Air Versus Sulfur Hexafluoride Gas Tamponade in Descemet Membrane Endothelial Keratoplasty: A Fellow Eye Comparison

Bubble-graft coverage after Descemet Membrane Endothelial Keratoplasty depending on gaze angle

PURPOSE

In Descemet Membrane Endothelial Keratoplasty (DMEK) a gas bubble is usually used to attach the graft to the host cornea. In this study, we observed the bubble size and bubble-graft coverage at different gaze angles following DMEK.

METHODS

This observational prospective study analyzed 465 images of patients who underwent an uneventful DMEK. Intraoperatively, the anterior chamber was filled up to 90% of its volume with a 20% Sulfur Hexafluoride (SF6) gas-air mixture. Postoperatively, the bubble was photographed daily in different gaze angles ranging from a supine position (0°) to an upright position (90°) and a slightly inclined position (105°). The primary outcomes were bubble-graft coverage and bubble diameters depending on the gaze angle and time after DMEK.

RESULTS

The highest bubble-graft coverage was achieved at a 0° gaze angle at all times of measurement. In the first 48 h after DMEK, the mean bubble-graft coverage was over 85% at a gaze angle between 0° and 45°. Starting 72 h after DMEK, the graft coverage declined at all gaze angles. The graft coverage at a 0° gaze angle was 88.61 ± 10.90% after 96 postoperative hours, while the graft coverage was below 85% at all other gaze angles.

CONCLUSION

Our clinical results provide novel insight into variation in bubble-graft coverage as a function of gaze angle and may be used to aid in patient counselling for appropriate body positioning following DMEK to prevent early graft detachment. Maintaining supine positioning seems to be most advantageous starting 48 h after DMEK.

Retrospective Study of Preoperative Laser Peripheral Iridotomy Versus Intraoperative Surgical Peripheral Iridectomy in Descemet Membrane Endothelial Keratoplasty

PURPOSE

The aim of this study was to examine the outcomes of laser peripheral iridotomy (LPI) and surgical peripheral iridectomy (SPI) for Descemet membrane endothelial keratoplasty (DMEK) and DMEK with cataract extraction (triple DMEK).

METHODS

This retrospective interventional study included 135 eyes of 135 patients who underwent DMEK alone or triple DMEK. Primary outcomes were graft detachments necessitating rebubbling, repeat grafts, and pupillary block. The secondary outcomes included rejection, cystoid macular edema, uveitis, intraoperative hyphema, visual disturbances, and surgical time.

RESULTS

Thirty-one eyes in the LPI group and 104 eyes in the SPI group were included. Fifty-six eyes had DMEK alone, and 79 had triple DMEK. Visually significant graft detachments occurred in 7 of 31 eyes in the LPI group versus 19 of 104 eyes in the SPI group ( P = 0.61). No statistical significance in DMEK alone versus triple DMEK groups ( P = 0.61 vs. P > 0.99). Two patients in the LPI group and 5 in the SPI group required regraft ( P = 0.66). One (3.2%) experienced pupillary block compared with 5 (4.8%) ( P = 0.99) in the LPI and SPI groups, respectively. Secondary outcomes were similar in both groups ranging from 0% to 3% ( P > 0.99). None had visual disturbances. In DMEK alone, duration of surgery was significantly shorter in the LPI versus SPI group (32.8 vs. 44.1 minutes, P = 0.02).

CONCLUSIONS

This study demonstrated similar outcomes between LPI and SPI, although the LPI group had a shorter duration of surgery when DMEK was performed alone. The remainder of the outcomes demonstrated no statistically significant differences.

Comparison of efficacy of three gases for anterior chamber tamponade in Descemet's membrane endothelial keratoplasty

PURPOSE

To compare the efficacy of three different gases for intraocular tamponade: 100% air, 10% perfluoropropane (C3F8), and 10% sulfur hexafluoride (SF6), in Descemet's membrane endothelial keratoplasty (DMEK).

MATERIALS AND METHODS

The medical records of 138 patients who underwent DMEK were reviewed retrospectively, with the primary outcome being the rebubbling rate in the first week following surgery. Other clinical outcomes, such as best-corrected visual acuity (BCVA), central corneal thickness (CCT), incidence of rebubbling after the first week, endothelial cell density (ECD), graft detachment, graft failure, pupillary block, and intraocular pressure (IOP) changes were also analyzed.

RESULTS

Of the 138 patients, 57 were in group 1 (treated with air), 44 in group 2 (treated with 10% C3F8), and 37 in group 3 (treated with 10% SF6). Group 3 showed significantly lower rates of graft detachment and rebubbling compared to groups 1 and 2 (P<0.001). However, there was no significant difference in postoperative BCVA among the groups. At one year, the mean endothelial cell loss was 32% in group 1, 30% in group 2, and 33% in group 3 (P=0.715). One patient in group 1 experienced pupillary block and increased IOP, while there were no such occurrences in the other groups. There was no difference between the groups in terms of graft failure.

CONCLUSION

The use of 10% SF6 in DMEK surgery may be a good option due to its efficacy in preventing graft detachment, low rebubbling rate, and potential for minimizing complications.

Comparison of 20% SF6 and 6% C3F8 Gas for Anterior Chamber Tamponade in Endothelial Keratoplasty

PURPOSE

The aim of this study was to compare the rates of rebubbling after Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping endothelial keratoplasty (DSEK) between patients who had anterior chamber (AC) graft tamponade with 20% sulfur hexafluoride gas (SF6) and 6% perfluoropropane gas (C3F8).

METHODS

The charts of 431 patients undergoing EK from June 8, 2010, to April 16, 2023, were reviewed. Patients undergoing EK alone as well as combined procedures with cataract extraction and intraocular lens implantation were included. Eyes with tube shunts, anterior chamber intraocular lenses, and large peripheral iridotomy with posterior loss of bubble, and patients undergoing cyclophotocoagulation or synechialysis were excluded. All rebubble procedures were performed within 1 month after initial surgery.

RESULTS

A total of 346 eyes using SF6 and 167 eyes using C3F8 were analyzed. Overall, 46 eyes (9%) required rebubbling; 33 eyes (10%) in the SF6 group and 13 eyes (8%) in the C3F8 group. For those patients undergoing DMEK, the odds of requiring rebubbling in the C3F8 group were about 22% lower than that of patients in the SF6 group (operating room [OR]: 0.782; P < 0.001). For patients undergoing DSEK, however, the gas type did not significantly affect rebubbling rates (P = 0.99).

CONCLUSIONS

For DMEK, utilization of 6% C3F8 as an AC tamponade was associated with a significantly lower odds of graft rebubbling compared with 20% SF6. Gas type did not result in a significant difference for DSEK. Utilization of 6% C3F8 for graft tamponade could be considered to reduce graft detachment rates in DMEK.

Evaluating the forces involved in bubble management in DMEK surgery: mathematical and computational model with clinical implications

PURPOSE

To model postoperative forces involved in Descemet membrane endothelial keratoplasty (DMEK) tissue adherence and bubble management, including the impact of surface tension on graft support, with a view towards clinical applications.

SETTING

Tennent Institute of Ophthalmology, Glasgow, and James Watt School of Engineering, University of Glasgow, Glasgow, United Kingdom.

DESIGN

Mathematical modelling and computer simulation.

METHODS

Theoretical modelling of biphasic flow and interaction of gas, liquid and tissue within the anterior chamber for static horizontal scenario A (adherent DMEK with mobile bubble) and dynamic vertical scenario B (release of bubble due to pupil block following DMEK).

RESULTS

The model assumed incompressibility for both fluids within realistically achievable pressure ranges. Cahn-Hilliard Navier-Stokes equations were discretised through the application of the Finite Element Method. Mathematical modelling and computer simulation showed bubble size, corneal curvature and force intensity influences surface tension support for DMEK tissue in scenario A. Scenario B demonstrated complex, uneven distribution of surface pressure on the DMEK graft during uncontrolled bubble release. Uneven pressure concentration can cause local tissue warping, with air/fluid displacement via capillary waves generated on the fluid-air interface adversely impacting DMEK support.

CONCLUSIONS

We have quantitatively and qualitatively modelled the forces involved in DMEK adherence in normal circumstances. We have shown releasing air/gas can abruptly reduce DMEK tissue support via generation of large pressure gradients at the liquid/bubble/graft interfaces, creating negative local forces. Surgeons should consider these principles to reduce DMEK graft dislocation rates via optimised bubble size to graft size, longer acting bubble support and avoiding rapid decompression where possible.

Ultrathin Descemet Stripping Automated Endothelial Keratoplasty (UT-DSAEK) versus Descemet Membrane Endothelial Keratoplasty (DMEK)-a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Endothelial keratoplasty (EK) is a commonly performed transplant procedure used in the treatment of corneal endothelial dysfunction. The aim of this systematic review and meta-analysis is to evaluate the differences in visual acuity outcomes, endothelial cell density (ECD) and complications between two forms of EK, ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) and Descemet membrane endothelial keratoplasty (DMEK).

METHODS

A literature search of MEDLINE, Embase and Cochrane Library was conducted to identify studies reporting comparative results of UT-DSAEK versus DMEK. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used for search strategy. Of 141 titles, 7 studies met the inclusion criteria; best corrected visual acuity (BCVA) (LogMAR), ECD (cells/mm2), and complications were compared, with all statistical analysis performed using Review Manager.

RESULTS

A total of 362 eyes were included for analysis. DMEK resulted in significantly better BCVA at 3 months (0.14 vs 0.22, p = 0.003), 6 months (0.08 vs 0.18, p = 0.005) and 1 year post-op (0.07 vs 0.14, p = 0.0005). UT-DSAEK resulted in significantly lower total complications (25.2% vs 57.3%, p = 0.0001) and rates of re-bubbling (11.0% vs 33.7%, p = 0.004). No differences were found in ECD between the two procedures (1541 vs 1605, p = 0.77).

CONCLUSIONS

DMEK results in superior visual acuity rates with quicker recovery. However, UT-DSAEK has a more favourable complication profile, particularly regarding lower rates of re-bubbling. Both are valuable options in the treatment of corneal endothelial disease and choice of procedure may depend on surgical expertise.

Clinical Outcomes of Descemet's Membrane Endothelial Keratoplasty without Routine Prophylactic Peripheral Iridotomy

Objectives: To analyze the outcomes and complications of Descemet's membrane endothelial keratoplasty (DMEK) performed without prophylactic peripheral iridotomy (PI). Methods: Design: Retrospective study.

SETTING

Institutional, tertiary care eye hospital.

STUDY POPULATION

All patients who underwent DMEK or DMEK combined with phacoemulsification (DMEK triple) for Fuchs endothelial dystrophy, using a standardized protocol between August 2016 and July 2021, were included. Previous glaucoma surgery, laser PI, aphakia, or complicated pseudophakia were excluded.

MAIN OUTCOME MEASURES

Primary outcomes: Incidence of pupillary block (PB).

SECONDARY OUTCOMES

Graft detachment (GD), rebubbling rates, uncorrected (UCDVA) and best corrected logMAR distance visual acuity (BCDVA), and endothelial cell loss (ECL) at six months. Data were analyzed using the chi-square test and stepwise backward regression analysis. Results: 104 eyes of 72 patients were included. Four eyes (3.8%) developed PB; in two of these cases, standard protocol was not followed. Overall minor GD occurred in 43.2% (n = 45); significant GD was present only in 7 eyes (6.6%). Overall slit lamp rebubbling rate was 30% (n = 35), though only four patients were rebubbled in theatre (3.8%). PB, GD, and rebubbling rates did not vary with the surgeon, surgery, or tamponade (air or SF6 gas). UCDVA, BCDVA, and ECL at 6 months were 0.29 ± 0.31, 0.20 ± 0.28, and 40.46 ± 20.36%, respectively. Conclusions: Compared to previously reported outcomes of DMEK with PI, our results of PI less DMEK using a standardized protocol have a similar incidence of pupillary block, graft detachment, and rebubbling, with comparable visual acuity and endothelial cell loss.

Influence of Body Position on Intraocular Pressure After Descemet Membrane Endothelial Keratoplasty: A Prospective Randomized Trial

PURPOSE

The purpose of this study was to analyze the influence of patient positioning on intraocular pressure (IOP) after Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic patients treated for Fuchs endothelial corneal dystrophy.

METHODS

Forty patients were included in this prospective, single-blinded, randomized controlled clinical trial. Patients received a YAG iridotomy 1 day before surgery and an 80% anterior chamber tamponade [20% concentration of sulfur hexafluoride (SF6)]. Postoperative positioning was either supine (group 1) or seated (group 2, at least 30 degrees upper-body high position). IOP was measured with iCare.

RESULTS

There was no statistically significant difference in IOP postoperatively [group 1 vs. group 2-after 1h: 13.9 mm Hg (±4.2 mm Hg) versus 13.6 mm Hg (±4.1 mm Hg) ( P = 1.00); after 2h: 13.9 mm Hg (±5.4 mm Hg) versus 15.3 mm Hg (±4.6 mm Hg) ( P = 0.370); after 4h: 13.8 mm Hg (±4.2 mm Hg) versus 15.2 mm Hg (±4.2 mm Hg) ( P = 0.401]. In group 1, 10% of patients showed IOP decompensations well above 30 mm Hg, and in group 2, there were no IOP decompensations. Seated position led to relative risk reduction of 100% and absolute risk reduction of 10% regarding IOP decompensations. The number of patients needed to position seated to prevent 1 additional IOP decompensation was 10. Rebubbling rates, best spectacle-corrected visual acuity, and reduction of corneal thickness were comparable between the 2 groups in the follow-up period up to 1 month.

CONCLUSIONS

After DMEK in pseudophakic eyes with 80% anterior chamber tamponade, positioning patients with at least 30 degrees elevation of the upper body up immediately after surgery until bedtime prevents IOP decompensations.

A Novel Murine Model of Endothelial Keratoplasty

PURPOSE

The purpose of this study was to establish a murine model of endothelial keratoplasty.

METHODS

Endothelial keratoplasty (EK) was performed using C57BL/6 donor and BALB/c recipient mice. The central endothelium and Descemet membrane were removed from the recipient cornea, and a 1.5-mm posterior lamellar donor graft was made adherent to the recipient cornea with a small amount of viscoelastic. Mice were followed through slitlamp microscopy postoperatively, and OCT was used to assess the cornea and anterior chamber and measure central corneal thickness. Histology and immunohistochemistry were performed to confirm graft adherence and endothelial cell morphology.

RESULTS

Successfully attached EK grafts were visualized in all transplanted animals. Histology and immunostaining confirmed proper graft orientation and adherence, as well as the presence of donor endothelium on transplanted grafts. We observed maximal corneal edema in all animals at day 1 postoperatively which gradually subsided. EK graft survival was 97% at 8 weeks.

CONCLUSIONS

In this study, we describe a novel murine model for EK which we anticipate will enable detailed investigation into the cellular and molecular mechanisms involved in EK pathobiology.

Specifying Risk of Intraocular Lens Opacification After Endothelial Keratoplasty for Different Intraocular Lens Models: A Retrospective Monocentric Cohort Study

PURPOSE

The aims of this study were to calculate the specific risk of opacification for different intraocular lens (IOL) models and to determine whether differences exist, even between lenses made of similar acrylic materials.

METHODS

This is a retrospective cohort study of all patients who underwent endothelial keratoplasty (EK), either after or in conjunction with cataract surgery, from June 2009 to October 2020 at Fundación Jiménez Díaz Hospital.

RESULTS

Three hundred seventy-two eyes of 308 patients with a median follow-up of 856 days [interquartile range (IQR): 384-1570] were included, of which 128 IOLs were hydrophobic, 120 hydrophilic, and 124 unknown. 12.9% of IOLs opacified after a median of 466 days (IQR: 255-743). Visual acuity (VA) was significantly lower in the opacified IOL group [0.51 (IQR: 0.36-1.13)] compared with the nonopacified group [0.22 (IQR: 0.11-0.65)] ( P < 0.001). IOL explantation and exchange was performed in 10 eyes, in which VA improved markedly, from 1.75 (IQR: 0.99-3.00) to 0.60 (IQR: 0.36-0.86) ( P = 0.004). IOL material and opacification events were not independent ( P < 0.001). Significant differences were found between the Akreos ADAPT AO and MI60P models and the Asphina 409M model ( P = 0.022). No significant differences were found in the opacification ratio for hydrophilic IOLs in the clinical diagnosis ( P = 0.11), the type of EK ( P = 0.25), the rebubbling rate ( P = 0.44), or the tamponade used ( P = 0.36).

CONCLUSIONS

Hydrophilic lenses should be avoided in patients at risk of requiring EK. It is important to know the probability of opacification of each IOL model to balance risk and benefits when planning an EK procedure because not all lenses opacify equally. Opacification is an unwanted event with a negative impact on VA, making IOL explantation and exchange the only viable treatment, although one that is not without risks.

Descemetorhexis Without Endothelial Keratoplasty in Fuchs Endothelial Corneal Dystrophy: A Systematic Review and Meta-Analysis

PURPOSE

Descemetorhexis without endothelial keratoplasty (DWEK) is an innovative corneal intervention and potentially effective against Fuchs endothelial corneal dystrophy (FECD). We aimed to conduct a systematic review and meta-analysis on the outcomes of DWEK, associated or not with phacoemulsification (PKE) and rho-kinase inhibitor (RHOKI) in FECD.

METHOD

PubMed, Cochrane Library, Embase, ClinicalTrials.gov , and Science Direct were searched for studies until November 29, 2020. We performed random-effects meta-analyses and meta-regressions, stratified by the type of intervention and descemetorhexis size (PROSPERO CRD42020167566).

RESULTS

We included 11 articles (mainly case series, both prospective and retrospective), representing 127 eyes of 118 patients. DWEK globally improved visual acuity (effect size = -1.11, 95% confidence interval, -1.70 to -0.52, P < 0.001) and pachymetry (-1.25, -1.92 to -0.57, P < 0.001), without significant effects on endothelial cell count (-0.59, -2.00 to 0.83, P = 0.419). The 3 types of interventions (ie, DWEK ± RHOKI, DWEK ± PKE, and DWEK ± PKE ± RHOKI) improved visual acuity and pachymetry in FECD. A descemetorhexis size ≤4 mm improved visual acuity (-0.72, -1.29 to -0.14, P < 0.001) and pachymetry (-0.68, -0.98 to -0.38, P < 0.001), whereas >4 mm did not. Overall, DWEK failure (ie, the prevalence of EK after DWEK) was 17% (7%-27%, P < 0.001), with 4% (0%-8%, P = 0.08) for a descemetorhexis size ≤4 mm.

CONCLUSIONS

Despite the lack of comparative studies, DWEK seemed to improve visual acuity and pachymetry in early stages of FECD. A descemetorhexis size ≤4 mm was associated with the best visual outcomes and pachymetry.

“Endothelium-Out” and “Endothelium-In” Descemet Membrane Endothelial Keratoplasty (DMEK) Graft Insertion Techniques: A Systematic Review With Meta-Analysis

Background

We evaluated the visual outcomes and complications of “endothelium-out” and “endothelium-in” Descemet membrane endothelial keratoplasty (DMEK) graft insertion techniques.

Materials and Methods

Electronic searches were conducted in CENTRAL, Cochrane databases, PubMed, EMBASE, ClinicalTrials.gov. Study designs included clinical trials, comparative observational studies, and large case series (≥25 eyes). PRISMA guidelines were used for abstracting data and synthesis. Random-effects models were employed for meta-analyses.

Results

21,323 eyes (95 studies) were included. Eighty-six studies reported on “endothelium-out” techniques; eight studies reported on “endothelium-in” techniques. One study compared “endothelium-out” to “endothelium-in” techniques. Eighteen “endothelium-out” studies reported that 42.5–85% of eyes achieved best-corrected visual acuity (BCVA) ≥20/25 at 6 months; pooled proportion of eyes achieving BCVA ≥20/25 at 6 months was 58.7% (95% CI 49.4–67.7%,15 studies). Three “endothelium-in” studies reported that 44.7–87.5% of eyes achieved BCVA of ≥20/25 at 6 months; pooled proportion of eyes achieving BCVA ≥20/25 at 6 months was 62.4% (95% CI 33.9–86.9%). Pooled mean endothelial cell loss was lower in the “endothelium-in” studies (28.1 ± 1.3%, 7 studies) compared to “endothelium-out” studies (36.3 ± 6.9%,10 studies) at 6 months (p = 0.018). Graft re-bubbling rates were higher in the “endothelium-out” studies (26.2%, 95% CI 21.9–30.9%, 74 studies) compared to “endothelium-in” studies (16.5%, 95% CI 8.5–26.4%, 6 studies), although statistical significance was not reached (p = 0.440). Primary graft failure rates were comparable between the two groups (p = 0.552). Quality of evidence was considered low and significant heterogeneity existed amongst the studies.

Conclusion

Reported rates of endothelial cell loss were lower in “endothelium-in” DMEK studies at 6 months compared to “endothelium-out” studies. Outcomes of “endothelium-in” techniques were otherwise comparable to those reported in “endothelium-out” studies. Given the technical challenges encountered in “endothelium-out” procedures, surgeons may consider “endothelium-in” techniques designed for easier intra-operative DMEK graft unfolding. “Endothelium-in” studies evaluating outcomes at longer time points are required before conclusive comparisons between the two techniques can be drawn.

Descemet membrane endothelial keratoplasty: analysis of clinical outcomes of patients with 8-10 years follow-up

PURPOSE

This study aimed to evaluate the clinical outcomes up to 10 years after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

In this retrospective, consecutive, single-center case series the medical files of eyes which have received DMEK between 2009 and 2012 for the treatment of endothelial dysfunction was evaluated regarding follow-up time and clinical outcomes. Annual examinations of best-corrected visual acuity (BCVA), endothelial cell density (ECD), central corneal thickness (CCT) of 66 eyes which fulfilled the criterion of a minimum of 8 years follow-up were analyzed.

RESULTS

BCVA improved from 0.55 ± 0.37 logMAR (n = 54) to 0.15 ± 0.11 (n = 47) in eyes without ocular comorbidities one year after DMEK (p < 0.001), and remained stable up to 10 years after DMEK. Mean ECD decreased to 744 ± 207 cells/mm2 (n = 39) after 9 years, and to 729 ± 167 cells/mm2 (n = 21) after 10 years, respectively. CCT decreased from 650 ± 67 μm before DMEK to 525 ± 40 μm (n = 56) after 1 year, increasing slowly to 563 ± 40 µm (n = 39) after 9 years, and to 570 ± 42 µm (n = 21) after 10 years, respectively. Graft failure occurred in 4 of 66 eyes after year 8. These 4 eyes required repeat DMEK after 101-127 months.

CONCLUSION

This study shows the long-term outcomes in a small subset of DMEK grafts. Visual acuity remained stable in spite of slowly increasing corneal thickness and diminishing endothelial cell density during the 10-year period after DMEK.

Tips, Tricks, and Guides in Descemet Membrane Endothelial Keratoplasty Learning Curve

Lamellar keratoplasty is fast becoming the most popular form of corneal transplantation. The adoption of Descemet membrane endothelial keratoplasty (DMEK) in the management of Fuchs endothelial dystrophy and pseudophakic bullous keratopathy is partly responsible for this shift in the paradigm of management of corneal pathology. The learning curve of DMEK, however, has been proven to be much steeper than previous endothelial keratoplasty procedures. To ease the procedure, experts have proposed multiple innovative techniques from tissue preparation to graft unfolding to aid the more novice surgeon. Here, we collate and share tips and tricks from our collective experiences to support the learning curve and outcomes in DMEK for both the novice and more experienced corneal transplant surgeons.

Deep Anterior Lamellar Keratoplasty with Large Descemet's Membrane Perforation: Should We Stop Conversion to Penetrating Keratoplasty?

Purpose

To evaluate the outcome of eyes with large Descemet's membrane (DM) perforation during deep anterior lamellar keratoplasty (DALK).

Methods

A retrospective, interventional case series of 12 eyes with completed DALK, despite DM perforation larger than 4 mm in its widest dimension. The main outcome measures included graft clarity, endothelial cell density (ECD), corrected distance visual acuity (CDVA), and DM detachment.

Results

The mean age of patients was 26.8 ± 11.4 years. Preoperative pathology included keratoconus (n = 10), macular dystrophy (n = 1), and postmicrobial keratitis corneal scar (n = 1). The average size of DM perforation was 6.5 mm ± 1.3 mm. At the end of the follow-up period (median 15 months, range 6-53 months), the mean CDVA was 0.32 ± 0.09 logMAR and the mean ECD was 1830.8 ± 299.7 cells/mm². Nine patients (75%) developed DM detachments postoperatively and was managed by intracameral air injection once in six eyes, and twice in three eyes. Other complications included persistent localized stromal edema at the site of DM defect in one eye and Urrets Zavalia syndrome in one eye.

Conclusion

Completing DALK in eyes with large DM perforation provides good visual acuity, endothelial cell count and may be superior to penetrating keratoplasty regarding long-term graft survival if confirmed in future comparative studies.

Risk Factors for Repeat Descemet Membrane Endothelial Keratoplasty Graft Failure

PURPOSE

To evaluate repeat Descemet membrane endothelial keratoplasty (re-DMEK) success rates and to identify risk factors for re-DMEK failure.

DESIGN

Retrospective case series.

METHODS

Settings: Institutional.

PATIENTS AND INTERVENTIONS

A chart review was performed, including all eyes with primary DMEK failure that underwent re-DMEK between 2013 and 2019 at the Toronto Western Hospital and the Kensington Eye Institute (Toronto, Ontario, Canada) and had at least 6 months of follow-up.

MAIN OUTCOME MEASURE

Predicting factors for re-DMEK outcome.

RESULTS

Of 590 consecutive DMEK surgeries, 40 eyes (6.7%) were identified for having a secondary DMEK surgery after primary DMEK failure. Etiologies for primary DMEK were Fuchs endothelial corneal dystrophy (32.5%), pseudophakic bullous keratopathy (35%), previous failed graft (27.5%), and other indications (5%). Fifty-five percent of the cohort were categorized as having a complicated anterior segment including 11 eyes with previous glaucoma surgery, 7 eyes post-penetrating keratoplasty, 4 eyes post-Descemet stripping automated endothelial keratoplasty, 3 eyes peripheral anterior synechia, 3 eyes previous pars plana vitrectomy, 2 eyes aphakia, and 1 eye each with aniridia, anterior chamber intraocular lens, and iris-fixated intraocular lens. Re-DMEK failure was documented in 12 eyes (30%) of the entire cohort. The risk factor for re-DMEK failure was the presence of a complicated anterior segment (P = .01, odds ratio = 17.0 [95% confidence interval: 1.92-150.85]), with 50% re-DMEK failure rate in this subgroup.

CONCLUSION

Re-DMEK is a viable option for cases of primary DMEK failure, especially for eyes with Fuchs endothelial corneal dystrophy as the indication for primary DMEK without other ocular morbidities; however, eyes categorized with a complicated anterior segment had high re-DMEK failure rates.</ABSTRACT>.

Non stripping descemet membrane endothelial keratoplasty in difficult cases: A case series

Endothelial keratoplasty (EK) has been increasingly used instead of penetrating keratoplasty (PK) in the management of post PK graft rejection. Both DSAEK and DMEK involve the surgical removal of the diseased host endothelial cell layer and Descemet's membrane (DM) (descemetorhexis) before transplantation, a technically challenging step, especially in post-PK eyes. Understandably, interest arose when non-stripping DMEK (nDMEK) was described in 2013, and recent studies suggested encouraging results without increased early postoperative failures or complications requiring rebubbling. The purpose of our series was to further study the feasibility and safety of nDMEK and to compare the results with traditional DMEK. This is a single center case series of 3 eyes which underwent nDMEK performed by experienced surgeons (C.P, A.M). Two eyes had nDMEK as a secondary procedure following a failed/rejected PK, while the third case underwent nDMEK on a virgin eye. Undiseased donor DM and a regular host endothelium were required to be eligible for nDMEK. The average change in CCT at last follow-up was -21.2% (±13.3). All required intracameral air injection (rebubbling) within the first few days, with a mean of 2.33 rebubblings per eye, the first one occurring at 6.33±2.52 days after surgery. Non-stripping DMEK surgery appears to be a feasible option, and results are satisfactory at mid to long term. However, in our series, the immediate postoperative period was marked by an increased rebubbling rate. While foreseeable particularly in high-risk cases, surgeons considering this technique should expect a higher risk of early rejection.

[UT-DSAEK using grafts provided by a tissue bank, a one-year follow-up study of 79 grafts]

INTRODUCTION

UT-DSAEK is a recent technique developed in order to obtain grafts thinner than a conventional DSAEK (less than 100 microns). The goal of this study was to evaluate the anatomic and clinical results over a period of one year for a retrospective series of UT-DSAEK procedures at the University Hospital of Nantes, using pre-cut grafts provided by a tissue bank, and to compare results with other existing techniques: DSAEK and DMEK.

METHODS

In this retrospective, single-center study, all patients requiring an endothelial graft over a one-year period were included. The criteria studied were visual acuity, graft thickness, pachymetry and specular microscopy, recorded on the preoperative visit, D7, M1, M3, M6 and M12.

RESULTS

Seventy-nine grafts were performed on 75 patients. The mean age was 72 years. Between the 7th day and the end of the first year, the graft thickness in the visual axis decreased from 75±29 to 60±21 microns rapidly over the first three months. The pachymetry decreased from 706±95 microns preoperatively to 561±54 microns with the same kinetics. The cell density of the graft decreased from 2604±13 cell/mm² prior to the procedure to 1551±124 cell/mm² (40% loss) at one year. The preoperative visual acuity was 1.16 logMAR, rapidly improving to 0.65 logMAR at the first month and 0.40 logMAR at one year.

CONCLUSION

This study provides a fair amount of data on the progression of UT-DSAEK grafts: a decrease in graft thickness over the first three months, corresponding to an increase in visual acuity over this same period, with a good endothelial survival rate. This technique opens new avenues for the treatment of endothelial diseases, being complementary to DMEK in terms of surgical indications.

Rebubbling of detached descemet membrane endothelial grafts at the slit lamp with 50% air fill after PI-less DMEK during COVID-19 era

PURPOSE

To describe the effective use of only 50% air fill of the anterior chamber for rebubbling partially detached Descemet Membrane Endothelial Keratoplasty (DMEK) grafts at the slit lamp at a time of restricted operating theatre access during the COVID-19 pandemic.

METHODS

We present two cases of patients who underwent rebubbling of a partially detached DMEK grafts at the slit lamp following DMEK surgery without peripheral iridotomy. The rebubbling was performed with a 27-gauge needle attached to a 1ml syringe and the patients seated at the slit lamp. Air was injected into the anterior chamber until a 50% air fill was achieved. The patients were instructed to lie supine for 30 min in clinic and the remainder of the day at home.

RESULTS

We performed two rebubbling procedures at the slit lamp using the standard needle and syringe. Both cases achieved 50% air fills without any complications. At 3 days post-procedure the air bubble had resolved and the graft appeared attached centrally and at day 14 post-procedure the two patients had a clear and attached corneal graft with corrected visual acuity of 6/7.5 and 6/9, respectively.

CONCLUSION

Rebubbling of detached DMEK grafts at the slit lamp with 50% air fill in the anterior chamber is a relatively simple and effective procedure. This provides an alternative approach for managing the complication of partially detached DMEK grafts in the era of COVID-19 with limited operating theatre access and avoids the risk of complications such as pupillary block in 'PI-less' DMEK.

Impact of Re-bubbling after Descemet Membrane Endothelial Keratoplasty on Long-term Results

Purpose/Aim of the study: Graft detachment after DMEK can be treated easily with an additional air injection - re-bubbling. The aim of our study was to investigate the effect of a re-bubbling on the postoperative outcome.Materials and Methods: In this retrospective, comparative, cohort study we included eyes from patients that underwent DMEK surgery. A graft detachment was diagnosed by slit-lamp examination and OCT scan. All eyes were divided into three groups: no re-bubbling, one re-bubbling, more than one re-bubbling. We analyzed the visual acuity, endothelial cell density and rate of graft failure.Results: In 163 of 463 eyes (35.2%) a re-bubbling was performed (119 eyes 1 re-bubbling, 44 eyes more than one re-bubbling). Visual acuity improved significantly in all groups. After controlling for donor age, reason for surgery, time of cultivation of the graft and preoperative visual acuity, no difference in the visual acuity was seen at any point of follow-up. All patients showed a significant reduction in endothelial cell density 1 month after DMEK. Controlling for donor age, reason for surgery, type of surgery (DMEK-only or DMEK combined with cataract surgery) and the time of cultivation of the graft, the difference in endothelial cell density at 1 month post-surgery between no re-bubbling and one re-bubbling was 157 cells/mm² (95% CI 2-310, p = .047) and between no re-bubbling and more than one re-bubbling 504 cells/mm² (95% CI 267 - 741, p < .001). The difference in endothelial cell density remained over the course of follow-up. Twenty patients (4.3%) developed a graft failure during postoperative follow-up. Controlling for donor age, reason for surgery and the time of cultivation of the graft, we did not find any difference in the risk of graft failure between re-bubbling categories.Conclusions: Re-bubbling increased the risk for an endothelial cell loss, but did not influence the postoperative visual acuity and the rate of graft failure.

Descemet Membrane Endothelial Keratoplasty versus Ultrathin Descemet Stripping Automated Endothelial Keratoplasty: A Multicenter Randomized Controlled Clinical Trial

PURPOSE

To compare best spectacle-corrected visual acuity (BSCVA), endothelial cell density (ECD), refractive astigmatism, and complications after Descemet membrane endothelial keratoplasty (DMEK) and ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK).

DESIGN

Prospective, multicenter randomized controlled trial.

PARTICIPANTS

Fifty-four pseudophakic eyes of 54 patients with corneal endothelial dysfunction resulting from Fuchs endothelial corneal dystrophy were enrolled in 6 corneal centers in The Netherlands.

METHODS

Participants were allocated to DMEK (n = 29) or UT-DSAEK (n = 25) using minimization randomization based on preoperative BSCVA, recipient central corneal thickness, gender, age, and institution. Donor corneas were prestripped and precut for DMEK and UT-DSAEK, respectively. Six corneal surgeons participated in this study.

MAIN OUTCOME MEASURES

The primary outcome measure was BSCVA at 12 months after surgery.

RESULTS

Central graft thickness of UT-DSAEK lamellae measured 101 μm (95% confidence interval [CI], 90-112 μm). Best spectacle-corrected visual acuity did not differ significantly between DMEK and UT-DSAEK groups at 3 months (0.15 logarithm of the minimum angle of resolution [logMAR] [95% CI 0.08-0.22 logMAR] vs. 0.22 logMAR [95% CI 0.16-0.27 logMAR]; P = 0.15), 6 months (0.11 logMAR [95% CI 0.05-0.17 logMAR] vs. 0.16 logMAR [95% CI 0.12-0.21 logMAR]; P = 0.20), and 12 months (0.08 logMAR [95% CI 0.03-0.14 logMAR] vs. 0.15 logMAR [95% CI 0.10-0.19 logMAR]; P = 0.06). Twelve months after surgery, the percentage of eyes reaching 20/25 Snellen BSCVA was higher in DMEK compared with UT-DSAEK (66% vs. 33%; P = 0.02). Endothelial cell density did not differ significantly 12 months after DMEK and UT-DSAEK (1870 cells/mm² [95% CI 1670-2069 cells/mm²] vs. 1612 cells/mm² [95% CI 1326-1898 cells/mm²]; P = 0.12). Both techniques induced a mild hyperopic shift (12 months: +0.22 diopter [D; 95% CI -0.23 to 0.68 D] for DMEK vs. +0.58 D [95% CI 0.13-1.03 D] for UT-DSAEK; P = 0.34).

CONCLUSIONS

Descemet membrane endothelial keratoplasty and UT-DSAEK did not differ significantly in mean BSCVA, but the percentage of eyes achieving 20/25 Snellen vision was significantly higher with DMEK. Endothelial cell loss did not differ significantly between the treatment groups, and both techniques induced a minimal hyperopic shift.

Descemet's Membrane Endothelial Keratoplasty with Split Corneal Grafts: The Influence of Tamponade Material and Endothelial Storage Time

Purpose: The aim of this study was to describe the clinical outcome of Descemet's membrane endothelial keratoplasty (DMEK) performed with split corneal grafts and to evaluate the influence of tamponade material and endothelial storage time on DMEK success. Material and Method: The records of 43 patients who underwent DMEK surgery with a split corneal graft were reviewed. Diagnosis of the patients, preoperative and postoperative best-corrected visual acuity (BCVA), corneal and endothelial storage time, tamponade material, complications, and success rates were specifically tabulated. Results: The most common indication for DMEK was pseudophakic bullous keratopathy (n = 25, 58.2%). Re-bubbling was needed in 10 cases (23.2%), and a re-DMEK was scheduled in 2 cases and penetrating keratoplasty in 4 cases (9.3%). BCVA improved significantly postoperatively (p < .001). There was an insignificant trend towards a lower re-bubbling rate and better long-term anatomic outcome in favor of 20% SF6 group compared to air tamponade (p = .18 and p = .25). There was no significant difference between the early endothelial transplant (<24 h) and delayed endothelial transplant (3 to 14 days) groups for anatomic success, corneal thickness or BCVA (p = .94, p = .13 and p = .35). Conclusion: The success rate of DMEK was satisfactory with split corneal grafts. There was no adverse influence of delayed endothelial transplantation on clinical outcome. The success rate of 20% SF6 tamponade was slightly better than room air.

Outcomes of Descemet Stripping Endothelial Keratoplasty in Eyes With Pars Plana Versus Anterior Chamber Glaucoma Drainage Devices

PURPOSE

To compare visual outcomes and complications of Descemet stripping endothelial keratoplasty (DSEK) in eyes with anterior chamber (AC) versus pars plana (PP) glaucoma drainage devices (GDDs).

METHODS

A retrospective chart review was conducted of 85 eyes that underwent DSEK and had previous or concurrent AC (37 eyes) or PP (48 eyes) GDD implantation. Outcome measures examined included visual acuity, donor dislocation rate, intraocular pressure, and secondary graft failure (SGF).

RESULTS

The mean logarithm of the minimum angle of resolution vision improved from 1.50 (SD = 0.64) to 0.88 (SD = 0.71) in the AC group and from 1.37 (SD = 0.59) to 1.20 (SD = 0.76) in the PP group, with no significant group difference. Intraocular pressure did not differ between the groups preoperatively but was higher in the AC group compared with the PP group postoperatively [mean (SD) 14.5 (6.28) versus 11.5 (5.54) mm Hg, P = 0.03]. Graft dislocation occurred in 35.1% and 29.2% of eyes in the AC and PP groups, respectively. SGF occurred in 18.9% and 41.7% with median time 17.1 (interquartile range [IQR] 4.6-32.1) and 27.9 (IQR 15.1-34.7) months to development in the AC and PP groups, respectively. Multivariable logistic and Cox proportional hazards regression models found no statistically significant factors (tube location, age, sex, concurrent tube revision, new tube insertion) associated with either donor dislocation or SGF.

CONCLUSIONS

There was no reduction in donor dislocation or SGF in eyes with PP compared with AC GDD, despite the decreased proximity of the shunt from the endothelial graft. Overall, GDD has a significantly adverse effect on long-term graft survival and close follow-up is warranted.

Surgery-induced iris abnormalities after Descemet membrane endothelial keratoplasty and their impact on postoperative clinical outcomes

Purpose: This study aimed to elucidate the frequency of surgery-induced iris abnormalities after Descemet membrane endothelial keratoplasty (DMEK) and their impact on postoperative clinical outcomes.

Methods: In this retrospective study, medical records of 32 eyes from 28 consecutive patients (mean age, 65.7±13.4 years; 14 men, 18 women) who underwent DMEK (or triple DMEK) were reviewed. In all patients, inferior peripheral iridectomy was created leaving full intracameral air tamponade at the end of surgery. Sulfur hexafluoride gas was not used in any cases. Surgery-induced iris abnormalities such as pupillary shape changes and iris depigmentation were evaluated by 3 masked observers. Pre-existing abnormalities were excluded. Eyes were divided into two groups based on the presence of surgery-induced iris changes: Group A (with iris abnormalities) and Group B (without). Impacts on postoperative clinical outcomes such as vision and endothelial cell density were analyzed.

Results: Surgery-induced iris abnormalities were seen in 15 eyes (Group A, 9 with pupillary shape change and 6 with iris depigmentation; 46.9%), and 17 eyes showed no abnormalities (Group B, 53.1%). No significant differences were detected between groups in age, sex, indication, simultaneous cataract surgery, pre- and 6-month postoperative vision, donor age, donor endothelial cell density, and 6- and 12-month postoperative endothelial cell density.

Conclusions: Surgery-induced iris abnormalities were noted in almost half of the eyes after DMEK (46.9%) in this study. However, there was no association between visual outcomes or postoperative endothelial cell density and the iris changes.