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.

Using a Cone-Shaped Glass Funnel Adapter Reduces Endothelial Cell Loss Caused by Preloading Descemet Membrane Endothelial Keratoplasty Tissue.

PURPOSE: The aims of this study were (1) to compare "front" and "rear" methods for loading Descemet membrane endothelial keratoplasty (DMEK) tissue into both micro-Jones and standard-Jones tubes and (2) to evaluate the efficacy of a cone-shaped glass funnel adapter designed to make loading DMEK tissue safer for corneal endothelial cells. METHODS: The corneal endothelium was stained with 0.06% trypan blue to confirm equivalence between mate corneas. The tissues were then processed using the Iowa Lions Eye Bank standard DMEK protocol. In comparison 1, one mate was loaded into the rear of a micro-Jones or standard-Jones tube and the other was loaded into the front of the same tube. In comparison 2, one mate was loaded into the front of the micro-Jones tube and the other was loaded through the cone-shaped funnel adapter into the rear. All tissues were ejected through the front of the modified Jones tubes and assessed for endothelial cell loss (ECL) with calcein AM staining, FIJI, and Trainable Weka Segmentation; scroll widths were measured digitally. RESULTS: There were no statistically significant differences in ECL between front and rear loading [micro (N = 6 pairs): front 15.74% vs. rear 17.95%; standard (N = 6 pairs): front 19.58% vs. rear 19.17%; all P > 0.05]. DMEK scrolls loaded with the funnel adapter exhibited lower ECL compared with scrolls loaded through the front [micro (N = 8 pairs): front 13.53% vs. loading funnel 2.40%; P < 0.001]. Loading with the adapter was not faster (front 6.66 seconds vs. loading funnel 5.52 seconds; P = 0.24). CONCLUSIONS: Using a cone-shaped DMEK loading funnel may reduce ECL sustained during preloading.

New surgical maneuver to position the graft in a descemet stripping with automated endothelial keratoplasty surgery / Nova manobra cirúrgica para posicionar o enxerto em cirurgia de ceratoplastia endotelial com desnudamento automatizado da Descemet

ABSTRACT Objective: To describe a new surgical maneuver to position the graft in a Descemet Stripping with Automated Endothelial Keratoplasty (DSAEK) surgery. Methods: Case series. Results: This technique allows a correct repositioning of the graft in a minimally invasive way. Conclusion: This new surgical maneuver was successful in manipulating the graft in DSAEK surgery and therefore might be effective and safe.

RESUMO Objetivo: Descrever uma nova manobra cirúrgica para posicionar o enxerto em uma cirurgia de ceratoplastia endotelial automatizada com desnudamento da Descemet. Métodos: Série de casos. Resultados: A técnica permitiu o correto reposicionamento do enxerto de forma minimamente invasiva. Conclusão: Esta nova manobra cirúrgica foi bem-sucedida para manipular o enxerto na cirurgia ceratoplastia endotelial automatizada com desnudamento da Descemet e, portanto, pode ser eficaz e segura.

Ascorbic acid ameliorates corneal endothelial dysfunction and enhances cell proliferation via the noncanonical GLUT1-ERK axis.

BACKGROUND: The pumping function of corneal endothelial cells (CECs) plays a pivotal role in the maintenance of corneal water homeostasis. Corneal endothelial dysfunction (CED) leads to corneal edema and opacity, but with the exception of keratoplasty, no optimal therapeutic strategies have been established for CED. In this study, we aimed to investigate the ameliorative effect of ascorbic acid (AA) on CED and the underlying mechanism of action in the corneal endothelium. METHODS: Rabbit corneal endothelial damage was induced by anterior chamber injection of benzalkonium chloride (BAK). AA was topically administered to the corneal surface, and the transparency and thickness of the cornea were assessed by external eye photography, slit-lamp photography, and ultrasonic pachymetry. To further analyze the mechanism, rabbit CECs and immortalized human CECs (B4G12 cells) were cultured. A ferric reducing/antioxidant and AA (FRASC) assay was performed to measure the AA concentration. Cell proliferation was evaluated by cell counting and bromodeoxyuridine (BrdU) labeling assays, and protein expression was examined by liquid chromatography-mass spectrometry (LC/MS) and immunoblotting. The involvement of glucose transporter 1 (GLUT1) and phospho-ERK was evaluated via GLUT1-siRNA and phospho-ERK inhibitor (PD98059) treatment. INTERPRETATION: We observed that topical AA ameliorates BAK-induced rabbit corneal endothelial damage. Furthermore, we demonstrated that AA is transported into B4G12 cells via GLUT1, and afterward, AA increases ERK phosphorylation and promotes cell proliferation. Our findings indicate that CEC proliferation stimulated via the noncanonical AA-GLUT1-ERK axis contributes to AA-enhanced healing of CED.

Activation of kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2/antioxidant response element pathway by curcumin enhances the anti-oxidative capacity of corneal endothelial cells.

Fuchs endothelial corneal dystrophy is one of the most common indications for corneal transplantation, and impaired anti-oxidative function is observed in corneal endothelial cells (CECs). Curcumin is well-known for its anti-oxidative property; but, no study has examined the effect of curcumin on anti-oxidative therapeutic roles in corneal endothelial disease. In our experiments, oxidative stress 0.25 mM tert-butyl hydroperoxide for 2 h was induced in immortalized human CECs pretreated with curcumin. Cell behavior and viability, reactive oxygen species production, and the protein expression of the kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2(Nrf2)/antioxidant response element (ARE) pathway were examined; the Keap1/Nrf2/ARE pathway is crucial anti-oxidative pathway of curcumin. The results showed that pretreatment with 12.5 µM curcumin significantly reduced the ROS production and improved the survival of CECs under oxidative stress. In addition, curcumin pretreatment significantly increased the expression of nuclear Nrf2, and the productions of superoxide dismutase 1 and heme oxygenase-1, which were the target anti-oxidative enzymes of the Keap1/Nrf2/ARE pathway. Our findings showed that curcumin enhanced the growth and differentiation of CECs under oxidative stress. The activation of Keap1/Nrf2/ARE pathway by curcumin was crucial for CECs to improve their anti-oxidative capacity.

Proline-assisted Tube Insertion Through Sulcus in Ahmed Valve.

To prevent corneal endothelial cell loss, ciliary sulcus tube insertion is preferred for the pseudophakic eye. However, we sometimes encounter technical difficulties when inserting the tube through the sulcus. Even in cases in which we are able to insert a 23-G needle through the sulcus into the space between the iris and intraocular lens, the tube of Ahmed valve may stray into the vitreous cavity or under Elschnig pearls. To remedy such conditions, we developed a new tube insertion method using a 4-0 proline stent as a guide to insert the tube in the appropriate position.

Factors influencing the reduction in corneal endothelial cells after Ex-Press® surgery.

PURPOSE: We investigated the factors that influence the reduction in corneal endothelial cells after Ex-Press® surgery. METHODS: This was a retrospective study. We included patients who had undergone Ex-Press surgery and were followed up for > 2. We analyzed the corneal endothelial cell density (ECD) before and after Ex-Press surgery. We investigated the insertion position (Ex-Press device was inserted into cornea or trabecular meshwork (TM)), Ex-Press-iris touch, cornea-iris touch, peripheral anterior synechiae, history of trabeculotomy, history of selective laser trabeculoplasty, type of glaucoma, and simultaneous cataract surgery as influencing factors. We used multivariate analysis to determine the factors influencing the reduction rate of ECD. RESULTS: We included 129 eyes. The mean of ECD had decreased 7.0% at 2 years. Ex-Press surgeries significantly decreased the ECD after 2 years (p = 0.0118). As a result of the multivariate analysis, the factor that led to a significantly faster reduction in ECD was the insertion position of the Ex-Press (p < 0.0001). The reduction rate of ECD after 2 years in cases of insertion into the cornea (27 eyes) was 15.1 ± 3.6%, and in cases of insertion into a TM (102 eyes), it was 5.2 ± 1.4%. CONCLUSIONS: Insertion into the cornea was a risk factor for rapid ECD loss. The Ex-Press should be inserted into a TM for long-term protection of the corneal endothelial cells.

A Deep Learning Approach in Rebubbling After Descemet's Membrane Endothelial Keratoplasty.

PURPOSE: To evaluate the efficacy of deep learning in judging the need for rebubbling after Descemet's endothelial membrane keratoplasty (DMEK). METHODS: This retrospective study included eyes that underwent rebubbling after DMEK (rebubbling group: RB group) and the same number of eyes that did not require rebubbling (non-RB group), based on medical records. To classify the RB group, randomly selected images from anterior segment optical coherence tomography at postoperative day 5 were evaluated by corneal specialists. The criterion for rebubbling was the condition where graft detachment reached the central 4.0-mm pupil area. We trained nine types of deep neural network structures (VGG16, VGG19, ResNet50, InceptionV3, InceptionResNetV2, Xception, DenseNet121, DenseNet169, and DenseNet201) and built nine models. Using each model, we tested the validation data and evaluated the model. RESULTS: This study included 496 images (31 eyes from 24 patients) in the RB group and 496 images (31 eyes from 29 patients) in the non-RB group. Because 16 picture images were obtained from the same point of each eye, a total of 992 images were obtained. The VGG19 model was found to have the highest area under the receiver operating characteristic curve (AUC) of all models. The AUC, sensitivity, and specificity of the VGG19 model were 0.964, 0.967, and 0.915, respectively, whereas those of the best ensemble model were 0.956, 0.913, and 0.921, respectively. CONCLUSIONS: This automated system that enables the physician to be aware of the requirement of RB might be clinically useful.

Recent Surgical Trends in Pediatric Corneal Transplantation: A 13-Year Review.

PURPOSE: Corneal transplantation is the standard of care for pediatric corneal opacities, but little consensus exists on optimal surgical management. Our goal was to evaluate cross-sectional data of donor and recipient characteristics collected from eye banks providing tissue for pediatric corneal transplant cases to assess surgical trends in pediatric keratoplasty over the past 13 years. METHODS: We performed a retrospective review of recipient data, collected from 4 major eye banks, for pediatric patients (<18 years) who underwent corneal transplantation between January 2005 and December 2017. We analyzed trends in surgical indications, types of keratoplasty, and donor/recipient characteristics. RESULTS: Our database included 2620 total pediatric cases. Penetrating keratoplasty (PKP) remains the most common surgery performed (79.8%), but more partial-thickness transplant cases [eg, endothelial keratoplasty (EK)] have been performed since 2008. The most commonly reported transplant indication was ectasias/thinnings (34.1%) overall and congenital opacities (17.0%) in children less than 5 years. Average donor age was significantly lower for the youngest recipient age group of less than 5 years (P < 0.001); endothelial cell count was also higher, and death-to-surgery time was lower for PKP and EK cases versus other keratoplasties. CONCLUSIONS: Indications for transplant vary across age groups but are consistent with previous reports. Popularity of partial-thickness transplants has increased since 2008. Surgeons prefer younger donor tissue for younger patients and have higher thresholds for endothelial cell count for PKP and EK cases. Centralized tracking of pediatric keratoplasty cases is necessary for further investigation of long-term outcomes.

Perioperative Use of Rho-Kinase Inhibitors has Beneficial Effect on Corneal Endothelium after Phacoemulsification.

PURPOSE: Does perioperative use of Rho-Kinase (ROCK) inhibitors have beneficial effect on corneal endothelial cells after phacoemulsification? SETTING: This study was conducted at King Abdulaziz University Hospital in Riyadh. DESIGN: This was a prospective study assessing the effect of ROCK inhibitors on corneal endothelium after phacoemulsification. METHODOLOGY: Three patients have used ROCK inhibitor 1 day before and 1 week after phacoemulsification surgery, and specular microscopy and Pentacam were done preoperatively and 3 months postoperatively. RESULTS: Endothelial cell density decreased to 11.3%, 9.45%, and 4.09% in eyes with ROCK inhibitors and 23.9% in one eye without ROCK inhibitor. CONCLUSION: Perioperative ROCK inhibitor use has a possible protective effect on corneal endothelium.

Minimizing Endothelial Cell Loss Caused by Orientation Stamps on Preloaded Descemet Membrane Endothelial Keratoplasty Grafts.

PURPOSE: To quantify endothelial cell loss (ECL) caused by orientation stamps on prestripped and preloaded Descemet membrane endothelial keratoplasty (DMEK) grafts, and to examine a method for reducing ECL using a smaller stamp. METHODS: Ten prestripped and 10 preloaded DMEK grafts were prepared with S-stamps. Ten additional preloaded DMEK grafts were prepared with both an S-stamp and a smaller F-stamp in different paracentral areas of the graft. The footprint of each stamp was measured using ink on cardstock. DMEK grafts were stored in viewing chambers filled with 20 mL of Optisol-GS for 3 days at 4°C. ECL was quantified using Calcein-AM staining and FIJI Weka Segmentation. RESULTS: S-stamps on prestripped DMEK grafts contributed an average ECL of 1.1% ± 0.5% (range: 0.6%-2.2%) toward total graft damage, whereas S-stamps on preloaded DMEK grafts contributed approximately twice that amount (average ECL: 2.0% ± 0.7%, range: 1.3%-3.1%, P = 0.004). Overall ECL for prestripped grafts (average: 7.1% ± 3.3%, range: 3.3%-13.7%) and preloaded grafts (average: 11.3% ± 4.2%, range: 6.9%-19.4%) was similar to previous reports. The footprint of the S-stamp was approximately 45% larger than that of the F-stamp. In 10 preloaded grafts marked with both stamps, the S-stamp caused an average ECL of 1.9% ± 0.6% (range: 1.2%-3.2%), whereas the smaller F-stamp caused an average ECL of 1.0% ± 0.2% (range: 0.8%-1.4%, P = 0.0002). CONCLUSIONS: Loss of endothelial cells associated with graft-stamping was greater in preloaded tissue than in prestripped tissue and was less with a smaller F-stamp than with a larger S-stamp. Using a smaller stamp could help minimize ECL in prestripped and preloaded DMEK grafts.

New ex vivo model of corneal endothelial phacoemulsification injury and rescue therapy with mesenchymal stromal cell secretome.

PURPOSE: To develop a reproducible ex vivo model of corneal endothelial cell injury using phacoemulsification in porcine eyes and to evaluate the effects of mesenchymal stromal cell secretome in this injury model. SETTING: Department of Ophthalmology, University of Illinois at Chicago, Illinois, USA. DESIGN: Experimental study. METHODS: A corneal endothelial injury model was optimized using different powers and durations of ultrasound energy inside ex vivo porcine eyes. Conditioned media from corneal mesenchymal stem cells was collected under serum-free conditions from passages 4 to 6. Immediately after the phacoemulsification injury, the anterior chamber fluid was replaced with unconditioned media or conditioned media and incubated at 37°C for 4 hours. At the end, endothelial cell viability was evaluated using trypan blue staining and analyzed with ImageJ software. RESULTS: Using specific parameters (50% power for 30 seconds), phacoemulsification inside fresh porcine eyes led to a consistent level of endothelial cell injury. Incubation with corneal mesenchymal stromal cell-conditioned media after the injury significantly reduced endothelial cells loss compared with unconditioned media (mean 1.29% ± 0.91% [SD] and 5.33% ± 3.24%, respectively, P < .05). CONCLUSIONS: Phacoemulsification inside fresh porcine eyes provided a reproducible model to study endothelial cell injury. Treatment with corneal mesenchymal stromal cell secretome after injury appeared to significantly enhance the survival of corneal endothelial cells. This might provide a new strategy for preventing corneal endothelial cell loss after phacoemulsification or other endothelial injuries. Further in vivo studies are necessary to determine the therapeutic potential.

Comparing Outcomes of Phacoemulsification With Femtosecond Laser-Assisted Cataract Surgery in Patients With Fuchs Endothelial Dystrophy.

PURPOSE: To compare the outcome in patients with Fuchs endothelial dystrophy (FED) who underwent standard phacoemulsification vs femtosecond laser-assisted cataract surgery (FLACS) in the treatment of visually significant cataracts. DESIGN: Retrospective, comparative, interventional case series. METHODS: Patient or Study Population: Between April 2013 and December 2016, 140 FED eyes with cataracts of all densities were included. Seventy-two eyes underwent phacoemulsification and 68 eyes underwent FLACS. Intervention or Observation Procedures: Automated noncontact specular microscopy was performed at baseline and postoperatively over a mean of 17.91 ± 10.47 months. Parameters collected include visual acuity, slit-lamp examination findings, and intraoperative findings. MAIN OUTCOME MEASURES: Pachymetry, endothelial cell density (ECD), and coefficient of variance (COV) were compared. RESULTS: Phacoemulsification had significantly greater postoperative median loss of ECD of 229.0 cells/mm2 (14.2%) compared to FLACS ECD of 133.0 cells/mm2 (6.5%) (U = 1343.0, Z = -2.241, P = .025). Mean loss of ECD was 346.524 ± 420.472 cells/mm2 and 119.964 ± 434.882 cells/mm2 for phacoemulsification and FLACS, respectively (P = .005). Mean percentage loss of ECD was 15.3% ± 17.5% for phacoemulsification and 4.4% ± 25.0% for FLACS (P = .006). Eyes that underwent phacoemulsification had 10.7% ± 15.4% mean ECD loss in the mild cataract group, and in the moderate/hard cataract group 19.5% ± 18.0%, P = .045. Eyes that underwent FLACS had 0.9% ± 22.5% mean ECD loss in the mild cataract group, and 8.2% ± 26.3% in the moderate/hard cataract group, P = .291. Comparison between procedures of mean ECD loss for moderate/hard cataracts was significant (P = .043). CONCLUSIONS: FLACS is shown to be superior to phacoemulsification in reducing postoperative endothelial cell loss in FED patients, which translates to a lower risk of corneal decompensation, especially in patients with moderate/hard cataract densities.

Application of thermoreversible hydrogel (poloxamer 407) to protect the corneal endothelium during phacoemulsification in porcine and rabbit eyes.

PURPOSE: To evaluate the effectiveness of thermoreversible (poloxamer) hydrogels as a substitute for ophthalmic viscosurgical devices (OVDs) during phacoemulsification in porcine and rabbit eyes and compare their endothelial protective effect with that of hyaluronic acid-based OVDs. SETTING: Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, South Korea. DESIGN: Experimental study. METHODS: Fluorescein-stained poloxamer hydrogels (20%, 22%, 24%, and 26% [weight/weight%]) and cohesive (sodium hyaluronate 1.0% [Provisc]) and dispersive (sodium hyaluronate 3.0%-chondroitin sulfate 4.0% [Viscoat]) OVDs were injected into the anterior chamber of porcine eyes incubated at 32°C. In the in vitro study, the retention time was measured in 3 groups of 45 porcine eyes during continuous phacoemulsification. In the in vivo study, the endothelial cell count (ECC) was measured before and 3 days after intermittent phacoemulsification in 12 rabbit eyes randomized to a poloxamer hydrogel or a dispersive OVD group. RESULTS: The optimum concentration of thermosensitive hydrogel was 26%, at which no gel-to-sol phase transition occurred in the anterior chamber, with a 21°C irrigation solution. In the in vitro study, the mean retention times were 5.53 seconds ± 1.77 (SD), 125.00 ± 29.34 seconds, and 221.53 ± 42.48 seconds in the cohesive OVD, dispersive OVD, and 26% poloxamer hydrogel groups, respectively (P < .001). Throughout the 5-minute intermittent phacoemulsification, the 26% poloxamer hydrogel remained in the anterior chamber as a semisolid gel. In the in vivo study, the mean decrease in ECC was significantly lower in the 26% poloxamer hydrogel group than in the dispersive OVD group (P = .029). CONCLUSION: Thermoreversible hydrogels might be suitable substitutes for hyaluronic acid-based OVDs for corneal endothelial protection during phacoemulsification.

The protective effect of simvastatin against ultraviolet B-induced corneal endothelial cell death.

Purpose: Excessive ultraviolet B (UVB) exposure causing corneal endothelium injury, including apoptosis, is a serious condition. Therefore, drugs that can inhibit apoptosis in corneal endothelial cells represent an effective strategy. Simvastatin is widely used as a specific inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA reductase, can reduce levels of low density lipoprotein (LDL) cholesterol, and exerts anti-inflammatory effects. However, the protective effect of simvastatin on corneal endothelial cells remains unclear. Therefore, the aim of this study was to elucidate whether UVB promotes the initiation of apoptosis in corneal endothelial cells and injury reversible by simvastatin treatment. Methods: We detected the cell viability, subG1 population, and caspase-3 activity. Results: Results showed that simvastatin alleviates UVB-induced cell death, cell apoptosis, and caspase-3 activity. Conclusion: Our findings indicated that simvastatin alleviated UVB-induced corneal endothelial cell apoptosis via caspase-3 activity.

Effect of Diabetes Mellitus and Metformin on Central Corneal Endothelial Cell Density in Eye Bank Eyes.

PURPOSE: To determine whether metformin use and diabetes mellitus (DM) affect central corneal endothelial cell density (ECD) by examining an eye bank corneal donor database. METHODS: The Lions Eye Institute corneal donor database, which consists of 38,318 corneal samples, was examined. Associations of ECD with metformin use and DM were tested by mixed effects linear models that account for correlations of outcomes between eyes within subjects adjusting for age, intraocular lens status, and glaucoma. Subjects (N = 17,056) with observed ECD counts for both eyes are included for analysis. RESULTS: Average donor age was 56.3 (SD = 15.0). ECD was not associated with metformin use (mean ± SE = 2592 ± 11.9 (N = 1014) versus nonuse [2592 ± 3.0 (N = 16,042), P = 0.302]; further analysis showed that ECD was not significantly associated with metformin use in patients with diabetes. However, metformin use was significantly associated with lower ECD among patients with glaucoma: [2658 ± 50.7 (N = 27) for use versus 2789 ± 19.0 (N = 164) for nonuse, P = 0.018]. The presence of DM was significantly associated with lower ECD 2581 ± 5.6 (N = 4766) for DM versus 2595 ± 3.4 (N = 12,290) for non-DM, P = 0.031). CONCLUSIONS: Lower ECD was associated with DM. Lower ECD was not associated with metformin use except in a subgroup of patients with glaucoma, in which subgroup analysis showed lower ECD. The differences in ECD observed were small and unlikely to affect the suitability for transplantation of donor corneas.

Reduction of Donor Cornea Exposure to Repeat Warming Cycles and Evaluation Times After Implementation of a Rapid Warming Protocol.

PURPOSE: To compare tissue evaluation times and specular image quality before and after the implementation of rapid tissue warming at a single eye bank. METHODS: This retrospective study compares the evaluation of 494 donor corneas. All corneas were stored in Optisol-GS. Group 1 contained 247 corneas evaluated immediately before implementation of a tissue incubator and tissue warming protocol. Group 2 contained 247 corneas evaluated immediately after implementation. Total evaluation times (including specular microscopy, optical coherence tomography for corneal thickness measurements, and 2 slit-lamp examinations) were calculated and compared. Representative specular images of donor corneas were rated and compared using a previously described scale by 2 masked readers. RESULTS: Donor tissue characteristics were not significantly different between both groups (age, P = 0.87; sex, P = 0.93; endothelial cell densities, P = 0.47; and death-to-preservation times, P = 0.18). The mean total evaluation time for group 2 corneas was ∼3 hours, with 97% (201/208) of evaluations completed on the same day. In contrast, only 73% (164/225) of corneas from group 1 were completely evaluated in 1 day, and the mean evaluation time for those corneas was ∼4.25 hours (P < 0.01). Specular images of corneas from group 2 were rated 1 grade higher, on average, than those from group 1 (n = 247 in each group, P < 0.01). Furthermore, 71% of specular images from group 2 were categorized as "good" or "excellent" quality, whereas only 30% of corneas from group 1 received those ratings. CONCLUSIONS: Rapid tissue warming cuts down on tissue evaluation time and reduces the time donor corneas are out of cold storage. Better specular images were obtained after implementation of the rapid warming protocol.

Hypoxia and the Prolyl Hydroxylase Inhibitor FG-4592 Protect Corneal Endothelial Cells From Mechanical and Perioperative Surgical Stress.

PURPOSE: To determine whether hypoxia preconditioning can protect corneal endothelial cells from mechanical stress and perioperative procedures mimicking Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Preconditioning was delivered by 2 hours of 0.5% oxygen incubation in a hypoxia chamber or by exposure to the prolyl hydroxylase inhibitor FG-4592, which prevents hypoxia-inducible factor-1 alpha degradation. Damage to whole corneas was produced by brief sonication. To mimic use with DSAEK, FG-4592-preconditioned and control donor corneas were dissected with a microkeratome, and the posterior donor button was pulled through a transplant insertion device (Busin glide). The area of endothelial damage was determined by trypan blue staining. RESULTS: In all cases, hypoxia preconditioning or incubation with FG-4592 protected corneal endothelial cells from death by mechanical stress. Hypoxia-preconditioned human and rabbit corneas showed 19% and 29% less cell loss, respectively, relative to controls, which were both significant at P < 0.05. FG-4592 preconditioning reduced endothelial cell loss associated with preparation and insertion of DSAEK grafts by 23% relative to the control (P < 0.01). CONCLUSIONS: These results support the hypothesis that preconditioning by hypoxia or exposure to FG-4592 improves corneal endothelial cell survival and may also provide protection during surgical trauma.

Modified Descemet's stripping automated endothelial keratoplasty for eyes with glaucoma drainage devices and shallow anterior chambers.

PURPOSE: To present a modified Descemet's stripping automated endothelial keratoplasty (DSAEK) technique to avoid risks of endothelial cell loss related to the presence of a glaucoma tube in cases with shallow anterior chamber. METHOD: A 72-year-old patient with an only eye and corneal decompensation secondary to a Baerveldt tube was referred for keratoplasty. He was pseudophakic and had shallow anterior chamber. His best-corrected visual acuity was counting fingers close to face. He underwent a combined procedure with withdrawal and shortening of tube followed by a modified DSAEK employing a 7.5-mm donor graft in which a peripheral notch was performed to overlay the silicon tube. RESULTS: No intraoperative or postoperative complications were noted. The endothelial cell count was 2000/mm2 after 15 months of the surgery. His best-corrected visual acuity remains 6/18 with a stable glaucoma. CONCLUSION: This modified technique of DSAEK offers the benefits of endothelial transplant, and it could represent an option to reduce risks of corneal decompensation due to the presence of tubes in cases with shallow anterior chambers.

Preoperative photocoagulation reduces corneal endothelial cell damage after vitrectomy in patients with proliferative diabetic retinopathy.

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes and is a leading cause of visual decline and irreversible blindness. So we designed this study to investigate retrospectively the effect of preoperative photocoagulation on corneal endothelial cells after vitrectomy in patients with PDR.The study included 52 eyes of 46 patients with PDR complicated with vitreous hemorrhage, who underwent vitrectomy. Patients were apportioned to a photocoagulation group (26 eyes/23 patients) or nonphotocoagulation group (26/23 patients), according to their history of preoperative photocoagulation. A specular microscope was used to assess the corneal endothelial cell density and percentage of hexagonal cells (PHC) before surgery, and at 1 week, 1 month, and 3 months after surgery.The cell density was lower 3 months after surgery in the photocoagulation group, but at 1 month in the nonphotocoagulation group, all cases were significantly different from the preoperative value (P < .05 or P < .01). One week after surgery, the mean cell densities between the photocoagulation and nonphotocoagulation groups were not statistically different (P > .05). However, the mean cell densities at 1 and 3 months after surgery in the photocoagulation group were significantly higher than those in the nonphotocoagulation group (P < .05). The PHC values in the photocoagulation group at 1 week and in the nonphotocoagulation group at 1 week, 1 month, and 3 months were much lower than their respective preoperative values (P < .05 or P < .01). More importantly, at 1 and 3 months, the PHC had recovered to preoperative values in the photocoagulation group, but not in the nonphotocoagulation group. As for cell density and PHC, they were both significantly higher 1 and 3 months after surgery in the photocoagulation group than in the nonphotocoagulation group (P < .05).Photocoagulation before vitrectomy reduces subsequent corneal endothelial cell damage in PDR patients.