Chamber shallowing technique for challenging DMEK cases: Tucking cellulose spears under the speculum to augment posterior pressure.

Some anterior chambers do not readily shallow because of insufficient posterior pressure and/or very deep anterior chamber anatomy, which can make unscrolling descemet membrane endothelial keratoplasty (DMEK) tissue more challenging with an unmodified tap technique. We present a hands-free method for augmenting posterior pressure by temporarily tucking cellulose sponges under the blades of the eyelid speculum. The sponges transfer some of the eyelid speculum's weight onto the bulbar surface posterior to the iris, thereby indenting the sclera and causing the iris diaphragm to bulge further forward. This hands-free technique can transform a potentially challenging DMEK case into a more straightforward one by facilitating both a shallow anterior chamber and a bimanual unscrolling technique. However, it only works in bicameral eyes with a vitreous body (e.g., an eye with penetrating keratoplasty, vitreous syneresis, and axial myopia) and will not work in unicameral eyes after vitrectomy (e.g., an eye with an Anterior Chamber Intraocular Lens (ACIOL)).

Quantitative Assessment of Subjective Symptoms and Corneal Sensitivity in Chronic Orbital Pain Patients.

PURPOSE: To objectively evaluate the subjective symptoms and characteristics of chronic orbital pain as well as to quantify sensitization of peripheral trigeminal nerves. METHODS: In this prospective cohort study, patients who previously showed a response to peripheral trigeminal nerve blocks for unilateral, idiopathic chronic orbital pain and healthy subjects completed validated questionnaires assessing headaches, neuropathic signs and symptoms, photophobia, and pain qualities. Corneal sensitivity was measured in both eyes for all subjects with a Cochet-Bonnet aesthesiometer. For pain patients, the full assessment protocol was repeated 2-4 weeks after the study injection, and corneal sensitivity was also measured 30 minutes postinjection. Outcomes assessed were headache, neuropathic pain, and photophobia scores; pain qualities; and corneal sensitivity. RESULTS: Six female chronic orbital pain patients (mean age 48.2 years) and 11 female controls (mean age 47.5) were included. The mean headache, neuropathic pain, and photophobia questionnaire scores were significantly higher for pain patients than for controls (p < 0.001). On sensory testing, 5 pain patients (83.3%) endorsed allodynia, and all 6 (100%) had hyperalgesia in the ipsilateral frontal nerve dermatome. No controls had allodynia or hyperalgesia. Corneal sensitivity was similar between eyes in pain patients and between groups. Questionnaire scores and corneal sensitivity did not change significantly after the injection. CONCLUSIONS: Chronic orbital pain patients have a measurable reduction in quality of life due to headaches and photophobia. The supraorbital and supratrochlear nerves are sensitized, resulting in cutaneous hypersensitivity in the corresponding dermatome, but corneal nerves have normal sensitivity.

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.

Risk Factors for Fibrous Ingrowth in Eyes Requiring Primary Keratoplasty.

PURPOSE: The aim of this study was to define risks for corneal transplantation associated with fibrous ingrowth among first-time transplant recipients. METHODS: We performed a retrospective case-control study of patients with a histopathologic diagnosis of fibrous ingrowth between 2002 and 2019. Patients with fibrous ingrowth from a first corneal specimen were included. Those with incomplete records were excluded. A 1:2 case-control ratio was used. Controls were matched using surgical indication, surgery year, transplantation method, sex, and age. RESULTS: Seventy-eight eyes (76 patients) were included and matched with 160 control eyes. The incidence of fibrous ingrowth found on a first corneal transplant was 0.6% per year. The most common keratoplasty indications were pseudophakic corneal edema (n = 25, 32%) and aphakic corneal edema (n = 15, 19%). Cases were more likely to have a history of ocular trauma (odds ratio [OR], 2.94; 95% CI, 1.30-6.30; P = 0.007), uveitis (OR, 2.73; 95% CI, 1.12-6.63; P = 0.022), retinal detachment or previous retinal surgery (OR, 2.40; 95% CI, 1.34-4.30; P = 0.003), glaucoma tube-shunt surgery (OR, 2.70; 95% CI, 1.29-5.65; P = 0.007), aphakia (OR, 3.02; 95% CI, 1.61-5.67; P = 0.0004), or iris derangement (OR, 10.52; 95% CI, 5.45-20.30; P <0.0001). A multivariate logistic regression model using iris derangement, history of ocular trauma, history of uveitis, and history of cataract surgery demonstrated 81% sensitivity and 66% specificity in predicting presence of fibrous ingrowth. CONCLUSIONS: A history of ocular trauma, uveitis, retinal detachment or previous retinal surgery, glaucoma tube-shunt surgery, aphakia, and iris derangement are risks for detecting fibrous ingrowth among first-time keratoplasty recipients. Patients with these conditions should be monitored closely for corneal decompensation.

Type II Diabetes Mellitus Causes Extracellular Matrix Alterations in the Posterior Cornea That Increase Graft Thickness and Rigidity.

Purpose: There is a pressing need to investigate the impact of type II diabetes mellitus on the posterior cornea in donor tissues given its increasing prevalence and potential impact on endothelial keratoplasty surgical outcomes. Methods: Immortalized human cultured corneal endothelial cells (CECs; HCEC-B4G12) were grown in hyperglycemic media for 2 weeks. Extracellular matrix (ECM) adhesive glycoprotein expression and advanced glycation end products (AGEs) in cultured cells and corneoscleral donor tissues, as well as the elastic modulus for the Descemet membrane (DMs) and CECs of diabetic and nondiabetic donor corneas, were measured. Results: In CEC cultures, increasing hyperglycemia resulted in increased transforming growth factor beta-induced (TGFBI) protein expression and colocalization with AGEs in the ECM. In donor corneas, the thicknesses of the DM and the interfacial matrix (IFM) between the DM and stroma both increased from 8.42 ± 1.35 µm and 0.504 ± 0.13 µm in normal corneas, respectively, to 11.13 ± 2.91 µm (DM) and 0.681 ± 0.24 µm (IFM) in non-advanced diabetes (P = 0.013 and P = 0.075, respectively) and 11.31 ± 1.76 µm (DM) and 0.744 ± 0.18 µm (IFM) in advanced diabetes (AD; P = 0.0002 and P = 0.003, respectively). Immunofluorescence in AD tissues versus controls showed increased AGEs (P < 0.001) and markedly increased labeling intensity for adhesive glycoproteins, including TGFBI, that colocalized with AGEs. The elastic modulus significantly increased between AD and control tissues for the DMs (P < 0.0001) and CECs (P < 0.0001). Conclusions: Diabetes and hyperglycemia alter human CEC ECM structure and composition, likely contributing to previously documented complications of endothelial keratoplasty using diabetic donor tissue, including tearing during graft preparation and reduced graft survival. AGE accumulation in the DM and IFM may be a useful biomarker for determining diabetic impact on posterior corneal tissue.

Metabolic and proteomic indications of diabetes progression in human aqueous humor.

Diabetes mellitus is a multiorgan systemic disease impacting numerous ocular structures that results in significant ocular morbidity and often results in more frequent corneal and glaucoma surgeries for affected individuals. We hypothesize that the systemic metabolic and proteomic derangement observed in the progression of diabetes influences the composition of the aqueous humor (AH), which ultimately impacts the anterior segment health of the eye. To identify changes associated with diabetes progression, we mapped the metabolite profile and proteome of AH samples from patients with varying severities of type II diabetes (T2DM). Patients were classified as nondiabetic (ND or control), non-insulin-dependent diabetic without advanced features of disease (NAD-ni), insulin-dependent diabetic without advanced features (NAD-i), or diabetic with advanced features (AD). AH samples collected from the anterior chamber during elective ophthalmic surgery were evaluated for metabolite and protein expression changes associated with diabetic severity via gas chromatography/mass spectrometry and ultra-high performance liquid chromatography tandem mass spectrometry, respectively. Metabolic and proteomic pathway analyses were conducted utilizing MetaboAnalyst 4.0 and Ingenuity Pathway Analysis. A total of 14 control, 12 NAD-ni, 4 NAD-I, and 14 AD samples were included for analysis. Elevated levels of several branched amino acids (e.g., valine, leucine, isoleucine), and lipid metabolites (e.g., palmitate) were found only with increasing diabetic severity (i.e., the AD group). Similar proteomic trends were noted in amino acid and fatty acid metabolism and the unfolded protein/stress response. These results represent the first report of both metabolomic and proteomic evaluation of aqueous humor. Diabetes results in metabolic and proteomic perturbations detectable in the AH, and unique changes become manifest as T2DM severity worsens. Changes in AH composition may serve as an indicator of disease severity, risk assessment of anterior segment cells and structures, and potential future therapies.

Primary Graft Failure, Infection, and Endothelial Cell Density in Corneal Transplants With Increased Death-to-Preservation Time.

PURPOSE: To ascertain whether death-to-preservation time (DPT) is associated with donor endothelial cell density (ECD), primary graft failure (PGF), and infection. METHODS: Donor corneas aged older than 10 years with ECD 2000 to 4500 cells/mm2 were procured between 2011 and 2018 by a single eye bank. Donor corneas were analyzed retrospectively for the main outcome measures of PGF, infection, and ECD. Means and proportions of study parameters were compared between corneas with long and short DPT, defined as greater or less than 14 hours, respectively, excluding corneas with a history of intraocular surgery or diabetes. Multivariate analyses were performed using logistic regression, adjusting for donor age at time of death, history of diabetes mellitus, and history of cataract surgery. RESULTS: Among 12,015 corneas, those with long DPT had a statistically but not clinically significant higher ECD than that of corneas with short DPT (2754 vs. 2724 cells/mm2, P < 0.01). There was no difference in PGF and infections in corneas with long versus short DPT (0.28% vs. 0.26%, P = 0.86; 0.43% vs. 0.29%, P = 0.51, respectively). CONCLUSIONS: Longer DPT is not associated with a clinically meaningful reduction in donor ECD, PGF, or infection.

Alleviating an Increasingly Burdened Healthcare System with Telemedicine: Anterior Segment.

Tele-ophthalmology is a rapidly evolving and exciting field that has become increasingly relevant amidst the current global pandemic. With advancements in technology, many components of an evaluation previously possible only in an office setting are becoming possible remotely, paving the way for at-home visits. Examples of these technologies include measurement of visual acuity using smartphones, remote monitoring of intraocular pressure using self-administered tonometers or implantable sensors, and use of digitally acquired slit-lamp or smartphone images for diagnosis of anterior segment pathology. While many examples showcasing the utility of telemedicine have been shown for diseases such as diabetic retinopathy, concerted efforts are needed to develop similar technology for anterior segment diseases. As technology continues to advance, it may be possible to diagnose and manage more anterior segment disease with telemedicine.

Modified dagger-tip Sheets glide to facilitate 2-point fixation across the anterior chamber in aniridic aphakic eyes.

Presented is a modified technique for removing a failed endothelial allograft in an aniridic aphakic eye that reduces the risk of posterior dislocation. This technique involves the creation of an artificial iris plane using a Sheets glide by trimming it into the shape of a dagger so that it can be pulled through the anterior chamber and fixated by both its passage through a paracentesis incision and the main incision. The Sheets glide then acts as a physical barrier, or scaffold, to allow safe removal of the failed endothelial allograft and subsequent repeat endothelial keratoplasty while avoiding posterior dislocation of the tissue into the vitreous cavity.

Tissue Loss, Processing Time, and Primary Graft Failure in Eye Bank-Prepared Descemet Membrane Endothelial Keratoplasty Grafts Before and After Prestripped to Preloaded Graft Transition.

PURPOSE: To examine tissue loss rates, processing time, and primary graft failure (PGF) of "prestripped-only" Descemet membrane endothelial keratoplasty (DMEK) grafts at a single eye bank and how these parameters changed after the introduction of steps to preload tissue among experienced processors. METHODS: Tissue loss and processing time during DMEK graft preparation as well as PGF were analyzed retrospectively at a single eye bank between 2012 and 2018. Outcomes were assessed in consecutive grafts before and after the introduction of preloading to the eye bank's standard operating procedure. RESULTS: A total of 1326 grafts were analyzed, composed of the first 663 preloaded DMEK grafts and, for comparison, the 663 DMEK grafts processed immediately before starting the preloaded service. Mean processing time increased from 17.0 ± 3.9 minutes to 26.0 ± 5.4 minutes with the advent of preloading (P < 0.01). Initially, average processing time increased dramatically, with a maximum processing time of 51 minutes, before regressing to the average. No significant difference in the rate of tissue wastage was observed before versus after the implementation of preloaded DMEK (1.2% vs. 1.7%, P = 0.48). PGF occurred in 7 grafts before the preloaded service and 10 grafts after starting the service (1.6% vs. 2.3%, P = 0.47). CONCLUSIONS: Preloading does not affect tissue wastage for experienced technicians or the PGF rate but increases processing time. Eye banks that are considering adding preloading to their standard operating procedure may need to account for longer processing times in their daily operations.

Eccentrically Punched Descemet Membrane Endothelial Keratoplasty Grafts Expand the Descemet Membrane Endothelial Keratoplasty Donor Pool: One Eye Bank's Reappraisal of the Central Clear Zone Convention.

PURPOSE: To ascertain whether offsetting the Descemet membrane endothelial keratoplasty (DMEK) punch can expand the donor pool in conjunction with prepunched and preloaded services by recapturing the corneas otherwise excluded by the conventional central clear zone criteria. METHODS: In this retrospective review of corneas recovered and processed for DMEK by a single eye bank between March 2017 and October 2018, corneas failing to meet the conventional central clear zone requirement during initial evaluation (defined as an area in the central cornea where an 7.5- to 8.0-mm diameter graft can be obtained free of previous surgical scars, Descemet tears, or confined areas of endothelial defects) were further evaluated for offset punching. Corneas with a central endothelial cell density of at least 2000 cells/mm at the initial screening (average of 3 specular images assessed with the center dot method) that had a clear zone of 7.5- to 8.0-mm diameter where a graft could be obtained were designated as eligible for offset punching for either prepunched or preloaded DMEK. RESULTS: A total of 2607 corneas were found to be suitable for DMEK using the conventional central clear zone criteria. An additional 62 corneas were deemed DMEK suitable by offsetting the punch, yielding a 2.4% increase in the availability of DMEK suitable corneas. CONCLUSIONS: Offsetting the DMEK punch can recapture corneas otherwise excluded from the DMEK donor pool because of a failure to meet the conventional central clear zone criteria, and by our estimation may help eye banks meet the growing demand for DMEK tissue while maximizing the transplant potential of every cornea.

Efficacy of Amphotericin B in Corneal Preservation Media After Extended Frozen Storage.

PURPOSE: To investigate the antimycotic activity of amphotericin B deoxycholate that has been previously frozen for 28 days before supplementation of Optisol-GS. METHODS: Triplicate Optisol-GS samples were inoculated with 10 colony-forming units (CFU) of Candida albicans. Each set of triplicate cultures was supplemented with 2.5 µg/mL of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at -20°C and thawed, or frozen at -20°C for 4 weeks and thawed. The cultures were stored at 4°C, with aliquots taken at 0, 6, 24, and 72 hours for quantification. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at these time points. RESULTS: Six hours after antifungal supplementation, there was a 1.33 log10 CFU reduction with freshly resuspended amphotericin B, compared with a 1.31 log10 reduction with amphotericin B that was frozen overnight (P = 0.20) and a 1.18 log10 reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). After 72 hours, there was a 2.72 log10 CFU reduction with freshly resuspended amphotericin B, a 2.64 log10 CFU reduction with amphotericin B that was frozen overnight (P = 0.45), and a 2.18 log10 CFU reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). CONCLUSIONS: Previously frozen amphotericin B remains highly effective against C. albicans. Optisol-GS supplemented with 2.5 µg/mL amphotericin B that was frozen for 4 weeks at -20°C resulted in >90% CFU reduction by 6 hours and >99% reduction by 72 hours.

Intraoperative fibrin formation during Descemet membrane endothelial keratoplasty.

PURPOSE: To describe Descemet membrane endothelial keratoplasty (DMEK) cases complicated by spontaneous intraoperative fibrin formation. METHODS: DMEK surgeries performed at two centers using a standardized technique were reviewed retrospectively for the occurrence of intraoperative fibrin formation. Cases were assessed for recipient medical history, donor age, best spectacle-corrected visual acuity (BSCVA), intraoperative unscrolling time, 6-month endothelial cell loss (ECL), and the course of the mate donor cornea. RESULTS: In this review of 868 cases of standardized DMEK surgery with surgical peripheral iridotomy, 32 eyes of 29 patients (3.7%) were complicated by the formation of intraoperative fibrin formation, including 3 patients that developed fibrin in both eyes. Three of the 32 grafts failed (9.4%). None of the mate corneas transplanted (n = 27) developed complications related to fibrin. The donor age ranged from 51 to 75 years and recipient age ranged from 49 to 82 years (median, 66 years). Unscrolling time ranged from 1 to 105 min (median, 15 min). Nine eyes required one rebubble procedure. No eyes had vision-limiting comorbidities, and the 6-month BSCVA was ≥20/40 in all eyes. Six-month ECL ranged from 19% to 73% (median, 44%). CONCLUSIONS: We conclude that fibrin formation during DMEK surgery is an uncommon but important complication that can make graft manipulation more difficult, and may have deleterious effects on endothelial cell density and graft survival.

Placoid choroidopathy after bilateral uncomplicated descemet's membrane endothelial keratoplasty.

PURPOSE: To describe a case of bilateral, sequential placoid choroidopathy following uncomplicated Descemet's membrane endothelial keratoplasty (DMEK). OBSERVATIONS: A 49-year old woman presented with flashing lights and central visual field scotomas after undergoing uncomplicated DMEK combined with cataract surgery for Fuch's endothelial dystrophy in the right eye. She was found to have placoid choroidopathy responsive to systemic steroids and for which a comprehensive work-up was unrevealing. Three and a half months later, she underwent DMEK surgery in the fellow eye and again developed placoid choroidopathy in the operated eye. Work-up was again unrevealing and the lesion followed a similar course to the first eye on systemic steroids. Over the course of seven (right eye) and three and a half months (left eye) of follow-up, the uncorrected visual acuity was 20/20 bilaterally and the retinal lesions had modestly improved. CONCLUSIONS AND IMPORTANCE: We report a case of placoid choroidopathy following uncomplicated DMEK combined with cataract surgery in both eyes of a single patient. This case expands upon the reported complications following DMEK surgery and suggests a need to remain aware of posterior segment complications following endothelial keratoplasty.

Novel Use of Telemedicine for Corneal Tissue Evaluation in Eye Banking: Establishing a Standardized Approach for the Remote Evaluation of Donor Corneas for Transplantation.

PURPOSE: To determine the feasibility of using telemedicine consultations in the evaluation of recovered donor corneas for transplant suitability. METHODS: This study aims to establish and test the minimum imaging requirements for telemedical consultations of corneal tissue by remote eye bank medical directors. Digital images from the slit lamp, optical coherence tomography, and/or specular microscope were assembled into telemedical consults and emailed to 4 eye bank medical directors (M.A.T., J.W., C.S.S., N.K.R.). Feedback on the minimum image requirements for each corneal finding was collected. After establishing a standardized imaging and presentation protocol, test cases were presented to the medical directors to examine the validity of these remote consults. To establish a benchmark for the study's parameters, one medical director (J.W.) examined each case in person after his initial remote review. Examiners were masked to each other's responses. RESULTS: Minimum image requirements for determination of corneal findings were defined and were specific to each anatomic layer of the cornea (epithelial, stromal, or endothelial). Using a defined set of digital images for a set of common corneal findings, the rate of agreement between remote evaluators, eye bank staff, and the in-person evaluator was 100% (11 of 11 examples). For ambiguous test cases, remote evaluators agreed on 80% of the cases (4 of 5). CONCLUSIONS: Results from this pilot study suggest that telemedical review of corneal tissue using high-quality digital images may be adequate for accurate identification of specific corneal findings commonly encountered by eye banks.

Prospective evaluation of a novel silicone corneal shield after PRK: 6-month efficacy, safety, and predictability outcomes.

PURPOSE: The aim of this study was to report the 1-week and 6-month refractive outcomes of eyes treated with a novel silicone corneal shield designed to improve visual recovery after photorefractive keratectomy (PRK). PATIENTS AND METHODS: This prospective, observational clinical trial recruited 45 myopic eyes with or without astigmatism at a university eye clinic to undergo wavefront-guided PRK followed by application of an investigational silicone corneal shield that was removed on postoperative day 4. The primary outcome measures were efficacy, predictability, and safety at the 6-month visit. The secondary end points included short-term uncorrected distance visual acuity (UDVA) and pain. RESULTS: No adverse outcomes occurred using the device. At 6 months, 79.5% of eyes achieved UDVA >20/20, 94.9% achieved ≥20/25, and 97.4% achieved ≥20/40. Also, 2.6% lost one line of corrected distance visual acuity and none lost two lines; 71.8% and 97.4% measured within ±0.25 and ±0.50 D of emmetropia, respectively. During the first week, preoperative UDVA improved from 1.34 logarithm of the minimum angle of resolution (logMAR; <20/400 Snellen) to 0.14 logMAR (>20/30) on postoperative day 1 (P<0.0001) and remained stable on days 2-3 (all P>0.05). After removal of the shield on day 4, UDVA declined by two lines before rebounding to 0.16 logMAR (>20/30) on day 7 (both P<0.001). Subjective metrics of pain all peaked between days 2 and 3 before declining. CONCLUSION: The investigational silicone corneal shield is safe and effective when used after PRK and may aid early visual recovery and patient comfort, but comparative studies are needed to validate these preliminary findings. PRECIS: One-week and 6-month refractive outcomes of a novel silicone corneal shield used after PRK show that the device is not only safe and effective but may also speed visual recovery.

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.

Measuring Endothelial Cell Loss on DMEK Grafts After Transplantation in Human Cadaveric Whole Eyes: Description of the Technique and Pilot Study.

PURPOSE: To describe a novel method for analyzing Descemet membrane endothelial keratoplasty (DMEK) graft damage after implantation into human cadaveric donor eyes and to compare results achieved by performing DMEK with a surgeon's long-established technique compared with those of an unfamiliar technique. METHODS: Eight DMEK grafts were implanted into previously frozen human cadaveric eyes. Four grafts were implanted using a Straiko injector and tap technique familiar to the surgeon (C.S.S., 3-yr experience), and 4 grafts were implanted using the Tan EndoGlide and "donor mat device" pull-through technique new to the surgeon. After implanting a DMEK graft and attaching it to the recipient stroma with an air bubble tamponade, the corneoscleral cap was "recovered" from the cadaveric globe using standard techniques. The DMEK graft was stained with Calcein-AM. After staining, a 9.5-mm stromal "carrier button" was punched, and the carrier and graft were transferred to a microscope slide. Grafts were imaged and analyzed using FIJI trainable segmentation. RESULTS: Donor graft characteristics were similar between both groups. Grafts implanted using the surgeon's routine technique showed an average endothelial cell loss (ECL) of 31% ± 4% (n = 3). Grafts implanted using the technique unfamiliar to the surgeon showed an average ECL of 47% ± 24%, but with a trend toward improvement (1 = 76%, 2 = 65%, 3 = 32%, 4 = 17% ECL). CONCLUSIONS: Our proof-of-principle experiment shows that this imaging approach enables quantification of ECL caused by different instruments and surgical techniques after graft implantation. We have used this method to visualize the learning curve of 1 surgeon when learning a new surgical technique.

Viscoelastic Tamponade Applied to the Ocular Surface for Enhanced Control of Gaseous Egress From the Anterior Chamber During Final Bubble Titration in DMEK Surgery: The "Polite" Burp.

PURPOSE: To present a novel technique for enhancing the surgeon's control over the volume of air or gas that is "burped" from the anterior chamber during final bubble and intraocular pressure (IOP) titration in Descemet membrane endothelial keratoplasty. METHODS: After ascertaining that the intracameral bubble is either too large and/or has rendered IOP too high, a bead of ophthalmic viscoelastic is applied to the ocular surface over a paracentesis incision, which is then depressed in the usual fashion to burp gas from the anterior chamber. RESULTS: The weight and viscosity of the viscoelastic create a tamponade that slows the egress of gas from the anterior chamber, thereby making it more controllable. CONCLUSIONS: If the bubble size or IOP needs to be reduced at the conclusion of the Descemet membrane endothelial keratoplasty procedure, application of ophthalmic viscoelastic over the paracentesis can enhance the surgeon's control over the volume of gas burped from the anterior chamber, thereby reducing the tendency to swing between a bubble that is too large or too small.