Transplantation Of Descemet Membrane Research Articles

Comparative Analysis of Clinical and Functional Results of Standard and Modified Endothelial and Descemet Membrane Transplantation Techniques

Purpose: to evaluate the clinical and functional results of two methods of Descemet’s membrane endothelial keratoplasty using a full and half graft.Patients and methods. This study is based on surgical treatment of 54 patients (54 eyes) with cataracts and Fuchs endothelial corneal dystrophy were divided into two groups. In the first one, phacoemulsification of cataract with implantation of a hydrophobic IOL and standard «classical» technique of Descemet’s membrane endothelial keratoplasty were performed, it included 30 patients (30 eyes). The second group underwent cataract phacoemulsification with implantation of a hydrophobic IOL and modified transplantation of a fragment (1/2) of Descemet’s membrane, it included 24 patients (24 eyes).Results. Transparent engraftment in the first group was achieved in 100 % of cases (30 out of 30 patients), in the second group in 95.8 % of cases (23 out of 24 patients). It should be noted that in the second group, one patient had fibrosis of the posterior layers of the corneal stroma (due to incomplete adherence of the DM to the posterior surface of the recipient’s cornea), this complication required endothelial re-keratoplasty. After 12 months, the BCVA improved from 0.2 ± 0.1 to 0.8 ± 0.2 in the first group, from 0.1 ± 0.1 to 0.7 ± 0.2 in the second group (p < 0 ,0001). The central corneal thickness (CCT) according to keratopachymetry in the first group decreased from 648.7 ± 60 to 512.4 ± 27.4 μm, in the second group — from 650.9 ± 44.5 to 519.6 ± 43.9 μm respectively. The endothelial cell loss (ECL) was 52.3 % and 54.9 % in the first and second groups respectively.Conclusion. The modified technique of Descemet’s membrane endothelial keratoplasty is effective for the treatment of Fuchs’ endothelial corneal dystrophy providing high clinical and functional results. A comparative analysis of the results obtained showed that at all results of BCVA, ECC and CCT by 12 months after surgery were comparable between two groups. Thus, the use of the new technique made it possible to double the availability of donor material and provide patients good clinical outcomes comparable to those of «classical» DMEK.

Ultraviolet crosslinking of corneal collagen in patients with thin cornea. Literature review

For the treatment of progressive keratoconus in the early stages, corneal collagen crosslinking is currently actively used. This technique is based on the stabilization of the pathological process by increasing the biomechanical properties of the own cornea. The thickness of the cornea less than 400 microns significantly limits the possibility of a standard cross-linking procedure performing.The article analyzes the literature data on the use of various methods of corneal crosslinking with a corneal thickness of less than 400 microns, which signifi cantly limits the possibilities of the standard procedure.It is known, that during crosslinking, at the initial stage, de-epithelialization of the cornea is performed, which, in the postoperative period, leads to a pronounced corneal syndrome. This determined the direction of the fi rst modifi cations of the technique associated with the use of partial de-epithelialization or its complete absence. Later, during cross-linking of “thin” corneas, techniques with the use of additional covering materials were actively used in order to replenish the missing corneal tissue of the patient during the UV irradiation procedure. Among them are the use of a soft contact lens without an ultraviolet fi lter, the use of a corneal lenticule obtained after SMILE surgery, the use of a protective fl ap of the donor cornea obtained using a femtosecond laser from the residual stroma of the corneal disc after descemet membrane transplantation or posterior lamellar keratoplasty. The variety of the proposed modifications and the ongoing search for better options indicate the demand for this technology and the need for further research, taking into account the individual characteristics of the patient’s ectasia.

New Therapies for Corneal Endothelial Diseases: 2020 and Beyond.

Penetrating keratoplasty used to be the only surgical technique for the treatment of end-stage corneal endothelial diseases. Improvements in surgical techniques over the past decade have now firmly established endothelial keratoplasty as a safe and effective modality for the treatment of corneal endothelial diseases. However, there is a worldwide shortage of corneal tissue, with more than 50% of the world having no access to cadaveric tissue. Cell injection therapy and tissue-engineered endothelial keratoplasty may potentially offer comparable results as endothelial keratoplasty while maximizing the use of cadaveric donor corneal tissue. Descemet stripping only, Descemet membrane transplantation, and selective endothelial removal are novel therapeutic modalities that take this a step further by relying on endogenous corneal endothelial cell regeneration, instead of allogenic corneal endothelial cell transfer. Gene therapy modalities, including antisense oligonucleotides and clustered regularly interspaced short palindromic repeats-based gene editing, offer the holy grail of potentially suppressing the phenotypic expression of genetically determined corneal endothelial diseases at the asymptomatic stage. We now stand at the crossroads of exciting developments in medical technologies that will likely revolutionize the way we treat corneal endothelial diseases over the next 2 decades.

Optical reconstructive surgery of the anterior segment of the eye in the far eastern federal district – achievements and unsolved problems

The aim was to analyze organizational and technical difficulties in introducing modern technologies of optical reconstructive surgery, and to find the options of their elimination.
 Materials and methods. Organizational arrangements to develop and to introduce into clinical practice modern technologies of optical reconstructive surgery in treatment of corneal opacities of different origin in the Khabarovsk branch of the S. Fedorov Eye Microsurgery Federal State Institution of the Ministry of Health of the Russian Federation has been analyzed.
 Results and conclusions. An unified register of patients of the Far Eastern Federal district who need optical keratoplasty (bullous keratopathies, keratoconus stages 34, post-traumatic leukomas, hereditary corneal dystrophies) a waiting list has been created. The necessary equipment and instruments were acquired, 4 surgeons were trained who mastered the technologies of deep anterior lamellar keratoplasty and Descemet membrane transplantation along with penetrating keratoplasty. From 2014 to 2018, 160 optical keratoplasty were performed using donor material; by 2019, the need for this type of high-tech treatment has been reduced by 2 times. To date, more than 30% of optical keratoplasties are performed using lamellar technology. The organizational sequence of ordering biological material, performing surgeries; the postoperative care system is got up and running; the outpatient departmentsophthalmologists of the region are trained to use clear objective criteria for dynamic follow-up of these patients.

Intrastromal Descemet Membrane Transplantation as a Potential Alternative to Bowman Layer Inlays in Eyes With Advanced Keratoconus.

Herein, we report the outcomes of intrastromal Descemet membrane (DM) transplantation in corneas with advanced keratoconus. Three eyes (three patients) showed advanced keratoconus. No eye underwent prior UV-cross-linking or any other ocular surgery. In all eyes, A donor DM was implanted into a mid-stromal pocket and clinical outcomes were evaluated up to 24 months after surgery. All procedures were uneventful. Up to 24 months postoperatively, the DM graft was well-positioned and barely visible within the recipient stroma; all corneas were clear. No eye showed signs of keratoconus progression throughout the follow-up. No changes were observed in uncorrected and best contact lens corrected visual acuity, central endothelial cell density, corneal thinnest point pachymetry, and maximum keratometry values. No early or late postoperative complications were observed. Intrastromal DM transplantation may be an alternative to intrastromal Bowman layer transplantation in advanced keratoconus, to postpone deep anterior lamellar or penetrating keratoplasty.

Intrastromal descemet membrane transplantation in eyes with advanced keratoconus

Background. To report the outcomes of intrastromal Descemet membrane (DM) transplantation in corneas with advanced keratoconus.
 Materials and methods. Three eyes of 3 patients presented with advanced, progressive keratoconus. None of the eyes had prior UV-crosslinking or any other ocular surgery performed. All eyes had a donor DM implanted into a mid-stromal pocket under local anesthesia, and clinical outcomes were evaluated at 12 months after surgery.
 Results. To the best of our knowledge, this is the first report of DM transplantation performed in cases of advanced keratoconus. At 12 months after surgery, the DM graft was well positioned and barely visible within the recipient stroma, and all corneas were clear. None of the eyes showed signs of keratoconus progression throughout the follow-up period. No significant changes were observed in uncorrected (UCVA) and best contact lens corrected visual acuity (BCLCVA), central endothelial cell density (ECD), corneal thinnest point (CTP) pachymetry, and maximum keratometry values (SimK and Kmax). No early or late postoperative complications were observed.
 Conclusions. Intrastromal DM transplantation may potentially be an alternative to intrastromal Bowman layer transplantation in eyes with advanced keratoconus, to postpone deep anterior lamellar or penetrating keratoplasty.

Automated Clinical Assessment of Corneal Guttae in Fuchs Endothelial Corneal Dystrophy

To describe the validation and implementation of an automated system for the detection and quantification of guttae in Fuchs endothelial corneal dystrophy (FECD). Observational reliability study. Patients with FECD underwent retroillumination corneal photography, followed by determination of the distributions and sizes of corneal guttae by an automated image analysis algorithm. Performance of the automated system was assessed via (1) validation against manual guttae segmentation, (2) reproducibility studies to ensure consistency, and (3) evaluation for agreement with the Krachmer scale. It was then deployed to perform large-scale guttae assessment with anatomic subregion analysis in a batch of 40 eyes. Compared to manual segmentation, the automated system was reasonably accurate in identifying the correct number of guttae (mean count of 78 guttae per 1× 1mm test frame, overestimation:+10 per frame), but had a tendency to significantly overestimate guttae size (mean guttae size 1073μm2, overestimation:+255μm2). Automated measurements of guttae counts and sizes were reproducible within a 1% discrepancy range across repeat intra-eye assessments. Automated guttae counts, interguttae distances, and density of interguttae gaps lesser than 40μm (ie, D40 density) were highly correlated with the Krachmer scale (P < .001 for all). Large-scale guttae assessment demonstrated the automated system's potential to selectively identify a region of the corneal endothelium most affected by densely packed guttae. Automated guttae assessment facilitates the precise identification and quantification of guttae characteristics in FECD patients. This can be used clinically as a personalized descemetorrhexis zone for Descemet stripping only and/or Descemet membrane transplantation.

Regenerative medicine in Fuchs' endothelial corneal dystrophy.

The management of Fuchs' endothelial corneal dystrophy (FECD) has evolved rapidly since the introduction of endothelial keratoplasty (EK). In recent years, advances in our understanding of endothelial cell biology, in particular with respect to the regenerative capacity of endothelial cells, have opened the door to novel therapeutic options that stray from the traditional paradigm of allograft transplantation. We review the development of descemetorhexis without EK (DWEK) as a primary treatment for FECD and discuss the lessons learned to date about the mechanism of wound healing, surgical technique, patient selection, and refractive outcomes. Multiple randomized clinical trials are currently underway to evaluate the potential for pharmacological supplementation with rho-associated kinase inhibitors to increase the success rate of corneal clearance following DWEK. Biologic supplementation with intracameral endothelial cell injection and acellular Descemet's membrane transplantation are other avenues of adjuvant therapy. DWEK is a promising surgical option for management of a subset of FECD patients.

THE ORGANIZATION OF OPTICAL KERATOPLASTY IN THE REHABILITATION OF PATIENTS WITH ANOMALIES AND CORNEAL OPACITIES

The article analyzes the organization and clinical efficacy of keratoplasty for visual purpose, conducted in the Khabarovsk branch of the FSAI NMRC ISTC «Eye Microsurgery named after academician S.N. Fedorov» of the Russian Federation. 111 patients (111 eyes) were operated on for: bullosa keratopathy 3-4 degrees - 55 eyes; stage 4 keratoconus - 37 eyes; posttraumatic cornea belmas of 3-4 categories - 14 eyes; hereditary corneal degeneration - 5 eyes. In 88 eyes, the technique of penetrating keratoplasty was applied, in 19 eyes - anterior deep layered keratoplasty, in 4 eyes - descemet membrane transplantation.

Evolving Therapies for Fuchs Endothelial Dystrophy

Fuchs endothelial corneal dystrophy (FED) is one of the leading indications for corneal transplantation. Over the last two decades we have seen a significant shift in transplantation procedures for endothelial disease away from penetrating keratoplasty to small incision procedures such as Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty. More recently, even newer concepts have come to light to explore options of regenerative therapy for FED, e.g. Descemet stripping without endothelial keratoplasty, Descemet membrane transplantation and the use of adjuncts such as Rho kinase inhibitors. Furthermore, alternative strategies involving tissue engineering approaches with the use of cell therapy are also reaching early clinical trial stage. With more information on the underlying genetic abnormalities in FED, gene therapy may be a possible future treatment.

Allogeneic Descemet's Membrane Transplantation Enhances Corneal Endothelial Monolayer Formation and Restores Functional Integrity Following Descemet's Stripping.

To characterize the differences in corneal endothelial wound healing in the presence or absence of Descemet's membrane (DM), in vivo. New-Zealand white rabbits were subjected to 7-mm endothelial wound either by scraping (n = 8; DM intact), peeling (n = 6; DM removed), or a combinatory scrape/peel wound (n = 6). In a second experiment, rabbits underwent peel wound with immediate transplantation of pure decellularized human DM (n = 4). In vivo endothelial migration was assessed via trypan blue staining. Recovery of corneal clarity and thickness was performed by using slit-lamp biomicroscopy and optical coherence tomography. Cell proliferation, phenotype, and morphology were assessed by using immunofluorescence and scanning electron microscopy. In vivo wound closure was faster in the presence of DM; 25.4% ± 1.4%/d versus 5.5% ± 0.6%/d (P < 0.0001). At day 8, complete wound closure was seen in all of the scrape samples but none of the peel group, with wound closure preceding clinical recovery by approximately 6 days in the scrape group. Endothelial cells in the scraped areas reformed functional monolayers capable of restoring corneal thickness and transparency whilst those in the peeled area underwent mesenchymal-like transformation resulting in scar formation. Transplanting decellularized DM in animals receiving a peel wound resulted in clarity and thickness comparable to the scrape group. Endothelial proliferation (Ki67 +ve cells) was higher in scraped versus peeled areas: 54.7% ± 3.5% vs. 8.8% ± 0.7%, (P < 0.01). The presence of DM promoted endothelial wound healing, proliferation, and maintenance of a normal phenotype. DM transplantation recovered the abnormal peel phenotype back to that observed after endothelial scraping.

Outcomes of Descemet membrane endothelial keratoplasty in phakic eyes

To determine the clinical outcomes of isolated Descemet membrane transplantation (ie,Descemet membrane endothelial keratoplasty [DMEK]) in phakic eyes. Tertiary referral center. Cohort study. Phakic eyes from a larger group of consecutive eyes that had DMEK for Fuchs endothelial dystrophy were examined. The examination included corrected distance visual acuity (CDVA), subjective and objective refractions, endothelial cell density (ECD), and intraoperative and postoperative complications at 1, 3, and 6 months. The study enrolled 52 phakic eyes from a group of 260 DMEK eyes. Of the phakic eyes,69% reached a CDVA equal to or better than 20/40 (≥0.5) within 1 week and 85% reached equal to or better than 20/25 (≥0.8) at 6 months. Compared with an age-matched control group of pseudophakic eyes, phakic eyes had a similar visual rehabilitation rate, final visual outcome, mean ECD at 6months (1660 cells/mm(2) ± 470 [SD]), minor hyperopic shift (+0.74 diopter), and graft detachment rate (4%). Visual acuity equal to or better than 20/13 (≥1.5) was limited to phakic eyes, suggesting better optical quality with the crystalline lens in situ. Temporary mechanical angle-closure glaucoma due to air-bubble dislocation behind the iris was the main complication (11.5%). Two eyes (4%) required phacoemulsification after DMEK. In phakic eyes, DMEK may give excellent visual outcomes without an increased risk for complications. Visual acuities equal to or better than 20/13 (≥1.5) may indicate that the almost anatomic repair after DMEK is associated with near perfect optical quality of the transplanted cornea. Dr. Melles is a consultant to D.O.R.C. International/Dutch Ophthalmic USA. No author has a financial or proprietary interest in any material or method mentioned.

Transplantation of Endothelium and Descemet Membrane for Aphakic Corneal Edema in 1980

To describe a corneal endothelial layer and Descemet membrane transplantation into the anterior chamber for the treatment of bullous keratopathy in 1980. A retrospective report of an intervention case study is presented. A patient with aphakic bullous keratopathy in one eye was interested in undergoing a previously untested corneal transplantation procedure. Snellen visual acuity testing and slit-lamp examination were performed. The main outcome measures were visual acuity and degree of corneal clarity. Visual acuity and corneal clarity improved in the months following the endothelial/Descemet membrane transplant but gradually returned to preoperative levels 1 year later. A subsequent successful penetrating keratoplasty resulted in excellent visual acuity (-20/25). An attempt to perform endothelial and Descemet membrane transplantation for aphakic corneal edema in 1980 resulted in early improvement in corneal clarity and visual acuity but required full penetrating keratoplasty at 2 years postoperatively. [J Refract Surg. 2010;26(7):525-528.] doi:10.3928/1081597X-20090910-01

Endothelial keratoplasty: DSEK/DSAEK or DMEK - the thinner the better?

Endothelial keratoplasty has been adopted worldwide as an alternative to penetrating keratoplasty in the treatment of corneal endothelial disorders. Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) may be the current standard, whereas Descemet membrane endothelial keratoplasty (DMEK), that is, isolated transplantation of Descemet membrane, may allow further improvement of clinical outcome. DSEK/DSAEK may still have three major challenges: suboptimal visual acuity and relatively slow visual rehabilitation, limited accessibility due to required investments in equipment or the purchase of predissected tissue, and a drop in donor endothelial cell density in the early postoperative phase. Although DMEK may allow much quicker and (near) complete visual rehabilitation as well as easier logistics in donor preparation, the surgical technique may initially require more training to obtain consistent outcomes. Compared with DSEK/DSAEK, DMEK may have higher clinical potential with 75% of cases reaching 20/25 or better (> or =0.8) within 1-3 months. Furthermore, preparation of isolated Descemet grafts does not require large investments and may increase overall donor tissue availability. Hence, corneal surgeons may consider 'to make the switch' from DSEK/DSAEK to DMEK.

Visual Rehabilitation Rate After Isolated Descemet Membrane Transplantation

To evaluate visual rehabilitation after Descemet membrane endothelial keratoplasty (DMEK) in the management of corneal endothelial disorders. In this prospective, nonrandomized, clinical study, DMEK was performed in a first group of 35 consecutive patients with either Fuchs endothelial dystrophy or bullous keratopathy. The Descemet membrane was stripped from the recipient posterior stroma with the anterior chamber completely filled with air. Using a 3.0-mm clear corneal incision, an organ-cultured donor Descemet roll 9 to 10 mm in diameter was inserted into the recipient anterior chamber, positioned on the posterior stroma, and secured by completely filling the anterior chamber with air for 45 to 60 minutes. Ten eyes had preexisting ocular disease or an early graft detachment. In the remaining 25 DMEK-treated eyes, best-corrected visual acuity was 20/40 (Snellen notation, 0.5) or more in 18 eyes (72%) within 1 month. At 3 months, best-corrected visual acuity was 20/40 (0.5) or more in 23 of 25 eyes (92%) and 20/25 (0.8) or more in 15 of 25 eyes (60%). In most cases, DMEK results in functional visual rehabilitation within 1 to 3 months. Overall, visual recovery after DMEK may be faster and more complete than with other techniques for (lamellar) keratoplasty for treatment of corneal endothelial disorders. clinicaltrials.gov Identifier: NCT00521898.