Search

Purpose: To evaluate ophthalmologists' interest and opinions regarding corneal transplantation and donation in Türkiye. Material and methods: An online questionnaire was prepared using Google Forms, and the electronic link to this questionnaire was sent via WhatsApp to ophthalmologists working in Türkiye. Eighteen open-ended/multiple-choice questions were asked about ophthalmologists' demographic information and their opinions regarding corneal transplantation and donation. The answers were analyzed by transferring the data to Excel. Results: A total of 195 ophthalmologists participated in the survey. While 68.6% of them stated that they wanted to donate their corneas, 21.1% stated that they were undecided, and 10.3% did not want to donate their corneas. While 93.8% of the participants agreed to have a cornea transplant in case of need, 5.7% of them stated that they were undecided, and 0.5% said that they would not accept a cornea transplant. The most frequent (90.5%) reason for being willing to donate one's cornea was to give hope to patients with low vision. The most frequent (46.2%) reason for not wanting to donate one's cornea was the unwillingness to have one's body/eye integrity impaired. The vast majority (80.8%) of the participants thought that there was not enough corneal donation in Türkiye and that this was mostly (85.9%) due to cultural and/or religious reasons. Conclusions: Even in a sample with a high level of education and the most knowledge about corneal transplantation, the willingness to donate corneas may remain below the expected rates. Therefore, it is necessary to alleviate unrealistic concerns and prejudices about corneal donation and transplantation. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to analyse the contamination rate of corneal samples stored in OCM at Lions Eye Bank of Western Australia over a 12-year period. Methods: All OCM samples used to preserve corneas from 2011 to 2022 (inclusive) underwent microbiological testing. Samples were collected into aerobic and anaerobic culture bottles on day 3–5 of corneal preservation and 24 h after transfer to thinning medium. Samples were tested for 7 days using the BACTEC FX system. Corneas remained in quarantine until clearance was obtained. Results: From 2011 to 2022, 3009 corneas were retrieved and 2756 corneas were stored in OCM. Thirty one (1.1%) positive samples were reported, with 20 growths of bacterial origin and 11 fungal. Microbial contamination was mostly identified on day 1 of culture (77.5%). Donors of contaminated samples had a mean age of 55 years, with 17 male and 14 female donors. The highest incidence of contamination came from donors whose cause of death was cancer. Death to enucleation times of contaminated samples ranged from 3.5 to 25.5 h (mean = 13.5 ± 7.3) and death to preservation time ranged from 4.1 to 27.5 h (mean = 14.8 ± 7.2). These did not significantly differ from the average time from death to enucleation (mean = 13.9 ± 3) and death to preservation (mean = 16.3 ± 4.2) of non-contaminated samples. Conclusion: Microbiological screening of corneas stored in OCM at LEBWA showed a very low rate of positive cultures with no predictive donor characteristics. [ABSTRACT FROM AUTHOR]

Purpose: Death-to-preservation time (DTP) is a commonly reported, but infrequently studied, measure of efficiency for the corneal tissue procurement process and is a key screening component for corneal tissue suitability for transplantation. It is unknown whether demographic factors such as race, age, or gender may affect DTP. Methods: This retrospective cross-sectional study included all deceased-donor eye tissue collected by CorneaGen Eye Banks between June 1, 2012 and June 30, 2016. Exposure variables of race, age, and gender were independently analyzed with the outcome variable, DTP, using three simple linear regression analyzes. Associations were then confirmed by a multiple linear regression analysis within a single model. Results: A total of 24,138 unique donors were identified from 48,207 donor eyes. Simple linear regression analysis showed that relative to White donors, Black and Hispanic donors were associated with a 2.40 h (95% CI 2.07–2.74 h, p < 0.001) and 2.48 h (95% CI 2.15–2.80 h, p < 0.001) longer mean DTP, respectively. DTP decreased with increasing age, at a rate of 30 min per every 10 years (95% CI 27–33 min, p < 0.001). Male donors were associated with a 35 min (95% CI 26–44 min, p < 0.001) longer DTP relative to female donors. A multiple linear regression confirmed the results of the three simple linear regressions. Conclusions: In a large cohort of corneal donors, non-White race, younger age, and male gender were associated with longer DTP. [ABSTRACT FROM AUTHOR]

Purpose: The study aims to evaluate the usefulness of lutein/trypan blue vital dye for the staining of corneal tissues and endothelium–Descemet membrane (EDM) for Descemet membrane endothelial keratoplasty (DMEK). Methods: Sixteen human corneal tissues (Eye Bank, Rome, Italy) were used. Corneal endothelium was tested at 25 s (T0), 1 min (T1), 2 min (T2), and 4 min (T4) from dye addition. Staining intensity and cell counting were compared. Stripped EDM was analyzed for selected apoptotic (AP, caspases, BCL2, BAX) and differentiation (VEGF-A, TGF-β1RI, SMAD3/7, SMA) targets and changes in target expression. Protein extracts were analyzed through SDS-PAGE/IB. Results: Although trypan blue staining produced the same color intensity of lutein/trypan blue dye in half the time, lutein/trypan blue reached a good and adequate color intensity at T4, which persisted even on excised and washed EDM grafts. Lutein/trypan blue-stained EDM showed a reduced number of blue-stained cells and AP immunoreactivity was significantly reduced in the same samples. An increased BCL2 transcript and a reduced BAX transcript were detected in lutein/trypan blue-stained EDM. No significant changes were observed for the main effector caspases (3/9) upon both treatments and the target genes representative of endothelial cell trans-differentiation (TGF-β1RI, SMAD3/7, SMA). A trend in vascular endothelial growth factor (VEGF-A) regulation was observed in lutein/trypan blue-treated EDM grafts. Conclusion: Obtained results suggest that lutein/trypan blue dye deserves attention in the DMEK field and support the potential routine use of this dye as a valid alternative to trypan blue for all procedures devoted to the assessment of endothelial cell viability and visualization of EDM graft before DMEK grafting. [ABSTRACT FROM AUTHOR]

To evaluate the reliability and efficiency of sterile pachymetric measurements of donor corneas based on tomographic data using two different methods: a "manual" and a "(semi-)automated" method. Twenty-five (25) donor corneas (50%) stored in MI and 25 (50%) in MII were imaged 5 times consecutively using an anterior segment OCT (AS-OCT). The central corneal thickness (CCT) was measured both with the manual measurement tool of the AS-OCT (= CCTm) and with a MATLAB self-programmed software allowing (semi-)automated analysis (= CCTa). We analyzed the reliability of CCTm and CCTa using Cronbach´s alpha (α) and Wilcoxon signed-Rank Test. Concerning CCTm, 68 measurements (54.4%) in MI and 46 (36.8%) in MII presented distortions in the imaged 3D-volumes and were discarded. Concerning CCTa, 5 (4%) in MI and 1 (0.8%) in MII were not analyzable. The mean (± SD) CCTm was 1129 ± 6.8 in MI and 820 ± 5.1 µm in MII. The mean CCTa was 1149 ± 2.7 and 811 ± 2.4 µm, respectively. Both methods showed a high reliability with a Cronbach´s α for CCTm of 1.0 (MI/MII) and for CCTa of 0.99 (MI) and 1.0 (MII). Nevertheless, the mean SD of the 5 measurements was significantly higher for CCTm compared to CCTa in MI (p = 0.03), but not in MII (p = 0.92). Sterile donor tomography proves to be highly reliable for assessment of CCT with both methods. However, due to frequent distortions regarding the manual method, the (semi-)automated method is more efficient and should be preferred. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the tolerability, safety and efficacy of new lyophilized amniotic membrane (LAM) presentation for ocular use. A prospective case-series cohort of four patients with primary nasal pterygium which undergone excision and LAM implantation was evaluated for complications and clinical outcomes. Surgical manipulation of LAM was also assessed. LAM was stiff and easy to manipulate as well as no tearing occurred during surgery or suturing. Ocular comfort was checked and similar among those patients with LAM glued or sutured. After 12 months, there were no issues about tolerability or adverse events. Lower cosmetic outcomes (recurrence) were stated in 3 patients. Our study showed that LAM could be an effective alternative to cryopreserved amniotic membrane for graft after pterygium excision surgery. Its main advantage, storage at room temperature, can make it of immediate availability. Further studies comparing clinical outcomes of pterygium surgery with cryopreserved amniotic membrane versus LAM would confirm the benefits of the last. [ABSTRACT FROM AUTHOR]

Purpose: To report the impact of establishing and maintaining a high intracameral pressure (ICP) of 200 mmHg on UT-DSAEK graft preparation using an artificial anterior chamber pressuriser (ACP) control unit (Moria SA, Antony, France). Method: Retrospective laboratory and clinical study. Four paired donor corneas were mounted on an artificial anterior chamber and subjected to 70 mmHg ("low") and 200 mmHg ("high") ICP using an ACP system. The central corneal thinning rate was measured after 5 min using AS-OCT and the endothelial cell viability was analysed using trypan blue and live/dead staining following 70 mmHg and 200 mmHg ICP. Visual outcomes and complications in a clinical case series of nine patients with bullous keratopathy who underwent UT-DSAEK using 200 mmHg ICP during graft preparation are reported. Results: Laboratory outcomes showed 2 ± 1% and 2 ± 2% dead cells following 70 mmHg and 200 mmHg ICP respectively. Percentage viability in the 70 mmHg group (52.94 ± 5.88%) was not found to be significantly different (p = 0.7) compared to the 200 mmHg group (59.14 ± 10.43%). The mean corneal thinning rate after applying 200 mmHg ICP was 27 ± 13 μm/min centrally (7.2%/min). In the clinical case series, two cases were combined with cataract surgery. Re-bubbling rate was 11%. At the last follow-up (259 ± 109 days), graft thickness was 83 ± 22 μm centrally, endothelial cell density was 1175 ± 566 cell/mm2 and the BCVA of 0.08 ± 0.12 logMAR was recorded with no episodes of rejection. Conclusion: ACP control unit for UT-DSAEK graft preparation helps in consistently obtaining UT-DSAEK grafts without compromising endothelial cell viability. [ABSTRACT FROM AUTHOR]

Introduction: Nearly 6.8 million people in India have vision less than 6/60 in at least one eye due to corneal diseases; of these, about a million had bilateral involvement. Purpose: To identify the challenges faced; the trends in collection, storage and utilisation of corneal tissues in an eye bank in north India. Materials and methods: The past records of Eye Bank linked to a tertiary hospital in northern India were analysed from November'1999 to October'2015 with respect to number of eye donations per year, donor demographics and utilisation of corneal tissues. Results: The number of donations during the first 6 years were 100, 279 in the next 5 years and 473 in the last 5 years. The mean donor age was 63.2 ± 19.5 years. The percentage of donors less than 30, 31–60 and more than 60 years was 10%, 28% and 62%. Forty-two percent donations were from the hospital. The average time between the death and enucleation was 4.74 ± 5.31 hours. The percentage of corneas used in the donor age groups less than 30, 31–60 and above 60 years was 61.9%, 61.6% and 53.8%, respectively. The usability rate of the corneas from home and hospital was 63.7% and 55.3%, respectively. Conclusions: The eye bank had a lukewarm response in the beginning, but gained momentum with time. The myths and beliefs prevalent in our society deter people from donating eyes freely. Each eye bank needs to individualise its problems and find solutions for adequate procurement and utilisation of tissue. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate possible differences in clinical outcomes between precut and surgeon-cut grafts for Descemet membrane endothelial keratoplasty (DMEK). Methods: 142 consecutive patients who underwent DMEK were included in the study. 44 patients received precut tissues, and 98 patients received surgeon-cut tissues. Precut grafts were allocated to the patient by the German Society for Tissue Transplantation if available. We compared the outcomes of both groups for changes in visual acuity, central corneal thickness, endothelial cell density, re-bubbling rate, and graft failure rate. Results: Patients who received precut tissues experienced similar increase in visual acuity (median change 0.4 logMAR) and decrease of corneal swelling (median change 132 μm) compared with those who received surgeon-cut tissues (median VA change 0.3 logMAR, p = 0.55, CCT change 118 μm, p = 0.63). There was no statistical difference in endothelial cell density (1436 vs. 1569 cells/mm2, p = 0.37), re-bubbling (32% vs. 35%, p = 0.85), and graft failure rate (5% vs. 1%, p = 0.23). No primary graft failure occurred in the group of precut grafts. Conclusion: Both methods lead to comparable results for visual acuity, corneal deswelling, endothelial cell density, and re-bubbling rate. A previously described higher graft failure rate for precut tissues could not be confirmed in our study. Thus, we do not see medical reasons against the use of precut tissues. There are several advantages of precut DMEK tissues over surgeon-cut tissues, especially the prevention of graft loss during preparation in the operating theater. [ABSTRACT FROM AUTHOR]

To report the current clinical applications and trends of scleral and amniotic membrane use in ophthalmology. Review of annual reports from the Catalan Transplant Organization (OCATT), on scleral patch and amniotic membrane eye indications in Catalonia region (Spain) over a 6-year period from 2013 to 2018. A total of 874 scleral and 1665 amniotic membranes patches were implanted, from January 2013 to December 2018. The most frequent indication over the 6-year period for scleral patch was glaucoma surgery (77.5%), eyelid reconstruction (5.2%) and corneal or scleral ulcer (5%). Regarding amniotic membrane, corneal ulcer (26.9%), conjunctival reconstruction (23.8%) and corneal epithelial defect (22.7%) were the most common indications. During the study period, an increasing trend was found on sclera patches for eyelid reconstruction (p = 0.0032) and amniotic membrane for inflammation management (p = 0.0198). Glaucoma surgery and corneal ulcers have represented the top indications for scleral patch and amniotic membrane use, over the period, respectively. A significant trend has also been found towards eyelid reconstruction using scleral patches and amniotic membrane for anterior segment inflammation management. This evolving scenario in tissue use for ocular surgery has to be taken into consideration, especially regarding eye banks facing current and futures changes in tissue preservation, storage and indications. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the microorganism detection and contamination rate of donor eyes. Study design: Retrospective study. Methods: In this retrospective study, we reviewed all donor cornea data collected from Kyoto Prefectural University of Medicine (KPUM) Eye Bank, Kyoto, Japan from April 2015 to June 2018, including microbiologic data obtained from conjunctival swabs and preservation medium and findings of postoperative infection from the medical records. Results: During the study period, 77 eyes from 44 deceased individuals (mean age at time of death: 75 ± 17.3 years [range, 30–102 years]) were donated to the KPUM Eye Bank after being harvested using standard safety precautions and disinfection procedures. In 49 of the 77 eyes (63.6%), the conjunctival-swab culture revealed microorganisms, with the 3 most commonly detected being methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-sensitive S aureus (MSSA), and methicillin-resistant S aureus (MRSA). The data revealed positive microorganism detection in only 4 (5.2%) of the 77 donor-cornea storage-medium cultures. Positive microorganism detection was found in all the age groups, with no statistical difference between the groups (P >.05). In the eyes enucleated ≥ 2.5 h postmortem, a higher positive microorganism detection occurred (P =.03). During the postoperative follow-up period, there was no record of corneal infection. Conclusions: The preenucleation conjunctival-swab-culture findings revealed that the rate of positive microorganism detection was similar for advanced-age and younger-age donors and that a shorter elapsed time from donor death to postmortem enucleation resulted in less donor-microorganism contamination. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the possibility to extend the storage of unused organ-cultured donor corneas. After 28 days of corneal culture in TISSUE-C (AL.CHI.MI.A. S.R.L., Italy) and 5-day storage in transport/deswelling medium CARRY-C (AL.CHI.MI.A. S.R.L., Italy), 25 corneas that were deemed suitable for transplantation were transferred in fresh TISSUE-C at 31 °C for additional 7 days and then in fresh CARRY-C at room temperature for 24 h. Tissues were assessed for endothelial cell density (ECD), endothelial mortality and morphology after the standard and the extended corneal storage. In addition, the effect of donor age < 85 years and ≥ 85 years on corneal characteristics was assessed. After the extended storage, 6 out of 25 tested corneas (24%) showed ECD values below the acceptance limit (< 2000 cells/mm2). 19 corneas (76%) were still suitable for transplantation and showed a 5.9% loss in ECD, which was not statistically significant (P = 0.0949) compared to standard storage period. The two donor age groups did not show statistically significant differences in any tested parameter, although a trend for lower ECD and higher mortality in Descemet's folds after standard storage was observed in the ≥ 85 age donor group. Thus, the attempt of the current study to provide new sight-restorative options for unused tissues and increasing the availability of corneas in case of shortage gave encouraging results. Although a higher vulnerability of corneas from very old donors could not be statistically demonstrated in the present study, higher sample size could be required for prolonging the shelf life of these tissues. [ABSTRACT FROM AUTHOR]

Currently, there are no specific guidelines in place to direct eye banks on how to deal with donated tissue from transgender individuals. This commentary will examine the history of corneal transplantation and the importance of the corneal tissue donor. In doing so, the donor selection criteria established by the Food and Drug Administration will be presented. Additionally, the history of blood donor deferral policies created for men who have sex with men and how those policies have changed over time will be explored. We provide an evidence-based framework for potential guidelines regarding the transgender population and eye tissue donation. [ABSTRACT FROM AUTHOR]

Our aim was to measure the endothelial quality of prestripped Descemet membrane endothelial keratoplasty (DMEK) 48 h after preparation in an eye bank with the Muraine technique and shipping in a distant center. Ten pairs of human corneas with similar eye bank endothelial cell density (ebECD) were stored in organ-culture (OC) for 25 days (20, 28) [median (10-90 percentiles)]. One cornea was then randomized to DMEK preparation using the Moria Muraine trephine, the other served as control. The grafts were left attached to the center of the cornea, immersed in the OC medium (without Dextran) and shipped to a distant center. After 48 h, the viable ECD (vECD) was assessed by image analysis after staining with Hoechst/Ethidium/Calcein-AM. In addition, immunostaining was performed on flat mounted tissues for structural (ZO-1, NCAM, CD166) and functional (Na+/K+ ATPase) proteins of ECs, and for collagen I. Just before stripping, ebECD was 2428 (2268-2669) cells/mm2 for DMEK and 2471 (2135-2714) for controls (P = 1). Forty-eight hours after stripping, vECD was 2057 (1829-2463) cells/mm2 for DMEK and 2119 (1496-2525) for controls (P = 0.508). The expression patterns of the 5 proteins were similar in ECs of both groups. Notably, the deep posterior folds observed in OC controls almost disappeared in prestripped DMEK due to the lack of a link between Descemet membrane and stroma. As a consequence of the elimination of mechanical stress in these zones, EC evenly covered the whole graft. In conclusion, DMEK prestripping with the Muraine technique and shipping away can be used safely by eye banks. [ABSTRACT FROM AUTHOR]

Surgical use of donor corneal tissue from victims of water submersion (drowning or submersion secondary to death) remains controversial due to limited evidence about the quality of these tissues. To assess the safety of donor corneal tissue from victims of water submersion, an investigation of eye banks' practice patterns and tissue outcomes was conducted. All 79 Eye Bank Association of America accredited eye banks were contacted for a phone interview of practices regarding tissue from victims of water submersion. A retrospective review of corneal tissues from 2014 to 2016 from a large eye bank network was performed to identify all donors submerged in water. Corneal epithelial integrity, endothelial cell density (ECD), rim cultures, and adverse events were analyzed for associations with water submersion characteristics. 49 eye banks (62% response) participated in the survey. 55% of these eye banks had specific, written protocol for tissue eligibility from donors submerged in water. With or without specific protocol, eye banks reported considering water type (84%) and length of time submerged (92%) to determine eligibility. 22% of eye banks reported medical director involvement when eligibility determination was unclear. 79 tissues from 40 donors who were submerged were identified in 2014-2016 eye bank data. No donor tissues had pre-processing corneal infiltrates, positive rim cultures, or adverse events post-keratoplasty. Corneal epithelial integrity and ECD were not associated with water type or length of time submerged. In conclusion, data from a large eye bank network showed no adverse events or outcomes, indicating these tissues may be safe. [ABSTRACT FROM AUTHOR]

The posterior side of the cornea is covered by the endothelial monolayer, which governs corneal transparency but cannot proliferate. Determination of endothelial cell density (ECD) is therefore the minimal and mandatory quality control in all eye banks. It avoids primary graft failures caused by endothelial insufficiency, and allows allocation of corneas to surgical techniques requiring different numbers of endothelial cells (ECs). Corneas stored in organ culture (17% of grafts worldwide), are characterized by heavy stromal swelling and numerous deep endothelial folds, up to 200 µm high. During microscopic en face observation, flat surfaces are thus exceptional and EC counting is biased by parallax errors, resulting in overestimated eye bank ECD (ebECD). We used a motorized transmitted light microscope to acquire Z-stacks of images every 10 µm, and processed them to reconstruct the 3D surface of the folded endothelium. This method (3D-ECD) takes into account the local point-by-point slope in order to correct ECD. On a set of 30 corneas, we compared 3D-ECD and ebECD determined on five identical zones at the center of the cornea. 3D reconstruction allowed us to visualize twice as many cells, and ebECD was 8.1 ± 4.5% (95%CI 6.4-9.7) higher than 3D-ECD, with 1744 ± 488 versus 1606 ± 473 cells/mm2. 3D counting makes it possible to increase cell sampling and to correct overestimation by the conventional en face counting still routinely performed in eye banks. [ABSTRACT FROM AUTHOR]

This study was conducted to analyze the profile and thickness of endothelial keratoplasty lenticules prepared from fresh donated whole eyes with Visante optical coherence tomography (V-OCT) compared to measurements obtained from ultrasound pachymetry (USP) at the Central Eye Bank of Iran. Microkeratome-assisted precut corneas were prepared for Descemet stripping automated endothelial keratoplasty by using standard eye bank protocol. Central posterior lenticule thickness (CPLT) on fresh whole eye, before excising corneoscleral disc and transferring to Optisol-GS, was measured by USP. V-OCT was used to measure central, paracentral, and midperipheral thicknesses of lenticules after transferring the tissue to Optisol-GS. Chi Square and Bonferroni tests were respectively used to uncover the differences between the USP and V-OCT measurements and also the thickness profile of lenticules. Postoperative reports for the entire transplanted lenticules were recorded. Accordingly, on evaluation of 312 enrolled precut corneas, CPLT measurements by V-OCT versus USP were statistically different (mean: 136 µm vs 165 µm, respectively; P = 0.008). Thickness profile of the posterior lenticules revealed increased thickness from the central to the peripheral parts of the cornea (mean increase of 16 µm at the pericentral and 64.2 µm at the peripheral locations, respectively); however, the increase in the thickness was relatively symmetrical. Postoperative reports of transplanted lenticules were unremarkable, since there were no posterior flap detachments. In essence, V-OCT measurements of microkeratome-assisted precut lenticules prepared from fresh donated whole eyes averaged 29 μm thinner than USP measurements and revealed a significant but symmetric increase of thickness towards the peripheral parts of the corneas. However, the variation in the thickness profile did not affect the attachment or the clarity of transplanted precut lenticlues. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Careful donor selection and implementation of tests of appropriate sensitivity and specificity are of paramount importance for minimizing the risk of transmitting infectious diseases from donors to corneal allograft recipients. Reported cases of viral transmission with corneal grafts are very unusual. Nevertheless potential virus transmission through the engraftment cannot be ruled out. According to European Guideline 2006/17/EC, screening for antibodies for Hepatitis B core antigen (anti HBc) is mandatory, and when this test is positive, some criteria must be established before using corneas. Despite the continuous progress in screening tests, donors carrying an occult hepatitis B infection (OBI) can cause transplant-transmitted hepatitis B. To date, Nucleic Acid Testing (NAT) is not an obligatory assay in corneal tissue setting neither in our country nor in the rest of European countries. Herein, we report three cornea donors that were rejected with the diagnosis of OBI through the testing of sensitive NAT and the serological profile of Hepatitis B virus. The aim of this report is to emphasize the need to include NAT in new reviews of EU Tissues and Cells Directives in order to increase level of security in tissue donation as well as not to reject a high number of donors with isolated profile of anti HBc in geographical areas with high prevalence of Hepatitis B, that could be rejected without a true criterion of Hepatitis B infection. [ABSTRACT FROM AUTHOR]

To investigate the de-orientation effect of DSAEK grafts by observing the cross patterns and polarization power of human donor corneas using a polarizing device (Lumaxis(®)). Forty human donor corneas were placed in small petri-plates with epithelial side facing up. Polarizing power (arbitrary unit) and crosses were monitored and recorded by the software. The tissue was marked at 'Superior' position to ensure that the base and the polarizer are in alignment with each other after the cut. The anterior lamellar cut was performed using microkeratome. The lenticule was placed back in the same position as marked to mimic the alignment. The tissue was further rotated by 45° ensuring that the base of the cornea and the polarizer were in alignment. The polarization power and 'crosses' were identified at each step. The average of forty corneas from pre-cut to post-45° angular change showed statistically significant difference (p < 0.05) in terms of polarizing power. The cross-shaped pattern deformed and lost the sharpness towards 45° angle. However, multiple variances in terms of 'cross-patterns' were observed throughout the study. Lumaxis(®) was able to determine the worst quality tissue in terms of polarization (no black zone and crosses). Despite the quality of cross pattern which can be used as an additional objective parameter to evaluate the optical properties of the corneal tissue, this preliminary study needs to be further justified in terms of clinical relevance whether polarization changes with oriented or de-oriented grafts have any effects and consequences on the visual acuity. [ABSTRACT FROM AUTHOR]

Specular microscopy can provide a non-invasive morphological analysis of the cornea endothelial cell layer. A variety of analysis programs are available to determine corneal endothelial quality. The flex-center endothelial analysis method (Konan Inc) is a newer technique including the outermost digitized cells and thus increases the number of cells for analysis. The aim of this study is to analyze whether the new flex-center method, increases the possibilities of corneal endothelium evaluation before implants. For this purpose 67 corneas were studied by both methods at the Eye Bank of the Tissue Establishment of Córdoba. Although we have found differences in the resulting of number of cells in the area analysed, no significant differences were found with respect to the endothelial cell count, coefficient of variation cell area, and the percentage of hexagonal cells recorded. Based on this data, both methods can be used satisfactorily in eye banking. [ABSTRACT FROM AUTHOR]

Ocular toxoplasmosis is the main cause of posterior uveitis worldwide frequently leading to vision loss. In Brazil, the seroprevalence of Toxoplasma gondii infection ranges from 50 to 80% depending of the region studied. The frequency of toxoplasmic retinal scar may reach 18% of the adults in the South of Brazil. Our goal was to determine the frequency of T. gondii DNA in retinas from eye banks from different regions in Brazil. A total of 162 eyes were obtained from eye banks in Manaus ( n = 60), Sao Paulo ( n = 60), Chapeco ( n = 26), and Joinville ( n = 16). The retinas were macroscopically analyzed and collected for DNA extraction. Real-time PCR (qPCR) was performed using the T. gondii B1 marker. By qPCR, a higher frequency of T. gondii DNA in the retinas from the eye bank of Joinville (25%) was found when compared to Manaus (5%). The retinas from Sao Paulo and Chapeco were qPCR negative. Clinical examination determined the retina lesions to be compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), Sao Paulo (6.7%), and Chapeco (15.4%). [ABSTRACT FROM AUTHOR]

The aim of this work was to analyze the magnitude of inherent errors associated with the fixed-frame counting method for corneal endothelial cell density (ECD) measurements. This technique is common among most eye banks worldwide. Three types of mosaics were used: regular and irregular tessellated mosaics (eight increasing densities ranging from 800 to 3,600 cells/mm by steps of 400 cells/mm) generated by a computer, and real mosaics (four specimens) obtained from human corneal endothelium flat mounted and stained with Alizarin red. On the three mosaics, the fixed-frame counting method was applied using a computer program. The ECD was calculated for 3,000 successive random positions from calibrated grids which area ranged from 50 × 50 to 300 × 300 μm (incremental steps of 25 μm). For each grid, the ECD was expressed either as a single count, a mean of five or a mean of 10 measures. The fixed-frame count was constantly associated with an inherent variability but repeatability increased with larger grid size and ECD. The mean calculated out of 10 measures was the most reliable, but still, we noted ±5 % of residual variability from the real ECD. The 100 × 100 μm grid manual counts, performed in many eye banks, should be abandoned and upgraded to at least 200 × 200 μm grid counts. Digital image analysis with a variable frame counting method would be the best alternative. [ABSTRACT FROM AUTHOR]

The aim of this study was to report the efficacy of adding chlorhexidine to the protocol for decontamination of human donor globes prior to excision of corneo-scleral rims for future keratoplasty procedures. In 2005, chlorhexidine was introduced by our eye bank as an additional step in the protocol for decontaminating human donor globes. After 5 years, we prospectively evaluated the number of contaminations. Out of 2,891 globes included in our study, 2,663 globes were processed, of which 36 (1.4%) were considered contaminated. Seventeen contaminations (0.6%) were detected by culturing limbal swabs, directly after decontamination, eight (0.3%) by visible discoloration of the culture medium carrying a corneo-scleral rim, and eleven (0.4%) after inoculation of the culture medium on blood agar plates. Importantly, after 4 weeks of incubation, none of the aerobic and anaerobic cultures taken from the secondary 'transport medium' (dextran containing medium used to transport corneal tissue to the transplantation centre) showed microbiological growth. In conclusion, the combined use of 0.02% chlorhexidine and 0.5% povidone-iodine may allow decontamination of donor globes to a level at which the risk of tissue contamination at the time of transplantation is minimized, while corneal viability is preserved. [ABSTRACT FROM AUTHOR]

To determine the incidence of early-onset (<30 days) and late-onset (>30 days) microbial keratitis after treatment of persistent corneal epithelial defects with amniotic membrane transplantation (AMT) utilizing tissue acquired from a commercial laboratory or prepared by the institutional eye bank. A retrospective, non-randomized, sequential, comparative study was performed for every patient with a persistent corneal epithelial defect who underwent primary AMT at KKESH between January 1, 2003 and June 30, 2004. A total of 142 AMT procedures were performed for persistent corneal epithelial defects during the study period. There were 72 cases using commercially prepared tissue and 70 cases using locally prepared tissue. The mean patient age was 50.3±25.6 years (range, 1–104 years). The mean follow up was 6.3±5.0 months (range, 1–21 months). There were no cases of early-onset microbial keratitis in cases in which either commercially acquired tissue or locally prepared tissue was used. Amniotic tissue prepared in a commercial laboratory or by properly qualified eye bank personnel may be used for AMT in eyes with persistent corneal epithelial defects with minimal risk of microbial keratitis in the first postoperative month. [ABSTRACT FROM AUTHOR]

One of the main clinical parameters expressing the health of a cornea is the cell density of its endothelium. This information is particularly important in an eye bank environment, where donor corneas are screened to assess their suitability as a human graft. Endothelium cell density is conventionally estimated by a long, tedious and error-prone manual counting procedure, performed by cornea experts on specimen images observed through an optical microscope. An alternative solution is proposed: a computer program that provides automatic estimation of cell density in donor corneas by analysing the spatial frequencies contained in the image. A circular band in the 2D discrete Fourier transform of the image is shown to contain the relevant information about the cell density. A system for extracting from this spatial frequency information an estimate of the cell density has been developed. A clinical evaluation of the proposed technique was performed on 18 corneas, where the densities provided by the proposed technique were compared with those manually obtained by two experts. The results showed an average percentage difference of 3% (maximum 19%), a value well within the measured inter-expert range of variability. The proposed automatic procedure confirmed its ability to estimate correctly corneal endothelium cell density. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. We have noticed that the incidence of positive serological tests of hepatitis C virus (HCV) among cornea donors in our eye bank is higher than expected. The purpose of this study was to determine the incidence of these positive findings and identify the contributory risk factors. Methods. All corneas procured between June 1993 and June 1997 were included in this retrospective study. In all cases a routine work-up, including serological testing of donors' sera and evaluation of the procured corneas, was performed prior to corneal transplantation. Donors found to be positive for HCV antibodies were compared to our general population of corneal donors, with respect to the demographic, serological and ophthalmological data obtained during the transplantation work-up. Results. All 851 corneas procured from 438 donors were included. Antibodies to HCV were found in 29 donors (6.6%). Following positive test results, 57 corneas (6.7%) were discarded. The time from donors' death to cornea procurement was significantly longer among HCV-positive patients than in the general donor population (12.3 vs. 9.3 h, p<0.0003). No other differences were detected between the two groups. Conclusion. Delay in harvesting of donated corneas may give rise to false positive HCV-antibodies test results, which may be partially responsible for the high rate of positive findings among cornea donors, with consequent tissue wastage. [ABSTRACT FROM AUTHOR]