Graft Detachment Pattern After Descemet Membrane Endothelial Keratoplasty Comparing Air Versus 20% SF6 Tamponade

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.

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.

Video Grading of Descemet Membrane Endothelial Keratoplasty Surgery to Identify Surgeon Risk Factors for Graft Detachment and Rebubbling: A Post Hoc Observational Analysis of the Advanced Visualization In Corneal Surgery Evaluation Trial

PURPOSE

The aim of this study was to explore video-graded intraoperative risk factors for graft detachment (GD) and rebubbling in Descemet membrane endothelial keratoplasty surgery.

METHODS

A post hoc analysis of 65 eyes of 65 pseudophakic subjects with Fuchs endothelial dystrophy that underwent Descemet membrane endothelial keratoplasty surgery as part of the Advanced Visualization In Corneal Surgery Evaluation trial. All surgical recordings were assessed by 2 graders using a structured assessment form. A multinominal regression was performed to estimate the independent effect of video-graded intraoperative factors on the incidence of GD and rebubbling. Secondary outcomes are corrected distance visual acuity and endothelial cell density.

RESULTS

In total, 33 GDs were recorded, of which 17 required rebubbling. No significant predictors for GD or rebubbling were identified. However, the results revealed 2 clinically relevant patterns. An unfavorable graft configuration (ie, wrinkled, tight scroll, or taco-shaped) and a gas-bubble size smaller than the graft diameter were associated with an increased risk of GD [odds ratio (OR) 2.5 and OR 2.26, respectively] and rebubbling (OR 2.0 and OR 2.60, respectively). Inversely, a larger gas-bubble size was associated with a reduced risk of GD (OR 0.37) and rebubbling (OR 0.36). At 3 and 6 months postoperatively, corrected distance visual acuity was poorer in subjects requiring a rebubbling and endothelial cell density loss was higher in subjects with a partial GD.

CONCLUSIONS

Our analysis revealed that the gas-bubble size and graft shape/geometry seem to be relevant clinical factors for GD and rebubbling, whereas descemetorhexis difficulty, degree of graft manipulation, graft overlap, and surgical iridectomy were not associated with an increased risk.

Rate of Endothelial Cell Loss and Graft Survival in Descemet Membrane Endothelial Keratoplasty in Eyes Requiring a Rebubble

PURPOSE

We aimed to compare the rate of 6-month endothelial cell loss (ECL) and 6-month graft survival in eyes that did not require a postoperative rebubble with eyes that did require a postoperative rebubble after Descemet membrane endothelial keratoplasty (DMEK) surgery.

METHODS

A consecutive series of DMEK surgeries performed from September 2013 to March 2020 was retrospectively analyzed. Eyes that did not require a rebubble for graft detachment were compared with eyes with 1 rebubble and eyes with 2 or more rebubbles for 6-month ECL and graft survival. A subanalysis of the rebubble rate for different indications for transplantation was also performed.

RESULTS

One thousand two hundred ninety-eight eyes were included in this study. The 6-month ECL for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 29.3% ± 16.2% (n = 793), 36.4% ± 18.6% (n = 97, P = 0.001), and 50.1% ± 19.6% (n = 28, P < 0.001), respectively. The 6-month graft survival rate for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 99.5%, 97.8% ( P = 0.035), and 81.8% ( P < 0.001), respectively. When compared to the rebubble rate for DMEK for Fuchs dystrophy (156/1165 eyes = 13.4%), the rebubble rates were statistically higher for DMEK for failed penetrating keratoplasty (28.5%, P = 0.021) and pseudophakic bullous keratopathy (28.0%, P = 0.036).

CONCLUSIONS

Eyes undergoing any rebubble procedure in the postoperative period after DMEK have an increased risk of endothelial cell loss and graft failure at 6 months postoperative. DMEK in eyes for failed penetrating keratoplasty and failed DMEK had the highest rebubble rate, with the former reaching statistical significance.

Transferability of an Artificial Intelligence Algorithm Predicting Rebubblings After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To develop an artificial intelligence (AI) algorithm enabling corneal surgeons to predict the probability of rebubbling after Descemet membrane endothelial keratoplasty (DMEK) from images obtained using optical coherence tomography (OCT).

METHODS

Anterior segment OCT data of patients undergoing DMEK by 2 different DMEK surgeons (C.C. and B.B.; University of Cologne, Cologne, Germany) were extracted from the prospective Cologne DMEK database. An AI algorithm was trained by using a data set of C.C. to detect graft detachments and predict the probability of a rebubbling. The architecture of the AI model used in this study was called EfficientNet. This algorithm was applied to OCT scans of patients, which were operated by B.B. The transferability of this algorithm was analyzed to predict a rebubbling after DMEK.

RESULTS

The algorithm reached an area under the curve of 0.875 (95% confidence interval: 0.880-0.929). The cutoff value based on the Youden index was 0.214, and the sensitivity and specificity for this value were 78.9% (67.6%-87.7%) and 78.6% (69.5%-86.1%).

CONCLUSIONS

The development of AI algorithms allows good transferability to other surgeons reaching a high accuracy in predicting rebubbling after DMEK based on OCT image data.

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.

Posterior stromal ripples increase risk of Descemet's membrane endothelial keratoplasty graft detachment worsening over time

PURPOSE

To evaluate anterior segment optical coherence tomography (AS-OCT) features of Descemet's membrane endothelial keratoplasty (DMEK) grafts associated with graft attachment worsening over time.

METHODS

Retrospective case series on patients who received uncomplicated DMEK surgery and for whom subsequent AS-OCT data were available for analysis. Patients' demographics and surgical details were collected. AS-OCT was analysed for graft detachment axial extension, presence of posterior stromal ripples, quadrant involvement (location and number), degree of detachment extension, peripheral roll, presence and amount of air in the anterior chamber (AC). Features associated with re-bubbling and graft detachment worsening over time were identified.

RESULTS

A total of 147 patients with a mean age of 70.8 ± 9.8 years (63% females) were included. AS-OCT was performed at 2.9 ± 2.4 days after surgery. AS-OCT factors associated with re-bubbling were posterior stromal ripples (p = 0.004) and detachment axial extension (p < 0.001). At first follow-up, of the 147 DMEK, 67 showed complete attachment and 80 partial detachment. In those cases of initially completely attached grafts, posterior stromal ripples were associated with the risk of subsequent graft detachment (p = 0.014) together with recipient age (p = 0.043), phaco-combined surgery (p = 0.018) and AS-OCT timing (p = 0.033); while, in the initially partially detached grafts, detachment worsening was associated with posterior stromal ripples (p = 0.025), detachment axial extension (p = 0.003), degrees of detachment involvement (p = 0.029), peripheral roll-in shape (p = 0.033) and presence of air in the AC (p = 0.032). Relative risk (RR) of graft detachment worsening in patients with moderate/severe posterior stromal ripples was 1.75 (95% CI = 1.09-2.81).

CONCLUSION

Posterior stromal ripples and detachment axial extension >1/3 of graft surface area were the main risk factors for detachment worsening over time, and patients showing these features should be monitored closely to identify the need for re-bubbling at an early stage, thus improving surgical outcomes.

The need of rebubbling in case of small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK)

Purpose

To investigate the need of rebubbling for small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK).

Methods

In this retrospective study we evaluated 111 eyes from 111 patients that showed graft detachment after DMEK surgery and have achieved graft adherence by injection of air or 20% sulfur hexafluoride (SF6) to the anterior chamber (rebubbling group; n = 57) or by spontaneous adherence without intervention (control group; n = 54) at final examination. Subgroups in terms of the maximum height and in terms of the detachment area in relation to graft area were formed. Outcome measures were the increase in best-corrected visual acuity (BCVA) and the decrease in central corneal thickness (CCT) from the measurement before DMEK to six months after surgery and postoperative endothelial cell density.

Results

BCVA increased in the rebubbling group and the control group, the difference being 0.22 logMAR, p = 0.048. For eyes with a maximum height less than 500  µm, the increase of BCVA was 0.39 ± 0,36 logMAR in the control group and 0.62 ± 0,53 logMAR in the rebubbling group, p = 0.045. There was no difference of statistical significance of BCVA between both groups regarding the detachment area of less than 20% in relation to graft area. The mean decrease in CCT and postoperative endothelial cell density showed no significant difference between the rebubbling group and the control group.

Conclusion

Compared to spontaneous graft adherence, a rebubbling shows no beneficial effect on the clinical outcome for small detached DMEK grafts. Rebubbling does not decrease postoperative endothelial cell density.

Predictive factors of graft detachment and rebubbling after descemet membrane endothelial keratoplasty

PURPOSE

To identify risk and predictive factors associated with the need of rebubbling in the eye of patients who underwent a descemet membrane endothelial keratoplasty (DMEK).

METHODS

The records of patients who underwent DMEK were retrospectively analyzed. Data regarding comorbidities, intraoperative characteristics, and postoperative treatments or complications were collected. The central corneal thickness (CCT) was measured by optical coherence tomography before and the day after DMEK. Univariate and multivariate analyses were performed.

RESULTS

Of the 333 DMEK, rebubbling was performed in 119 cases (36%). Preoperative subepithelial fibrosis and a history of penetrating keratoplasty (PK) were associated with significantly more graft detachment [OR of 3.55 (2.02-6.32; P < 0.001) and 5.89 (2.00-21.86; P = 0.003), respectively]. A decreased CCT the day after surgery reduced by 5.7-fold the risk of rebubbling (sensitivity/specificity of 0.42/0.93). Conversely, a 20% increase in the CCT the day after surgery increased by 4.5-fold the risk of rebubbling (sensitivity/specificity of 0.42/0.91).

CONCLUSION

Variation of the CCT could be used as a predictive factor of rebubbling after DMEK. Patients with a 20% increase of CCT the day after surgery are at higher risk of graft detachment. Conversely, a reduced CCT the day after the surgery is associated with a reduced risk of rebubbling. Subepithelial fibrosis and history of PK were also identified as risk factors for rebubbling. Those predictive factors may help develop a customized approach for patients undergoing DMEK surgery.

Graft Detachment after Descemet Membrane Endothelial Keratoplasty with and without Cataract Surgery

PURPOSE

To evaluate graft detachment after Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes and DMEK combined with cataract surgery (triple DMEK).

DESIGN

Analysis of 3 single-center prospective cohort studies and 1 randomized controlled trial.

PARTICIPANTS

Participants with Fuchs' endothelial corneal dystrophy.

METHODS

A validated neural network for image segmentation quantified graft detachment on anterior segment OCT (AS-OCT) images 3 days after DMEK and at the 2-week postoperative visit. Area and volume of graft detachment were compared between DMEK only and triple DMEK using generalized estimating equation models and adjusting for participant age and the size of the air bubble.

MAIN OUTCOME MEASURES

Area and volume of DMEK graft detachment.

RESULTS

Among 207 participants with 270 eyes included, 75 pseudophakic eyes had DMEK only and 195 eyes had triple DMEK. A total of 147 eyes had less than one third of detachment at day 3. In 139 of these eyes (95%), detachment was still less than one third at the 2-week scan, indicating that postoperative graft detachment at 2 weeks occurred mainly in eyes with early detachment. When superimposing all 3-dimensional maps from 2 weeks after surgery, the central graft was mainly attached and detachment was located at the graft margin. The mean area of graft detachment decreased from 28% in DMEK only and 38% in triple DMEK to 16% in DMEK only and 25% in triple DMEK at the 2-week postoperative visit. At 2 weeks, the mean area of detachment was 1.85-fold higher (95% confidence interval [CI], 1.34-2.56) and the mean volume was 2.41-fold higher (95% CI, 1.51-3.86) in triple DMEK compared with DMEK. A total of 46 eyes received rebubbling procedures, with 7 eyes (9%) in the DMEK group and 39 eyes (20%) in the triple DMEK group (adjusted risk ratio, 3.1; 95% CI, 1.3-7.1), indicating that rebubbling was more common in eyes undergoing triple DMEK.

CONCLUSIONS

Automated segmentation of AS-OCT images allowed precise quantification of graft detachment over time and identified DMEK combined with cataract surgery as a risk factor. Frequency of operative follow-up might be guided by extent of detachment in the first postoperative days after DMEK.

A machine learning approach to explore predictors of graft detachment following posterior lamellar keratoplasty: a nationwide registry study

Machine learning can be used to explore the complex multifactorial patterns underlying postsurgical graft detachment after endothelial corneal transplantation surgery and to evaluate the marginal effect of various practice pattern modulations. We included all posterior lamellar keratoplasty procedures recorded in the Dutch Cornea Transplant Registry from 2015 through 2018 and collected the center-specific practice patterns using a questionnaire. All available data regarding the donor, recipient, surgery, and practice pattern, were coded into 91 factors that might be associated with the occurrence of a graft detachment. In this research, we used three machine learning methods; a regularized logistic regression (lasso), classification tree analysis (CTA), and random forest classification (RFC), to select the most predictive subset of variables for graft detachment. A total of 3647 transplants were included in our analysis and the overall prevalence of graft detachment was 9.9%. In an independent test set the area under the curve for the lasso, CTA, and RFC was 0.70, 0.65, and 0.72, respectively. Identified risk factors included: a Descemet membrane endothelial keratoplasty procedure, prior graft failure, and the use of sulfur hexafluoride gas. Factors with a reduced risk included: performing combined procedures, using pre-cut donor tissue, and a pre-operative laser iridotomy. These results can help surgeons to review their practice patterns and generate hypotheses for empirical research regarding the origins of graft detachments.

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.

[Morphological characteristics of Descemet's membrane removed during endothelial keratoplasty (case study)]

The two most used modifications of endothelial keratoplasty (EK) are Descemet's membrane endothelial keratoplasty (DMEK) and Descemet's stripping automated endothelial keratoplasty (DSAEK). The leading complication of EK surgeries is graft detachment in the early postoperative period. This article reports on two cases of endothelial graft adhesion depending on morphological characteristics of the Descemet's membrane (DM) removed during EK. In the first case, complete graft attachment to the recipient's posterior stroma was observed after DMEK. Morphological analysis of the DM showed clean stromal surface. In the second case there was a false chamber between the endothelial transplant and the posterior stroma of the patient. OCT scans revealed separate stromal fibers protruding into the false chamber; morphological analysis of the removed DM showed stromal fragments fixed to the anterior surface of the DM. The revealed changes indicate damage to the posterior stroma the suffered received during descemetorhexis, which may be the cause for incomplete graft attachment. Complete attachment after repeated EK (DSAEK) in this case was due to a thin stromal layer on the graft that provided high degree of adhesion to the posterior corneal surface. DSAEK can be indicated as a repeated EK surgery in cases of persistent endothelial graft non-attachment after DMEK.

Comparison of Mini-DMEK versus predescemetal sutures as treatment of acute hydrops in keratoconus

PURPOSE

To compare two surgical treatment options for acute corneal hydrops in keratoconus: Mini-DMEK versus predescemetal sutures.

METHODS

Sixteen patients were treated by either Mini-Descemet membrane endothelial keratoplasty (Mini-DMEK) (n = 7, group 1) or predescemetal sutures (n = 9, group 2) early after onset of acute hydrops. Visual acuity, maximum corneal thickness (SD-OCT) in the affected oedematous area, complications and recurrence rates were retrospectively compared between both groups. Measurements were taken immediately preoperatively as well as 1 day, 1 week and 1 month postoperatively (Table 1).

RESULTS

Both groups showed reductions in corneal thickness and increased visual acuity shortly after surgery. In group 1 (average age 33 years ± 7 years), the best corrected visual acuity (BCVA) increased from logMAR 1.65 ± 0.7 before Mini-DMEK to logMAR 0.93 ± 0.6 30 days after Mini-DMEK (p = 0.046). During that period, maximum corneal thickness decreased from 1159 ± 338 µm before surgery to 531 ± 75 µm after Mini-DMEK (p = 0.046). Patients from group 2 (average age 34 ± 10 years) had a BCVA of logMAR 1.59 ± 0.8 which increased to logMAR 0.97 ± 0.5 (p = 0.014) 30 days after surgery. At the same time, the preoperative maximum corneal thickness decreased from 1439 ± 272 µm to 476 ± 162 µm (p = 0.014). There was no difference in corneal thickness or BCVA one month after the surgical intervention between both groups (p = 0.394 and p = 0.871).

CONCLUSIONS

Both techniques, Mini-DMEK and predescemetal sutures, are effective in the treatment of an acute hydrops in keratoconus. Mini-DMEK appears to be beneficial in large DM tears.

Rotational alignment of corneal endothelial grafts and risk of graft detachment after Descemet membrane endothelial keratoplasty: a double-masked pseudo-randomized study

PURPOSE

The posterior cornea is rotationally asymmetric, and Descemet membrane endothelial keratoplasty (DMEK) grafts preferentially scroll vertically. This prospective study assessed whether graft attachment after DMEK differed depending on the rotational alignment of the donor graft in the recipient eye.

METHODS

Pseudo-randomization and blinding of the graft orientation in the recipient's eye were possible by procedural separation: (1) The eye bank recorded the position of an orientation marker in the donor cornea; (2) the surgeon preparing the DMEK graft recorded an upside-down marker relative to the eye bank marker; and (3) the surgeon assessed the position of the upside-down marker in the recipient after DMEK. Surgeons were masked towards the eye bank marker. Using mixed-effects models, we assessed graft attachment relative to the rotational alignment of the donor graft.

RESULTS

Postoperatively, the graft was not fully attached in 59 of 179 eyes (33%). A second air fill (rebubbling) was performed in 11%. The graft axis was in line with the recipient cornea axis in 40%, oblique in 28% and orthogonal in 32%. We did not detect an elevated risk of incomplete attachment (odds ratio [OR], 1.16; 95% CI, 0.61-2.20), risk of rebubbling (OR, 1.25; 95% CI, 0.47-3.31) or larger areas of graft detachment in non-aligned grafts compared to aligned grafts.

CONCLUSION

Rotational alignment was not strongly associated with the risk of incomplete graft attachment, although modestly elevated risks cannot be ruled out. Efforts are needed to reduce the need for rebubbling after DMEK and to identify modifiable risk factors for graft detachment.

Outcomes of Pseudophakic, Phakic, and Triple DMEK

PURPOSE

To evaluate the outcome of phakic and pseudophakic eyes treated by Descemet membrane endothelial keratoplasty (DMEK) versus DMEK combined with cataract surgery (triple DMEK).

METHODS

Retrospective cohort study based on the prospective Cologne DMEK data base. This study is a single-center analysis of 62 eyes undergoing phakic (age mean ± SD 52 ± 6.43), 518 eyes undergoing pseudophakic (73.5 ± 8.57), and 557 eyes undergoing triple DMEK (67.93 ± 8.57). Outcome measures were changes in best spectacle-corrected visual acuity (BSCVA), central corneal thickness, endothelial cell density (ECD), rebubbling rates within the first year after surgery, and the need for cataract surgery within the first 2 years after phakic DMEK.

RESULTS

The preoperative BSCVA (mean ± SD; logarithm of the minimum angle of resolution) was 0.30 ± 0.22 in the phakic, 0.63 ± 0.45 in the pseudophakic, and 0.44 ± 0.30 in the triple DMEK group (P < 0.001), which changed to 0.09 ± 0.12, 0.14 ± 0.1, and 0.1 ± 0.1 (P < 0.001) 1 year after surgery, respectively. There was no difference in central corneal thickness (P = 0.929) and endothelial cell density (P = 0.606) 1 year postoperatively. Rebubbling rates in DMEK using SF6 20% for anterior chamber tamponade were not significantly different (P = 0.839). After phakic DMEK, 40% of eyes underwent cataract surgery within the second year. However, there was a high loss to follow-up in this group.

CONCLUSIONS

Phakic and triple DMEK procedures tend to have a better 1-year BSCVA than pseudophakic DMEK, with no differences in all other parameters analyzed. However, patients from the pseudophakic DMEK group were older and already had worse BSCVA before surgery.

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>.

Impact of Early Intraocular Pressure Elevation on Postoperative Outcome After Descemet Membrane Endothelial Keratoplasty in Non-glaucoma Patients

PURPOSE

The purpose of this study was to investigate the impact of transient elevations in postoperative intraocular pressure (IOP) on the clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) surgery in non-glaucoma patients.

METHODS

Retrospective analysis from a prospective database of eyes without preexisting glaucoma that underwent DMEK with 90% anterior chamber and 20% sulfur hexafluoride endotamponade. Group A included eyes without postoperative IOP increase (IOP <30 mm Hg and a relative increase from preoperative value <10 mm Hg). Group B included eyes with IOP elevation (postoperative IOP ≥30 mm Hg or a relative increase from preoperative value ≥10 mm Hg) handled according to a standardized protocol. The impact of elevated IOP within 3 days after DMEK surgery was evaluated regarding best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell count (ECC) at 1, 3, and 6 months.

RESULTS

One hundred seventy-six eyes from 164 patients were included. An IOP increase after DMEK occurred in 20 eyes (11.3%; 19 patients, group B), and the mean peak IOP was 48 ± 12 mm Hg (range 32-69 mm Hg). There were no significant postoperative differences in BCVA, CCT, and ECC on comparing both groups. The BCVA increased significantly (P < 0.001, respectively), whereas CCT (P < 0.001, respectively) and ECC (P < 0.001, respectively) decreased significantly from preoperative values. The rebubbling rate tended to be higher in group B without statistical significance (6.4% vs. 10%, P = 0.648).

CONCLUSIONS

Temporary IOP elevation after DMEK may not affect functional and morphological outcomes in non-glaucoma patients. However, careful postoperative IOP monitoring and appropriate management are crucial to avoid irreversible ocular damage.

Graft detachments in endothelial keratoplasty

Graft detachment is the most common complication of endothelial keratoplasty. With the ongoing advancements in the field of endothelial keratoplasty, our understanding of risk factors of graft detachments and its management has been evolving. Various prevention measures have been described in literature including presoaking the donor graft, anterior chamber tamponade, venting incisions, sutures to prevent dislocation of graft. Management of a detached graft involves secondary interventions such as rebubbling, suturing and regrafts. In this review, we discuss graft detachment in different types of endothelial keratoplasty techniques including Descemet stripping endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and Descemet's membrane endothelial keratoplasty; with emphasis on incidence, risk factors, preventive measures and their management.

The Cologne rebubbling study: a reappraisal of 624 rebubblings after Descemet membrane endothelial keratoplasty

Background/Aims

To analyse graft detachments prior to rebubbling, the influence of rebubbling on the postoperative outcome after Descemet membrane endothelial keratoplasty (DMEK) and the need for rebubbling on the contralateral eye.

Methods

In this retrospective cohort study, out of 1541 DMEKs, optical coherence tomography scans and clinical records of 499 eyes undergoing rebubbling after DMEK at the University Hospital of Cologne, Cologne, Germany, were examined. Main Outcome measures were (a) number, localisation and size of graft detachments; (b) influence of rebubbling/s on postoperative outcome after 12 months; and (c) rebubbling risk of the contralateral eye after DMEK.

Results

Mean number of detachment areas was 2.02±0.9. Mean lateral diameter of all detachments was 4534.76±1920.83 μm. Mean axial diameter was 382.53±282.02 μm. Detachments were equally distributed over all regions of the cornea. Best spectacle corrected visual acuity ( BSCVA) after 12 months was 0.197±0.23 logarithm of the minimum angle of resolution, endothelial cell density (ECD) was 1575.21±397.71 cells/mm2and mean central corneal thickness (CCT) was 566.37±68.11 μm. BSCVA, CCT, ECD or endothelial cell loss of all rebubbled patients were not influenced by the number of rebubblings or the time between DMEK and rebubbling. Of the rebubbled patients, which received a DMEK subsequently on the other eye, 193 (58.8%) also received a rebubbling, which was significantly higher, when compared to the overall rebubbling rate of 32.3% (p=0.000).

Conclusions

The overall number of rebubblings has no influence on the postoperative outcome after DMEK, if a rebubbling becomes necessary. Patients who received a rebubbling on one eye have an elevated risk for a rebubbling on the fellow eye.

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.

Parameters Associated With Endothelial Cell Density Variability After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To evaluate which parameters may affect endothelial cell loss after Descemet membrane endothelial keratoplasty (DMEK) by comparing eyes in the low vs high quartile of endothelial cell loss over a follow-up period of 4 years.

DESIGN

Retrospective cohort study.

METHODS

Donor endothelial cell density (ECD) decline was evaluated for 351 eyes of 275 patients up to 4 years after DMEK for Fuchs endothelial corneal dystrophy (FECD). Eyes with a postoperative endothelial cell loss in the lower quartile at all available follow-up moments were assigned to Group 1 (n = 51) and those in the upper quartile to Group 2 (n = 42). Multinomial regression was used to assess which covariates were related to greater ECD decline.

RESULTS

Mean endothelial cell loss as compared to preoperative donor ECD for the entire study group was 33 (±16)%, 36 (±17)%, and 52 (±18)% at 1, 6, and 48 months postoperatively. Endothelial cell loss of Group 1 was 12 (±7)%, 13 (±6)%, and 26 (±8)% at, respectively, 1, 6, and 48 months postoperatively, and 59 (±10)%, 64 (±9)%, and 75 (±5)% in Group 2. Partial graft detachment, donor death cause cardiovascular/stroke (vs cancer), postoperative complications other than graft detachment, and severity of preoperative FECD (all P < .01) showed the strongest relation with greater ECD decline.

CONCLUSIONS

DMEK eyes with a completely attached graft and operated in an early stage of FECD may show the lowest endothelial cell loss postoperatively.

Mini-Descemet Membrane Endothelial Keratoplasty for the Early Treatment of Acute Corneal Hydrops in Keratoconus

PURPOSE

To describe a new surgical option for the treatment of acute corneal hydrops in keratoconus and to present the first results.

METHODS

This is a retrospective analysis of 3 patients who presented to our clinic with a massive corneal hydrops in acute keratoconus and were treated by mini-Descemet membrane endothelial keratoplasty (DMEK). According to the size and the shape of the gap in the patient's Descemet membrane (DM), 1 DMEK graft was trephined with a round 5-mm punch. The other grafts were trimmed with a razor blade to a width of about 3 mm and a length adjusted to the length of the defect of the recipients' DM. The graft was inserted with a regular intraocular lens shooter. Correct unfolding of the graft was controlled by using intraoperative optical coherence tomography. At the end of the surgery, the graft was attached to the posterior corneal surface by a small air bubble. Thereafter, the complete anterior chamber was filled with 20% SF6 gas.

RESULTS

All 3 patients (age 32 ± 3 years on average) showed a rapid increase in uncorrected visual acuity from the logarithm of the minimum angle of resolution (LogMAR) 1.66 (±0.46) before mini-DMEK to the LogMAR 1.2 (±0.3) within 6 to 8 weeks after mini-DMEK. The thickest corneal point within the edematous cornea decreased in all 3 patients (1088 ± 280 μm before surgery vs. 630 ± 38 μm 1 week after surgery). One mini-DMEK failed in a first attempt. In this patient, the recipient DM was under strong tension and showed a pronounced dehiscence. Therefore, a small part of the recipient's DM around the preexisting gap in DM was removed before a second mini-DMEK graft was placed successfully. The other 2 patients developed partial graft detachment within 1 to 2 weeks after surgery. However, the corneas of these patients were dehydrated to physiological levels after mini-DMEK, and despite partial detachment, there was no relapse of the hydrops.

CONCLUSIONS

Mini-DMEK could be helpful in patients with larger defects and detachments of DM in very ectatic corneas in the acute phase of corneal hydrops in acute keratoconus. These patients may not be successfully treated by intracameral gas application alone or in combination with pre-Descemetal sutures. Further investigations are needed to identify factors helping to decide on the best surgical approach in hydrops in acute keratoconus.

Microscope-Integrated Optical Coherence Tomography-Guided Drainage of Acute Corneal Hydrops in Keratoconus Combined With Suturing and Gas-Aided Reattachment of Descemet Membrane

PURPOSE

The treatment of acute corneal hydrops due to keratoconus has so far been limited to awaiting the spontaneous resorption of corneal edema, supportive care, and finally keratoplasty. A recent publication describes the surgical reattachment of Descemet Membrane (DM) facilitated by pre-Descemetic sutures and anterior chamber air/gas filling. Here, we present a novel microscope-integrated intraoperative optical coherence tomography (MI-OCT)-guided technique for the immediate reattachment of DM in corneal hydrops due to keratoconus in 2 male patients with small central DM defects.

METHODS

Case series of 2 consecutive patients with acute corneal hydrops due to keratoconus. The novel technique consists of the MI-OCT-guided puncture and drainage of intrastromal fluid pockets combined with anterior chamber sulfur hexafluoride-fill and pre-descemetic sutures using a commercially available MI-OCT (iOCT; Haag Streit Surgical, Wedel, Germany).

RESULTS

After uneventful surgery, corneal edema showed fast resolution and DM was reattached to the corneal stroma. In both patient's central corneal thickness decreased after surgery and visual acuity improved.

CONCLUSIONS

MI-OCT guided micropuncture of stromal edema combined with compression sutures and SF6 tamponade is a new therapeutic option in acute corneal hydrops with small Descemet membrane defects.

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.

[10 years of Descemet membrane endothelial keratoplasty in Fuchs endothelial corneal dystrophy : What have we learned?]

BACKGROUND AND OBJECTIVE

Descemet membrane endothelial keratoplasty (DMEK) has increased in popularity since its introduction over 10 years ago. This article presents a summary of the experiences of the past years collected at the Department of Ophthalmology at the University of Cologne.

METHODS

A literature review of DMEK studies primarily from the Department of Ophthalmology at the University of Cologne, Germany was carried out. Own experiences in the fields of donor selection and graft preparation, DMEK surgery, complication management and postoperative treatment are summarized.

RESULTS

Since the introduction of DMEK experience has been gained and ongoing improvements have occurred ranging from donor-recipient allocation to postoperative follow-up. These led to a better reproducibility of the intervention for the surgeon, to a better postoperative result and to a reduction of the complication rate.

DISCUSSION

The DMEK represents a safe and individualized procedure for endothelial transplantation for corneal endothelial dysfunction. Continuing development of the method leads to optimization and safer results.