Membrane Endothelial Keratoplasty Research Articles

Novel Trephine for Descemet Membrane Endothelial Keratoplasty Surgery Improves Surgical Preparation Time and Graft Quality: Pilot Data From the "Number 7" Endothelial Keratoplasty Trephine.

To report the safety and efficacy of a novel asymmetric marking trephine for Descemet membrane endothelial keratoplasty (DMEK) tissue preparation. The trephine design incorporates optimized curves to distribute mechanical forces and minimize the risk of tears without loss of total endothelial cell volume transplanted compared with a standard 8.00 mm circular transplant. A retrospective case series of 40 consecutive DMEK operations comparing 20 cases using the "Number 7" trephine against 20 using a modified shark fin technique as standard. Patient and donor characteristics, tissue preparation time and complications, total surgical time, intraoperative and postoperative complications, and endothelial cell counts at 3 months postsurgery are reported. DMEK tissue preparation was significantly faster using the "Number 7" trephine (5.4 vs. 7.6 minutes, P = 0.008). Further, fewer complications arose during tissue preparation (0 vs. 2 complications) despite the faster preparation time. Total surgical time was similar between techniques; however, time spent manipulating the graft was reduced (5.1 vs. 6.8 minutes, P = 0.007) primarily because of the lower tissue preparation complications. Fewer postoperative complications were observed (1 vs. 3, of which 1 in the standard technique group requiring a redo-DMEK), again due to the reduced tissue preparation complications. The 3-month endothelial cell count was comparable between techniques (P > 0.05). Use of the "Number 7" trephine led to faster and safer DMEK tissue preparation, which in turn reduced graft manipulation times and postoperative complications without compromising total endothelial cell volume transplanted. This novel device is ideal for use by surgeons who prepare their own DMEK tissue and within tissue banks who provide prestripped and preloaded DMEK tissue.

Splenectomy as a Risk Factor for Graft Rejection Following Endothelial Transplantation: Retrospective Study.

Anterior chamber-associated immune deviation (ACAID) is an active immunotolerance mechanism, which is induced by placing antigen into the anterior eye chamber as long as a major surgical trauma is avoided. For this reason, ACAID may be a major contributor to the favorable immunologic outcomes in Descemet membrane endothelial keratoplasty (DMEK). Rodent models have demonstrated the importance of a functional spleen for the development of an ACAID. This study aimed to investigate whether splenectomy leads to increased rejection rates after DMEK in humans. A retrospective evaluation was conducted on the course following DMEK at the Eye Center, Medical Center, University of Freiburg, for patients with a self-reported history of splenectomy compared to patients without this condition. Potential study patients were contacted by mail. A questionnaire to self-report splenectomy and the time thereof was sent out. The medical records of all consenting patients at the Eye Center were reviewed for graft survival and immune reactions. We asked 1818 patients after DMEK to report their history of splenectomy. A total of 1340 patients responded and were included in the study. Of these 1340 patients, 16 (1.2%) reported a history of splenectomy (ie, 26 DMEKs, with 10 patients being transplanted in both eyes and 6 patients being transplanted in 1 eye; median age at surgery 73.7, range 66.7-76.1 y). The remaining patients (1324 patients, ie, 1941 eyes) served as controls, with 1941 DMEKs (median age at surgery 71.5, range 64.1-77.2 y). Five (19%) out of the 26 eyes from the splenectomy group required a second transplant due to dislocation (n=2.8%), failure (n=2.8%), and rejection (n=1.4%). Kaplan-Meier analysis revealed no relevant difference compared with controls. Our results suggest that splenectomy has no major effect on the outcome following DMEK. Subsequent, ACAID may not be the main reason for the favorable immunological outcomes in DMEK, or the camero-splenic axis may be subordinate in humans. However, we only included 16 patients who underwent splenectomy, so it might be possible that we missed a minor effect.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty for Iridocorneal Endothelial Syndrome With a Glaucoma Drainage Device.

The purpose of this study was to evaluate the feasibility and clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) for treating iridocorneal endothelial (ICE) syndrome with a glaucoma drainage device (GDD). In this retrospective, interventional case series, data of ICE eyes with a GDD treated with DMEK were collected at the Zhongshan Ophthalmic Center. A total of 24 patients (24 eyes) with mild-to-moderate ocular anterior segment anomalies together with good intraocular pressure (IOP) control preoperatively were included between March 10, 2014, and November 11, 2021. Cases were performed DMEK with concomitantly procedures, such as goniosynechialysis, an entire recipient's Descemet stripping, trimming of glaucoma tubes, and an inferiorly peripheral iridotomy. Graft survival, corrected distance visual acuity (CDVA), endothelial cell loss, IOP, and surgical complications were documented. The mean length of follow-up after surgery was 30.8 ± 7.8 months. Postoperative CDVA improved significantly. At 1 and 2 years postoperatively, 10 (50%) of 20 eyes and 7 (47%) of 15 eyes achieved a CDVA of 20/32 or better, cumulative graft success rates by Kaplan-Meier survival analysis were 89% and 67%, and endothelial cell loss were (59 ± 10)% and (71 ± 7)%, respectively. Within the follow-up period, IOP elevation and progressive peripheral anterior synechiae occurred in 7 (29%) and 5 (21%) of 24 eyes, respectively. With specific technical modifications, DMEK had not increased the risk of postoperative complications and provided comparable clinical outcomes in the treatment of ICE eyes with a GDD with those observed in the treatment of ICE eyes without a GDD.

The progress and future of corneal endothelial transplantation.

Endothelial transplantation has recently been accepted worldwide, in the long history of corneal transplantation. The introduction of endothelial keratoplasty (Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty) has enabled us to expand the surgical indications owing to the low incidence of rejection and quick recovery of visual function. New technologies have been developed to ensure stable postoperative outcomes with a shorter learning curve, such as transplantation using cultured human endothelial cells and induced pluripotent stem cells (iPS) or new devices such as artificial endothelium. This review discusses the history and characteristics of corneal transplantation alongside new treatment options that may offer hope for patients with endothelial disease in the future.

Determining Risk Factors for Detachment After Endothelial Keratoplasties: Nine-Year Review of a Single Institution.

To determine roles of patient history, donor tissue characteristics, tissue preparation methods, and surgeon technique for graft detachment requiring rebubbling after Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) procedures. Retrospective analysis of all eyes undergoing first-time DSAEK or DMEK at the study institution between 2013 and 2022. Data were collected regarding recipients' history, donors' medical history, tissue preparation methods, intraoperative details, and postoperative clinical outcomes. Multivariate statistical analysis was conducted to identify risk factors for graft detachment necessitating rebubbling. Of 1240 eyes meeting inclusion criteria, 746 (60.2%) underwent DSAEK, and 494 (39.8%) underwent DMEK. DSAEK procedures had 12.5% rebubbling rate, whereas DMEK procedures had 18.4% rebubbling rate (P = 0.005). Sub50-DSAEK (<50 μm) grafts had 16.0% rebubble rate, whereas sub100-DSAEK (51-99 μm) and >100 μm DSAEKs had rebubble rate of 9.9% and 9.5%, respectively (P = 0.006). Significant risk factors for DSAEK graft detachment included history of retinal surgery (OR = 2.59), preloaded tissue (OR = 2.70), forceps insertion (OR = 2.33), use of sub50-DSAEK lenticules versus sub100-DSAEK (OR = 2.44) and >100 μm DSAEK (OR = 2.38) lenticules, and donor history of noninsulin-dependent diabetes mellitus (OR = 4.18). DMEK risk factors included recipient history of cancer (OR = 2.51) and use of higher SF6 gas concentration (OR = 1.09). Although rebubbled DMEK eyes had comparable refractive outcomes to nonrebubbled eyes (P >0.05), rebubbled DSAEK eyes had worse refractive outcomes at all time points (P < 0.05). Graft detachments in DSAEK and DMEK are influenced by various factors, including donor tissue characteristics, tissue preparation, and surgical technique. Identifying and understanding these factors can potentially improve postoperative outcomes.

Intraocular Lens Opacification After Descemet's Membrane Endothelial Keratoplasty-Risk Factors and Outcomes After Intraocular Lens Exchange.

To determine risk factors for intraocular lens opacification (IOLop) after Descemet membrane endothelial keratoplasty (DMEK) and to analyze clinical outcomes after IOL exchange. Cross-Sectional Study: Analysis of all cases of IOL exchange because of post-DMEK IOLop with a minimum of 6-month postoperative follow-up observed in clinic between November 2021 and April 2022. Main outcomes analyzed at the study visit were change in logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity after IOL exchange, endothelial cell loss (ECL), and graft survival. An historical cohort of 232 pseudophakic DMEK eyes was retrospectively analyzed to determine risk factors for post-DMEK IOLop. Cross-Sectional Study: Four eyes were observed (median follow-up = 45 (35.5-86.8) months). IOL materials were hydrophilic acrylic IOLs in 2 eyes and hydrophobic-hydrophilic in the other 2. At the study visit, improvement in median best-corrected visual acuity after IOL exchange was statistically significant (0.25 (0.19-0.41) logMAR to 0.00 (0-0.10) logMAR; P = 0.041). ECL ranged between 57.7% and 85.3%, without cases of graft failure. In the historical cohort, 21 eyes (9.05%) had some IOLop. In multivariate logistic regression model (105 eyes where IOL material data was available), IOLs with high water content material (odds ratio = 65.5, P = 0.0005) and rebubbling (odds ratio = 9.51, P = 0.0138) were independent risk factors for post-DMEK IOLop. Post-DMEK IOLop is infrequent, but a non-neglectable proportion of cases may require IOL explantation. IOL exchange is safe and effective in these eyes but may pose a risk for increased ECL. This study confirms that IOL material and number of rebubblings are major risk factors for post-DMEK IOLop.

Comparison of rebubbling rate between preloaded endothelium-in and preloaded no-touch endothelium-out Descemet membrane endothelial keratoplasty transplantation

BackgroundTo compare the difference in rebubbling rates between patients undergoing Descemet membrane endothelial keratoplasty (DMEK) with endothelium-in using a standard IOL cartridge and those with endothelium-out DMEK utilizing a no-touch technique with borosilicate glass cartridge transplantation.MethodsThis retrospective study included all eyes that underwent preloaded endothelium-in or endothelium-out DMEK transplantation from June 2019 to December 2023 at the Hanusch Hospital, Vienna, Austria. All DMEKs were harvested, prepared and preloaded at the European Eye Bank of Venice, Italy. DMEK surgeries were done by one experienced surgeon and the procedure was completed by air tamponade of the anterior chamber.ResultsOverall, 32 eyes each of 31 endothelium-out patients and of 29 endothelium-in patients were included. 32 preloaded endothelium-in procedures were followed by 32 preloaded endothelium-out procedures. Rebubbling rate for endothelium-in was 15/32 (47%) and for endothelium-out was 7/25 (28%) (p = 0.035, Pearson’s chi-squared test). Donor age was the most important variable for rebubbling in a random forest algorithm model (ROC: 0.69).ConclusionsRebubbling rate in endothelium-out DMEK was less than two-thirds compared to endothelium-in DMEK favoring no-touch endothelium-out DMEK as the preferred technique of DMEK transplantation.

Descemet Membrane Endothelial Keratoplasty in Aphakic, Aniridic, and Vitrectomized Eyes: A Review.

The aim of this review is to examine the techniques, complications, and outcomes of Descemet membrane endothelial keratoplasty (DMEK) in aphakic, aniridic, and vitrectomized eyes. A literature search was conducted in the MEDLINE database (via PubMed), using as keywords "(DMEK) AND (aphakia OR aniridia OR vitrectomy OR vitrectomized)." The research was limited to 10 years (January 2014-March 2024), in view of lack of literature before 2014. Articles, including case reports and case series, were included. Twenty articles were included. No randomized controlled trials were found nor comparative studies with more than 1 technique used. Mean rebubbling rate in complex eyes was 29%, whereas mean endothelial cell loss at 6 months was 37%. The mean postoperative visual acuity improved from 1.47 logarithm of the minimal angle of resolution to 0.7 logarithm of the minimal angle of resolution. Despite being more challenging, compared with the techniques reported in literature, DMEK can be considered a valid option for the management of endothelial decompensation in complex eyes, with rebubbling rate and endothelial cell loss at 6 months, which are similar to non-complex eyes.

Outcomes of Donor Corneas of Different Thicknesses From Endothelial Keratoplasty in Deep Anterior Lamellar Keratoplasty for Keratoconus.

To evaluate the outcomes of divided residual donor corneas obtained from endothelial keratoplasty in keratoconus with deep anterior lamellar keratoplasty (DALK). In this retrospective, comparative, clinical study, 103 keratoconic eyes that underwent DALK were enrolled; 67 eyes received thin grafts from Descemet stripping automated endothelial keratoplasty, and 36 received thick grafts from Descemet membrane endothelial keratoplasty. Baseline and postoperative central corneal thickness (CCT), inferior corneal thickness, uncorrected distance visual acuity, corrected distance visual acuity, corneal astigmatism, mean keratometry, biomechanical properties, and complication rates were measured. Six months after transplantation, the group receiving thin grafts had a CCT of only 455.1 ± 43.0 μm, whereas that of the group receiving thick grafts was 546.7 ± 44.2 μm. Both CCT and inferior corneal thickness in the thin group were significantly lower than those in the thick group (measured with Pentacam at 36 months, P < 0.001) and remained throughout the 5-year follow-up period. Both procedures had comparable postoperative logarithm of the minimum angle of resolution UDVAs, logarithm of the minimum angle of resolution corrected distance visual acuity, astigmatism, and mean keratometry values (36 months; P = 0.335, 0.286, 0.680, and 0.365, respectively). Corneal biomechanical analysis revealed that the thin group had a significantly higher stiffness parameter at the first applanation than the thick group at the 2-year follow-up (P = 0.036) while other parameters were equivalent. The outcomes of keratoplasty with donor tissue are comparable regardless of the thickness of the graft, which suggests that transplantation with either type of the split corneal procedure for DALK in patients with keratoconus is feasible.

Clinical Outcomes of Repeat Descemet Membrane Endothelial Keratoplasty After Graft Failure.

To evaluate the clinical outcomes after repeat Descemet membrane endothelial keratoplasty (DMEK) for technical failure (TF) and secondary graft failure (SGF). Retrospective analysis of 49 eyes that underwent repeat DMEK either for TF (ie, persistent graft detachment, n = 24) or for SGF (ie, late endothelial graft failure, n = 25). Surgery indications for primary DMEK were Fuchs endothelial corneal dystrophy (FECD, 80%) and bullous keratopathy (BK, 20%). Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (ECD), corneal backscattering, pachymetry, and graft survival. Outcomes were compared with an age-matched control group of 49 primary DMEK eyes. Logarithm of the minimum angle of resolution BCVA improved from 0.92 ± 0.6 before to 0.20 ± 0.3 at 1 year after repeat DMEK with better outcomes for eyes with TF than those with SGF (P = 0.046). Donor ECD decreased from 2618 ± 171 cells/mm2 before to 1247 ± 422 cells/mm2 at 1 year postoperatively, with no difference between technical TF and SGF eyes (P > 0.05). One-year BCVA and ECD outcomes were better in the control group than in the repeat DMEK group (P < 0.05). Five-year graft survival probability after repeat DMEK was better for TF than for SGF eyes (100% vs. 75%, P = 0.010) and better for eyes with FECD than BK as primary indication for surgery (92% vs. 65%, P = 0.042). Repeat DMEK gives acceptable clinical outcomes especially when performed for TF in the early period after primary DMEK. Long-term graft survival probability after repeat DMEK is comparable to primary DMEK for FECD eyes, whereas BK eyes may show an elevated risk to develop graft failure again.

Impact of the ratio between graft and host corneal size on immune rejection, re-bubbling rate and postoperative endothelial cell loss in 457 eyes after Descemet membrane endothelial keratoplasty (DMEK)

The aim of this study was to assess the impact of the ratio between the graft and host corneal size (RGH) on postoperative complications, such as immune reactions, re-bubbling rate and endothelial cell loss (ECL) after Descemet membrane endothelial keratoplasty (DMEK). Retrospectively, 457 patient eyes were included which had undergone surgery between 2016 and 2019 in the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar using DMEK or triple DMEK, diagnosed as Fuchs' endothelial dystrophy (n = 431), pseudophakic bullous keratopathy (n = 9) and others (n = 17). The follow-up period extended until the end of 2020.Main outcome measures included immune reaction (IR), re-bubbling rate and the postoperative endothelial cell loss (ECL) at 6weeks, 6months and 12months and whether these measures depended on the RGH. The RGH in this study ranged from 0.35 to 0.62 (0.46 ± 0.04). There were 33(7.2%) postoperative IRs (DMEK n = 25; triple DMEK n = 8). The average RGH without IR (0.46 ± 0.04) was significantly (p = 0.038) smaller than in the group with IR (0.47 ± 0.05). Re-bubbling was necessary in 159 of 457 (34.8%) patient eyes. The RGH in patient eyes with re-bubbling (0.47 ± 0.04) was significantly (p = 0.014) higher than that in eyes without re-bubbling (0.45 ± 0.04). The mean preoperative endothelial cell count (ECD) was 2603 ± 251 cells/mm2 (min: 2161, max: 3500 cells/mm2). It was shown that alarger RGH had no positive influence on endothelial cell loss (r = 0.001; p = 0.974). Our results suggest that alarger graft diameter compared to host corneal size is associated with an increased rate of immune reactions and ahigher re-bubbling rate after DMEK. Otherwise, alarger RGH had no positive influence on endothelial cell loss after DMEK. Accordingly, the graft size for DMEK should not be unnecessarily large, especially in eyes with Fuchs' endothelial dystrophy.

Contact Lens-Assisted DMEK for Corneal Decompensation With an Anterior Chamber Intraocular Lens: A Novel Technique.

To describe a novel technique in which a contact lens was used to facilitate Descemet membrane endothelial keratoplasty (DMEK) in an eye with an anterior chamber intraocular lens (ACIOL). A 71-year-old man with a long-standing ACIOL developed bullous keratopathy. As the patient was at high risk of complications due to multiple ocular comorbidities, DMEK was performed with the ACIOL left in the anterior chamber. An inserted cosmetic contact lens was used as a platform for the graft unfolding. Partial graft detachment on the third postoperative day required rebubbling. This successfully cleared up the cornea after a few weeks. At the one-month follow-up, the uncorrected distance visual acuity improved to 20/50, with an endothelial cell loss of 35.2%. Steroid-induced ocular hypertension necessitated a trabeculectomy by the fifth postoperative month. At the sixth follow-up month, endothelial cell loss was 64%. Contact lens-assisted DMEK is a safe procedure for eyes with an ACIOL. However, good foresight is needed regarding whether the ACIOL should be kept or exchanged.

Descemet Membrane Endothelial Keratoplasty for Endothelial Failure in Primary Angle Closure Suspects.

To analyze the feasibility and outcome of Descemet membrane endothelial keratoplasty (DMEK) for treatment of endothelial failure in primary angle closure suspect (PACS) eyes. Retrospective, single-center case series of eyes treated by DMEK for endothelial failure caused by PACS. Main study parameters were success rate of DMEK, best-corrected visual acuity, anterior chamber depth, central corneal thickness, and endothelial cell density. Mean follow-up time was 16 ± 13 months. Ten eyes of 9 patients receiving DMEK for the treatment of corneal endothelial failure because of PACS were included. Except for 2 eyes that had undergone cataract surgery, none of the eyes had previous ocular surgery. DMEK combined with cataract surgery was performed in 5 eyes, DMEK alone with second-step cataract surgery in 2 eyes. The eyes with corneal edema after cataract surgery received DMEK only. DMEK surgery was successful in nine out of 10 eyes, 1 patient required repeat DMEK because of primary graft failure. In the group of phakic eyes, mean preoperative internal anterior chamber depth was 1.74 ± 0.18 mm. In eyes with corneal edema, central corneal thickness was 849 ± 205 μm before DMEK surgery, and 517 ± 24 μm at the final postoperative visit (P = 0.002). DMEK is a feasible option in eyes with endothelial failure because of primary angle closure. In case of advanced corneal edema, a second-step procedure (first DMEK, second cataract surgery) is a possible approach if visibility of the lens is too poor for simultaneous cataract surgery.

Predicting Success in Descemet Membrane Endothelial Keratoplasty Surgery Using Machine Learning.

This study aimed to predict early graft failure (GF) in patients who underwent Descemet membrane endothelial keratoplasty based on donor characteristics. Several machine learning methods were trained to predict GF automatically. To predict GF, the following variables were obtained: donor age, sex, systemic diseases, medications, duration of stay in the intensive care unit, death-to-preservation time (DPT), endothelial cell density of the cornea, tightness of Descemet membrane roll during surgery, anterior chamber tamponade, tamponade used for rebubbling, and preoperative best corrected visual acuity. Five classification methods were experimented with the study data set: random forest, support vector machine, k-nearest neighbor, RUSBoosted tree, and neural networks. In holdout validation, 75% of the data were used in training and the remaining 25% used in testing. The predictive accuracy, sensitivity, specificity, f-score, and area under the receiver operating characteristic curve of the methods were evaluated. The highest classification accuracy achieved during the experiments was 96%. The precision, recall, and f1-score values were 0.95, 0.81, and 0.90, respectively. Feature importance was also computed using analysis of variance. The model revealed that GF risk was related to DPT and the intensive care unit duration (P < 0.05). No significant relationship was found between donor age, endothelial cell density, systemic diseases and medications, graft roll, tamponades, and GF risk. This study shows a strong relationship between increased intensive care duration, DPT, and GF. Experimental results demonstrate that machine learning methods may effectively predict GF automatically.

A Functional and Immunologic Point of View on Corneal Endothelial Transplantation: A Systematic Review and Meta-Analysis.

Background: To systematically review and meta-analyze the immunologic aspects and outcomes of various endothelial keratoplasty (EK) techniques, specifically comparing Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), Ultra-Thin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK), and Descemet's Membrane Endothelial Keratoplasty (DMEK). Methods: Systematic review and meta-analysis. Main outcomes were the proportion of patients achieving a best spectacle-corrected visual acuity (BSCVA) of 20/20 at 6 months after keratoplasty, rejection rate one year after surgery, BSCVA at last follow up, and postoperative immunomodulating regimen. Results: A higher proportion of DMEK patients achieved a BSCVA of 20/20 after 6 months. UT-DSAEK and DMEK showed similar rejection rates with a lower risk of re-bubbling for UT-DSAEK (4% vs. 20%). Conclusions: DMEK showed faster visual recovery than UT-DSAEK but a similar rejection rate and long-term visual acuity. One-year postoperative slow tapering steroid regimen has a positive but not (yet) significant effect on rejection risk and visual outcomes.

DMEK Surgery at a Tertiary Hospital in Sweden. Results and Complication Risks.

This study reports clinical outcomes up to 6 years after Descemet's membrane endothelial keratoplasty (DMEK) performed at the Department of Ophthalmology, Örebro University Hospital, Örebro, Sweden. The study has a cross-sectional and case series design. Inclusion criteria were all DMEK-operated eyes during 2013-2018 until repeat keratoplasty. Altogether 162 eyes from 120 patients were enrolled. Among eyes without preoperative comorbidities, examined 1-6 years after DMEK, 85.8% achieved visual acuity of 0.1 logMAR or better. The median endothelial cell density (ECD) loss was 27% in a cohort of eyes examined 1-2 years post-DMEK, 31% at 2-3 years, 42% at 3-4 years, and > 60% at 4-6 years post-DMEK. ECD at the examination timepoint was correlated with donor ECD (as expected) and time since surgery. The results from DMEK surgeries in Örebro, Sweden, are promising. Further studies with even longer follow-up are needed to evaluate graft sustainability.

An Enigmatic Fluid Accumulation Following Descemet Membrane Endothelial Keratoplasty After Prior Laser In Situ Keratomileusis

Purpose: To report a case of interface fluid syndrome (IFS) following Descemet membrane endothelial keratoplasty (DMEK) 13 years after laser in situ keratomileusis (LASIK). Methods: A 79-year-old patient with bullous keratopathy underwent uneventful DMEK. Thirteen years prior, he had undergone LASIK. After DMEK, he developed an IFS, which was confirmed by a fluid accumulation in the flap interface, visible in the anterior segment optical coherence tomography (AS-OCT). In this case, IFS is presumed to have been triggered by the corticosteroid eye drops administered postoperatively. Measurements of the intraocular pressure (IOP) via applanation tonometry yielded erroneously low results. Results: The discontinuation of the corticosteroid eye drops, along with the initiation of IOP-lowering therapy, led to an improvement in fluid accumulation and a decrease in IOP. Regular ophthalmic examinations with a palpatory assessment of IOP and monitoring of fluid via AS-OCT are recommended. In this case, no more fluid could be detected in the flap interface after 14 months, and IOP was normal. Conclusions: IFS can occur many years after LASIK treatment. Corticosteroids should be discontinued, and IOP-lowering therapy should be initiated to prevent irreversible damage to the optic nerve. Applanation tonometry leads to inaccurately low IOP measurements; therefore, a palpatory assessment of IOP is recommended. AS-OCT is a crucial imaging modality that should be employed for monitoring.

Principal Component Analysis of a Real-World Cohort of Descemet Stripping Automated Endothelial Keratoplasty and Descemet Membrane Endothelial Keratoplasty Cases: Demonstration of a Powerful Data-Mining Technique for Identifying Areas of Research.

Principal component analysis (PCA) is a descriptive exploratory statistical technique that is widely used in complex fields for data mining. However, it is rarely used in ophthalmology. We explored its research potential with a large series of eyes that underwent 3 keratoplasty techniques: Descemet membrane endothelial keratoplasty (DMEK), conventional Descemet stripping automated endothelial keratoplasty (ConDSAEK), or ultrathin-DSAEK (UT-DSAEK). All consecutive DMEK/DSAEK cases conducted in 2016 to 2022 that had ≥24 months of follow-up were included. ConDSAEK and UT-DSAEK were defined as preoperative central graft thickness ≥130 and <130 μm, respectively. Seventy-six patient, disease, surgical practice, and temporal outcome variables were subjected to PCA, including preoperative anterior keratometry, the use of sulfur hexafluoride gas (SF6) versus air for primary tamponade, and postoperative best corrected visual acuity and endothelial cell density. Associations of interest that were revealed by PCA were assessed with the Welch t test or Pearson test. A total of 331 eyes were treated with DMEK (n = 165), ConDSAEK (n = 95), or UT-DSAEK (n = 71). PCA showed that ConDSAEK and UT-DSAEK clustered closely, including regarding postoperative best corrected visual acuity, and were clearly distinct from DMEK. PCA and follow-up univariate analyses suggested that in DMEK, 1) flatter preoperative anterior keratometry (average, K1, and K2) associated with more rebubbling (P = 0.004-0.089) and graft detachment (P = 0.007-0.022); 2) graft marking did not affect postoperative ECD; and 3) lower postoperative endothelial cell density associated with SF6 use (all P > 0.001) and longer surgery (P = 0.005-0.091). All associations are currently under additional investigation in our hospital. PCA is a powerful technique that can rapidly reveal clinically relevant associations in complex ophthalmological datasets.

Corneal Backscatter, Pachymetric Indices, and Ectasia Indices for the Assessment of Fuchs Endothelial Corneal Dystrophy.

To determine whether corneal backscatter, pachymetric indices, and ectasia indices derived from Scheimpflug tomography can identify Fuchs endothelial corneal dystrophy (FECD) corneas with abnormal tomography, the relationships between these parameters and tomographic edema in FECD, and if these parameters help predict improvement in central corneal thickness (CCT) after Descemet membrane endothelial keratoplasty (DMEK). Tomography maps of 132 eyes of 80 subjects with FECD were analyzed to determine how backscatter, pachymetric, and ectasia parameters compared with the instrument's normative database and if any predicted tomographic edema. Tomography maps from a separate group undergoing DMEK were split into derivation (48 eyes of 39 subjects) and validation (45 eyes of 41 subjects) subgroups to derive a predictive model of improvement in CCT after DMEK. Backscatter, pachymetric, and ectasia parameters were incorporated to determine if the model could be enhanced. Among all ectasia, pachymetric, and backscatter parameters, at best only 65% of FECD corneas with definite tomographic edema could be identified based on the instrument's normative database. Among all parameters individually, the highest sensitivity for detecting tomographic edema was 77%. Anterior and mid-corneal backscatter featured in a model predicting improvement in CCT after DMEK with high performance in derivation (R2 = 0.79; 95% confidence interval, 0.65-0.87) and validation (R2 = 0.72; 95% confidence interval, 0.52-0.83) subgroups. The Scheimpflug camera software program could not reliably detect abnormal tomography in FECD from corneal backscatter, pachymetric indices, or ectasia indices. Corneal backscatter contributes to, but does not enhance, a predictive model of improvement in CCT after DMEK.

Keratoplasty - an Overview of the Methods and their Perioperative Management

Corneal transplantation can be divided into two groups: penetrating and lamellar keratoplasty. Newer minimally invasive procedures have emerged over the years, to improve the visual outcome and reduce complications. This article summarizes the different procedures, their indications and complications, and outlines the pre-, peri- and postoperative management in a clinical setting.Corneal transplantation is the most commonly performed transplantation of donor tissue in modern medicine. In the last years a shift away from penetrating keratoplasty (PK) towards minimally invasive lamellar operative techniques, associated with less complications, can be observed. The Descemet membrane endothelial keratoplasty (DMEK) is used to treat endothelial corneal pathologies and has overtaken the PK to become the most commonly performed form of keratoplasty. Preparation and identification of possible risk-factors are essential preoperative steps to reduce peri- and postoperative complications of keratoplasties. If corneal graft rejection occurs, early and maximum therapy is crucial for graft survival. Laser-assisted techniques offer different advantages in lamellar and penetrating keratoplasty but are not very cost-efficient.