Determination of progressive endothelial cell loss after posterior chamber phakic intraocular lens implantation.

Comments about endothelial cell loss after posterior chamber phakic intraocular lens are provided, with a particular emphasis on the importance of determining progressive postoperative cell density reduction, excluding that related to surgical trauma.

Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research.

PURPOSE: Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL. METHODS: PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature. RESULTS: Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL. CONCLUSIONS: Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Plastic vs. glass: the effect of the synthetic material in contact with DMEK tissue during staining on endothelial cell loss.

PURPOSE: Endothelial cell loss (ECL) during Descemet membrane endothelial keratoplasty (DMEK) graft preparation has been shown to affect graft survival and the need for re-grafting. The purpose of this study was to quantitatively assess the impact of the plastic and glass mediums in contact with DMEK donor tissue during intra-operative graft staining on ECL. METHODS: Retrospective study that included patients who underwent DMEK surgery between January 2019 and June 2021 at Hôpital Maisonneuve-Rosemont and the Jewish General Hospital in Montreal, Canada. DMEK grafts were stained with 0.06% Trypan blue ophthalmic solution (VisionBlue®, Dutch Ophthalmic, USA, Exeter, NH) for 120 s in either a plastic or glass medium prior to delivery into the recipient's eye. The ECL was compared between the two groups 12-30 months post-operatively. RESULTS: ECL at 12-30 months was significantly less in the eyes that had received grafts stained in a plastic medium compared to those stained in a glass medium. Graft survival and re-bubbling was higher in the glass group however this difference was not statistically significant. CONCLUSION: Staining of the DMEK graft in a plastic medium caused less ECL compared to the glass medium.

Corneal endothelial cell loss and intraocular pressure following phacoemulsification using a new viscous-cohesive ophthalmic viscosurgical device.

PURPOSE: To compare results of two ophthalmic viscosurgical devices (OVDs)-Viscoat (a dispersive OVD, Alcon) and FR-Pro (a viscous-cohesive OVD, Rayner), in phacoemulsification surgery. METHODS: A prospective randomized controlled study. Patients undergoing phacoemulsification were randomly assigned to receive one of the two OVDs. Exclusion criteria were age under 40, preoperative endothelial cell count (ECC) below 1,500 cells/mm2 and an eventful surgery. The primary outcome was change in ECC from baseline to postoperative month one and month three. Secondary outcomes were the difference between ECC at postoperative month one and month three, changes in IOP and occurrence of an IOP spike ≥ 30 mmHg after surgery. RESULTS: The study included 84 eyes-43 in the Viscoat group and 41 in the FR-Pro group. Mean cell density loss at month one and month three was 17.0 and 19.2%, respectively, for the Viscoat group and 18.4 and 18.8%, respectively, for the FR-Pro group, with no statistically significant difference between the groups (p = 0.772 and p = 0.671, respectively). The mean ECC difference between the month one and month three visits was 50.5 cells/mm2 and was not statistically significant (p = 0.285). One eye in each group had an IOP spike ≥ 30 mmHg, both normalized by postoperative week one. CONCLUSIONS: Viscoat and FR-Pro have comparable results following phacoemulsification surgery, suggesting that while FR-Pro is not a dispersive OVD, its endothelial cell protection may be comparable to one, perhaps due to the addition of sorbitol. Furthermore, a one-month follow-up of ECC seems sufficient in such trials.

Corneal endothelial cell loss after EX-PRESS surgery depends on site of insertion, cornea or trabecular meshwork.

PURPOSE: Previously, we reported that the Ex-press® shunt (EXP) was associated with more rapid reduction in corneal endothelial cells when inserted into the cornea rather than the trabecular meshwork (TM). We compared the reduction rate of corneal endothelial cells between the corneal insertion group and TM insertion group. METHODS: This was a retrospective study. We included patients who had undergone EXP surgery and were followed for > 5 years. We analyzed the corneal endothelial cell density (ECD) before and after EXP implantation. RESULTS: We included 25 patients in the corneal insertion group and 53 patients in the TM insertion group. One patient in the corneal insertion group developed bullous keratopathy. The ECD decreased significantly more rapidly in the corneal insertion group (p < 0.0001), in whom the mean ECD decreased from 2227 ± 443 to 1415 ± 573 cells/mm2 at 5 years with a mean 5-year survival rate of 64.9 ± 21.9%. By contrast, in the TM insertion group, the mean ECD decreased from 2356 ± 364 to 2124 ± 579 cells/mm2 at 5 years, and the mean 5-year survival rate was 89.3 ± 18.0%. The decrease rate of ECD was calculated as 8.3%/year in the corneal insertion group and 2.2%/year in the TM insertion group. CONCLUSIONS: Insertion into cornea is a risk factor for rapid ECD loss. The EXP should be inserted into the TM to preserve the corneal endothelial cells.

Different patterns in the corneal endothelial cell loss after pars plana and pars limbal insertion of the Baerveldt glaucoma implant.

PURPOSE: To assess corneal endothelial cell (CE) loss after pars plana (PP) and pars limbal (PL) insertion of a Baerveldt glaucoma implant (BGI). DESIGN: Retrospective multicenter interventional comparative study. METHODS: We studied central CE loss for 5 years after BGI surgery in 192 eyes. RESULTS: The prevalence of bullous keratopathy (BK) was greater in the PL cohort than in the PP cohort (P = .003). The CE loss after simultaneous PP vitrectomy and tube insertion into the vitreous cavity was 11.9% in the first year, which was greater than that of 2.9% in eyes where the tube was inserted simply into the vitreous cavity after a prior vitrectomy (P = .046). The annual percentage CE loss after the first year decreased unidirectionally in both of those groups and was 1.3% and 1.0% in the fifth year, respectively (P < .001). For limbal insertion, the CE loss in the simple PL cohort was biphasic, decreasing from 10.5% in the first year to 7.0% in the fifth year. Simultaneous cataract and BGI surgery enhanced the CE loss slightly in the first year in the PP and PL cohorts to 13.0% and 14.0%, respectively. However, these increases were not significant (P = .816 and .358, respectively). Low preoperative CE density (P < .001) and insertion site (P = .020) were significant risk factors for the development of BK. CONCLUSIONS: CE loss in the PL and PP cohorts was biphasic and unidirectional, respectively. The difference in annual CE loss became evident over time. PP tube implantation may be advantageous when the preoperative CE density is low.

Effect of guided Ahmed glaucoma valve implantation on corneal endothelial cells: A 2-year comparative study.

PURPOSE: To compare the effects of guided and non-guided Ahmed glaucoma valve (AGV) implantation on the corneal endothelium. METHODS: Medical records of patients who underwent AGV implantation in the anterior chamber (AC) were reviewed retrospectively. The eyes were divided into two groups depending on the use of a guidance technique with spatula and a 4-0 nylon intraluminal stent. Specular microscopy was performed to measure corneal endothelial cell density (ECD) loss after surgery, and the rate of ECD change was calculated. Tube parameters were measured using anterior segment optical coherence tomography (AS-OCT). RESULTS: The ECD loss during 2 years of follow-up was significantly lower in the guided AGV implantation (gAGV) group than in the non-guided implantation (ngAGV) group, and the rate of ECD change was -0.62 ± 1.23 and -1.42 ± 1.57%/month in the gAGV and ngAGV groups, respectively (p = 0.003). The mean tube-cornea distance (TCD) and mean tube-cornea angle (TCA) were significantly greater in the gAGV group than in the ngAGV group. The frequency of tube repositioning within 2 years after surgery was 0% in the gAGV group and 12.66% in the ngAGV group (p = 0.005). CONCLUSIONS: The use of a guidance technique can reduce corneal endothelial loss during the first 2 years after AGV implantation in the AC. The tube was positioned at a more distant and wider angle from the cornea in the eyes of the gAGV group, which may have contributed to the reduced need for tube repositioning to prevent corneal decompensation.

Effect of Head Trauma-Related Deaths on Corneal Endothelial Cell Loss in Eye Bank Donors.

PURPOSE: The purpose of this study was to examine the effect of head trauma-related deaths on corneal endothelial cell density (ECD) in eye bank donors. METHODS: This is a retrospective study of 287 corneas from donors with causes of death secondary to motor vehicle accident with sustained head trauma (n = 50), gunshot wound to the head (n = 138), fall with sustained head trauma (n = 2), and non-head-related traumatic causes of death (n = 97). Donors older than age 50 years were excluded due to concern for undiagnosed Fuchs endothelial dystrophy as a potential confounder for the cause of endothelial cell loss. Donor characteristics, ECD, and focal endothelial cell loss on specular microscopy were compared between the groups. Donors in the head trauma and nonhead trauma groups were matched by age; there were 42 age-matched donors in both groups. RESULTS: Age and ECD were negatively correlated (Pearson correlation coefficient = -0.57). Death-to-preservation time was not significantly different between the 2 groups ( P value = 0.59). The mean ECD in the head trauma group was 2859 ± 370 cells/mm 2 and 3041 ± 464 cells/mm 2 in the nonhead trauma group. The head trauma group had a lower ECD (178 ± 70 cells/mm 2 , P value = 0.013). After matching for age, the difference in ECD between the 2 groups was -94 ± 82 cells/mm 2 ( P value = 0.26). The adjusted odds of having focal endothelial cell loss was not statistically significant ( P value = 0.50) between the groups. CONCLUSIONS: After statistical adjustments, there were no differences between the head trauma and nonhead trauma groups.

Influence of Descemet Membrane Endothelial Keratoplasty Graft Preparation Patterns on Postoperative Clinical Outcome.

PURPOSE: The aim of this study was to quantify preparation difficulties and complications during DMEK graft preparation and their influence on clinical outcome. METHODS: A retrospective evaluation of 214 consecutive DMEK surgeries from the prospective Cologne DMEK database was performed between July 2018 and December 2019. Preparation conditions (such as central and peripheral adherences, tissue fragility, and Descemet membrane splitting) were quantified and divided into 3 groups: easy, difficult, and very difficult preparation. At follow-up (3, 6, and 12 months after DMEK), best spectacle-corrected visual acuity, endothelial cell count (ECC), and rebubbling rates were evaluated and compared between groups. RESULTS: An easy preparation was possible in 41.6% of cases (group 1, n = 89), a difficult preparation of the DMEK graft occurred in 30.8% (group 2, n = 66), and a very difficult preparation occurred in 27.6% (group 3, n = 59). There was no difference between groups for best spectacle-corrected visual acuity at 3, 6, and 12 months ( P = 0.179, P = 0.325, and P = 0.682, respectively) or for ECC at 3 and 6 months ( P = 0.537 and P = 0.606, respectively). Only at 12 months, the ECC was slightly significant between groups ( P = 0.045). Regarding the rebubbling rate, there was no difference ( P = 0.585). 17.9% of eyes from group 1, 25.7% of eyes from group 2, and 23.7% of eyes from group 3 received at least 1 rebubbling. CONCLUSIONS: These data suggest that difficult preparation conditions do not lead to any worsening of visual acuity or rebubbling rate in the 1-year outcome after DMEK. The endothelial cell density at 12 months showed slightly poorer results in the cases of very difficult preparation.

Comparison of Pre-Descemet Endothelial Keratoplasty and Descemet Membrane Endothelial Keratoplasty in Endothelial Decompensation.

PURPOSE: The purpose of this study was to compare the outcomes of pre-Descemet endothelial keratoplasty (PDEK) and Descemet membrane endothelial keratoplasty (DMEK) in cases of endothelial decompensation. METHODS: This was a prospective, randomized, interventional study conducted at a tertiary eye hospital in North India. Thirty eyes of 28 patients with corneal decompensation were randomly subjected to PDEK (n = 15 eyes) and DMEK (n = 15 eyes). Preoperative demographic details, surgical indications, uncorrected distance visual acuity, corrected distance visual acuity, contrast sensitivity, anterior and posterior segment details, intraocular pressure, central corneal thickness, endothelial cell count, and corneal aberrometry tracing on wavefront analysis were recorded. Patients were followed up for 6 months postsurgery. Visual and graft survival outcomes were assessed. RESULTS: Intraoperatively, a surgeon reported better ease of preparation and intracameral handling with PDEK grafts. Both groups showed comparable improvement in visual acuity, contrast, and high-order aberrations. A decrease in central corneal thickness was significantly higher in DMEK (196 ± 26 vs. 140 ± 14 µm) patients. DMEK grafts were significantly thinner than PDEK grafts at the 6-month follow-up (16 ± 2.17 vs. 27.2 ± 1.93 µm). Endothelial cell loss (35% in DMEK vs. 33.4% in PDEK, P = 0.48) and rise of intraocular pressure (from 15.33 ± 2.85 mm Hg to 15.53 ± 2.2 mm Hg in the DMEK group vs. from 14.6 ± 1.99 mm Hg to 16.2 ± 1.43 mm Hg in the PDEK group) were comparable. Rebubbling rates were higher in the DMEK group (3/15, 20%) compared with the PDEK group (1/15, 6.66%; P = 0.165). CONCLUSIONS: DMEK and PDEK were comparable for both quantitative and qualitative visual outcomes and anatomically for graft survival at the 6-month follow-up.

Pathophysiology of Corneal Endothelial Cell Loss in Dry Eye Disease and Other Inflammatory Ocular Disorders.

PURPOSE: Dry eye disease (DED) and other inflammatory ocular disorders have been reported to be associated with decreased corneal endothelial cell density (CECD), however the mechanism of underlying endothelial cell loss remains unknown. METHODS: We conducted a comprehensive literature search of English-written publications on dry eye disease, corneal endothelial cell loss, Sjögren's syndrome, and Graft Vs Host Disease (GVHD), to review the effects of DED and other inflammatory ocular surface conditions on CECD. RESULTS: A total of 78 studies were included in our study. Loss of corneal neurotrophic support, cytotoxic stress, and a heightened immune response, all of which may occur secondarily to a common causative agent such as inflammation, are major contributors to reduced CECD. CONCLUSION: More studies are needed to determine how the interrelated pathways of altered corneal nerve function and upregulated expression of inflammatory activity influence corneal endothelial cell loss.

Double-Scroll Formation by Fluid Column Manipulation in Preloaded DMEK Grafts Prepared From Younger and Older Donor Tissue.

PURPOSE: The purpose of this study was to determine whether manipulation of preloaded single-scroll Descemet membrane endothelial keratoplasty (DMEK) grafts within the fluid column of an injector can safely and reliably result in formation of double-scroll DMEK grafts and whether there are differential effects on younger versus older donor tissue. METHODS: Pairs of DMEK grafts prepared from older (65-80 years) and younger (48-64 years) donors were preloaded into a Straiko modified Jones tube. One member of the pair was manipulated within the fluid column to form a double-scroll graft, and the other remained unmanipulated. Outcomes measured include success rate for double-scroll formation, endothelial cell loss (ECL), and relative scroll width. RESULTS: Older donor grafts formed double scrolls with a 100% success rate. ECL of older donor manipulated grafts was statistically higher than that of unmanipulated mate grafts (17.4% ± 3.5% vs. 13.0% ± 4.2%, P = 0.03), but was still within the acceptable range for transplant. Younger donor grafts were successfully manipulated into double scrolls with a 67% success rate, and there was no difference in the ECL of manipulated and unmanipulated grafts (15.5% ± 4.4% vs. 13.0% ± 4.5%, P = 0.24). For all grafts and conformations, there was a significant relationship between relative scroll width and ECL ( P < 0.01). CONCLUSIONS: Fluid column manipulation can be used reliably to form double-scroll DMEK grafts. For younger donor grafts, manipulation yields a double scroll without increasing ECL. For older donor grafts, manipulation results in a minimal, acceptable increase in ECL. Surgeons should weigh the advantage of an easily opened graft against the risk of increased ECL when considering this technique.

Clinical Outcomes of Preloaded Descemet Membrane Endothelial Keratoplasty With Endothelium Inward: A 24-Month Comparative Analysis Between Fuchs Endothelial Corneal Dystrophy and Bullous Keratopathy.

PURPOSE: The aim of this study was to compare long-term clinical outcomes of preloaded Descemet membrane endothelial keratoplasty (DMEK) between Fuchs endothelial corneal dystrophy (FECD) and bullous keratopathy (BK). METHODS: In this single-center retrospective clinical case series, 71 eyes of 64 patients indicated with FECD (62%) or BK (38%) (with or without cataract) were treated with preloaded DMEK grafts between March 2018 and February 2020. Standard DMEK peeling, followed by manual folding of the tissue with endothelium-inward orientation and storing in a preloaded fashion inside a 2.2-mm intraocular lens cartridge. All tissues were delivered using a bimanual pull-through technique, followed by air tamponade. Graft unfolding time, endothelial cell loss, corrected distance visual acuity, central corneal thickness, rebubbling rate, and intraoperative and postoperative complications at 1, 3, 6, 12, and 24 months were recorded. RESULTS: The mean intraoperative graft unfolding time in FECD did not differ from the BK group ( P = 0.6061). Cystoid macular edema did not differ in either group ( P = 0.6866). The rebubbling rate was found to be significantly higher in FECD compared with the BK group ( P = 0.0423). Corrected distance visual acuity significantly improved at the first month after surgery ( P = 0.0012), with no differences between FECD and BK at 24 months ( P = 0.2578). Central corneal thickness was stable postoperatively and showed no differences between the groups ( P = 0.3693). Significantly higher endothelial cell counts were observed in the FECD group at 24 months ( P = 0.0002). CONCLUSIONS: Preloaded DMEK with "endothelium-in" offers acceptable intraoperative time, rebubbling rate, and clinical outcomes in both FECD and BK groups. Patients with FECD show better postoperative clinical outcomes even if the rebubbling rate is relatively high.

Preserflo MicroShunt: Efficacy and Endothelial Cell Density.

PRCIS: A main safety concern associated with new glaucoma implants is corneal endothelial cell loss, which could even be observed in already established procedures. PURPOSE: The purpose of this study was to evaluate the efficacy and corneal safety, especially corneal endothelial cell loss (ECL), after Preserflo MicroShunt implantation. METHODS: A monocentric, prospective clinical observational study of patients with a follow-up of at least 12 months who underwent Preserflo MicroShunt implantation at the Department of Ophthalmology, University Hospital of Düsseldorf, Germany, between January 2020 and October 2021. Endothelial cell density (ECD), the distance between the tip of the implant and the corneal endothelium, and the success of the surgery were analyzed. RESULTS: In total, 14 eyes of 12 patients were included. After a mean follow-up of 20±2.7 months intraocular pressure was significantly reduced by 8.2 mm Hg (P=0.0041); in 28.6% of patients, a revision surgery was necessary. Reduction of preoperative and follow-up ECD was not statistically significant (ECL of 45 cells/mm2, ECDpreoperative=2074±703.6 cells/mm2, ECDlast follow-up=2029±742.3 cells/mm2, P=0.42). A longer intracameral shunt tube length correlated significantly with a higher distance between the shunt tip and corneal endothelium (r=0.61, P=0.036). CONCLUSIONS: Preserflo MicroShunt effectively lowered intraocular pressure without substantial ECL after a minimum follow-up period of 17 months.

Comparison of corneal endothelial cell loss during manual small-incision cataract surgery using viscoelastic-assisted nucleus removal versus continuous balanced salt solution plus technique - Randomized controlled trial.

Purpose: The purpose of this study was to compare and analyze the endothelial cell loss during manual small-incision cataract surgery (MSICS) using the viscoelastic-assisted nucleus removal versus basal salt solution plus technique. Methods: This was a prospective randomized trial of 204 patients who underwent MSICS using viscoelastic-assisted nucleus removal (Group 1- OVD) versus basal salt solution plus technique (Group 2- BSS) at a tertiary eye care hospital in North India from January 2018 to 2021. Of these 204 patients, 103 (50.5%) and 101 (49.5%) were allocated to Group 1 and 2, respectively. The parameters assessed were detailed history, demographics, and anterior and posterior segment details. Visual acuity, intraocular pressure (IOP), keratometry, pachymetry, and endothelial cell density were evaluated preoperatively and postoperatively on day 1 and 30. Results: The mean age of the patients was 64.5 ± 8.2 years (range 48-82 years). There were 129 (63.2%) males and 75 (36.8%) females. The mean LogMAR visual acuity for both groups on day 1 (Group 1- 0.3 ± 0.1, Group 2- 0.5 ± 0.2) and day 30 (Group 1- 0.1 ± 0.2, Group 2- 0.1 ± 0.1) was statistically significant (P < 0.001), and the mean IOP value showed a statistically significant value (P < 0.009) on day 1 in Group 2 (15.0 ± 2.4 mmHg) and on day 30 (P < 0.001) in both the groups (Group 1- 13.6 ± 1.8 mmHg, Group 2- 13.5 ± 2 mmHg). The horizontal and vertical k values also showed a statistically significant difference on day 1 and day 30 (P < 0.001). The mean percentage change of central corneal thickness (CCT) in Group 1 was 17.7% and in Group 2 was 17.4% on day 1, and it was 1.1% on day 30 in both the groups, which was statistically significant (P < 0.001) compared to preoperative values. The percentage change in endothelial cell density on day 1 was 9% in Group 1 and 4.6% in Group 2, which was statistically significant (P < 0.001). On day 30, it was 9.7% and 4.8%, respectively, which was statistically significant (P < 0.001). Conclusion: Our study highlights statistically significant endothelial cell loss with viscoelastic-assisted nuclear delivery compared to BSS-assisted nuclear delivery during MSICS in a short follow-up of 1 month. The CCT values showed a slight increase, and the keratometry and IOP were unaffected compared to the preoperative parameters in both the groups.

Examination of a Modified Graft Preparation Technique to Induce Double-Scroll Formation and Promote the Use of Younger Descemet Membrane Endothelial Keratoplasty Donor Tissue.

PURPOSE: The purpose of this study was to determine whether controlled balanced salt solution (BSS) bursts during graft preparation can safely promote formation of a double-scrolled Descemet membrane endothelial keratoplasty (DMEK) graft in younger donor tissue. METHODS: DMEK grafts prepared from young donor tissue (average age, 55 years; range, 39-66 years) were floated in BSS to spontaneously form scrolls (N = 10 pairs). Controlled BSS bursts were used to promote double-scroll (DS) formation in 1 member of each pair. Grafts were stained, preloaded, and shipped before cell viability analysis. After appropriate training, a less experienced technician performed this technique on 10 additional corneas. Outcomes measured for both technicians include the success rate for obtaining a DS, scroll conformation after shipping, and endothelial cell loss (ECL). RESULTS: There was no difference in ECL between grafts subjected to additional manipulation compared with unmanipulated mate grafts (observer 1: 15.2% ± 3.3% vs. 15.2% ± 4.4%, P = 0.99; observer 2: 16.3% ± 2.9% vs. 15.9% ± 4.5%, P = 0.8). A technician experienced with this technique had a 90% success rate, whereas a less experienced technician had a 70% success rate. The mean ECL of the 10 grafts manipulated by the less experienced technician was not significantly different from results obtained from the experienced technician (observer 1: 18.5% ± 6.0% vs. 15.2% ± 3.3%, P = 0.15; observer 2: 18.1% ± 5.6% vs. 16.3% ± 2.9%, P = 0.34). Scrolls maintained their conformation during shipping events. CONCLUSIONS: Double-scroll graft formation using controlled BSS bursts is a reliable technique that can be performed without causing additional damage to DMEK grafts. This technique may make graft unscrolling easier and can promote the use of younger donor tissue for DMEK.

Quantitative analysis of cornea endothelial cell damage from enucleation, corneal buttoning, and storage in donor corneas using trypan blue dye staining.

We aimed to quantitatively analyze the corneal endothelial cell damage by measuring the area stained with trypan blue dye, and to confirm the degree of corneal endothelial cell damage resulting from enucleation, corneal buttoning, and storage in donor corneas intended for use in human corneal transplantation. This study was a retrospective analysis of medical records and videos recorded during keratoplasty. Twenty-one corneal buttons of 21 donors that underwent endothelial cell staining using trypan blue for the donor preparation during DALK or DMEK were included in the study. The percentage of stained area in entire corneal endothelia and the percentage of the stained area in the 8-mm diameter circle were quantitatively analyzed using Adobe Photoshop. The mean percentage of the stained area in the entire corneal endothelia in 13 corneas was 8.1 ±â€…13.3% (range, 0.0-56.1%), and the mean percentage of the stained area in a circle with a diameter of 8 mm in 21 corneas was 3.4 ±â€…5.2% (range, 0.0-18.9%). The correlations between the death-to-preservation time, the training duration of the residents who performed donor corneal buttoning, and the percentage of the stained area in the 8-mm diameter circle were not significant(P = .441, P = .495, respectively). Cornea thickness and endothelial cell density did not differ between 10 eyes in the group with the percentage of the stained area in a circle with a diameter of 8 mm <5% and 5 eyes in the group with the percentage more than 5% damage (P = .854, P = .358). The corneal endothelial cell damage could be quantitatively analyzed using trypan blue staining before keratoplasty in donor cornea. The amount of corneal endothelial cell damage in the central 8-mm circle was mostly acceptable, but some cases showed significantly severe endothelial cell damage. The corneal thickness and endothelial cell density did not differ between 10 eyes in the group with the percentage of the stained area in a circle with a diameter of 8 mm <5% and 5 eyes in the group with the percentage more than 5% damage. Therefore, pachymetry and specular microscopy are not sufficient for evaluating donor corneas before keratoplasty.