwent rebubbling for visually significant graft detachment. One eye received secondary circular DMEK for persistent graft detachment 1 month postoperatively; another eye developed secondary graft failure 2.5 years postoperatively, and 1 eye was suspected for an allograft reaction 1.5 years postoperatively. CONCLUSIONS: Hemi-DMEK may render visual outcomes comparable to those achieved by conventional DMEK. Despite low ECD counts by 6 months, ECD levels remain fairly stable thereafter. Hence, hemi-DMEK may become a potential alternative technique for treatment of FECD while increasing the yield of the endothelial tissue pool.

Descemet Membrane Endothelial Transfer: Ultimate Outcome.

PURPOSE: To evaluate the clinical outcome of 16 eyes undergoing Descemet membrane endothelial transfer (DMET). METHODS: In this retrospective cohort study, a consecutive series of 16 eyes from 16 patients was evaluated after subtotal detachment of the Descemet graft after a Descemet membrane endothelial keratoplasty procedure (n = 8) or intended DMET (n = 8) for either Fuchs endothelial dystrophy (n = 10) or bullous keratopathy (BK; n = 6). RESULTS: All 8 Descemet membrane endothelial keratoplasty procedures were complicated by subtotal detachment of the donor graft. The remaining 8 eyes that underwent a DMET procedure were uneventful and no postoperative complications occurred, except 1 eye with BK that experienced a postoperative wound leak. Throughout all postoperative time points, the partially attached status of all Descemet grafts was maintained. Although all eyes operated on for Fuchs endothelial dystrophy showed initial central corneal clearance, no eye operated for BK demonstrated any degree of corneal deturgescence. Ultimately, all 16 corneas decompensated and 15 of the 16 patients elected retransplantation, while 1 patient declined further surgery for health reasons. Retransplantation was performed on average 10.3 (±7.4) months (range, 3-31 mo) postoperatively. CONCLUSIONS: Ultimately, regardless of the etiology of endothelial dysfunction, DMET fails to provide satisfactory results in the long term; durable corneal clearance may therefore require the presence of a nearly completely attached Descemet graft.

Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty: An Updated Review.

PURPOSE: To provide an overview of the current literature on donor tissue preparation for Descemet membrane endothelial keratoplasty (DMEK). METHODS: A comprehensive database search without date restrictions was performed in PubMed and in The Cochrane Library in May, 2017. Keywords included Descemet membrane endothelial keratoplasty, corneal transplantation, graft, harvest, dissection, preparation, endothelial cell, and endothelial cell density. Articles aiming to describe or evaluate a technique for DMEK graft preparation were considered eligible and were included in this review. RESULTS: A graft dissection technique that provides consistent tissue qualities and a low risk of preparation failure is essential for surgeons and eye banks preparing DMEK tissue. Various techniques have been described aiming to facilitate DMEK graft dissection, including manual dissection, pneumatic dissection, and hydrodissection. All show a trend toward a no-touch technique, for example, without direct physical tissue manipulation during tissue harvesting, as a potential ideal approach to minimize graft damage. CONCLUSIONS: An overview of the current harvesting techniques available for DMEK may benefit corneal surgeons and eye banks in choosing the best approach for each specific user.

Minimizing Graft Preparation Failure in Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To report the failure rate of 2 graft preparation techniques for Descemet membrane endothelial keratoplasty (DMEK) and to evaluate how to minimize graft preparation failure. METHODS: Retrospective, nonrandomized study at an eye bank specialized in graft preparation for lamellar keratoplasty. For 1416 donor corneas, the DMEK graft preparation failure rate was evaluated for 2 different techniques, technique I: "Standardized traditional technique" (n = 341) and technique II: "Standardized no-touch technique" (n = 933), and for grafts that were converted from technique II to technique I during preparation (n = 142). RESULTS: The overall failure rate averaged 3.9% (55/1416): 7.0% (24/341) for technique I and 2.9% (31/1075) for technique II (P < 0.05). Tissue preparations which were converted from technique II to technique I failed in 13.4% (19/142), whereas for grafts that were entirely prepared by technique II, the failure rate was only 1.3% (12/933). The endothelial cell density decrease (before compared with after preparation) did not differ for both techniques (1.1% vs. 0.2%, P > 0.05). CONCLUSIONS: Various DMEK graft preparation techniques may provide failure rates of <4%. A "no-touch preparation" approach (technique II) may combine good graft quality (completely intact endothelial cell layer, ie, negligible preparation-induced endothelial cell density decrease) with low risk of dissection failure, leaving the possibility of conversion to "traditional preparation" (technique I) as a backup method.

Simple technique for graft insertion in Descemet-stripping (automated) endothelial keratoplasty using a 30-gauge needle.

We describe a needle insertion technique for graft insertion in Descemet-stripping (automated) endothelial keratoplasty (DSEK/DSAEK). A folded donor posterior corneal disk is inserted through a 5.0 mm scleral tunnel incision over a plastic glide using a 30-gauge needle. The technique enables safe and easy graft insertion without vertical or horizontal compression of the donor tissue, causing minimal trauma to the donor endothelium and/or host structures.