Optimization and evaluation of oxygen-plasma-modified, aligned, poly (Є-caprolactone) and silk fibroin nanofibrous scaffold for corneal stromal regeneration.

The shortage of human donor corneas for transplantation necessitates the exploration of tissue engineering approaches to develop corneal substitutes. However, these substitutes must possess the necessary strength, transparency, and ability to regulate cell behaviour before they can be used in patients. In this study, we investigated the effectiveness of an oxygen plasma surface-modified poly-ε-caprolactone (PCL) combined with silk fibroin (SF) nanofibrous scaffold for corneal stromal regeneration. To fabricate the electrospun scaffolds, PCL and SF blends were used on a rotating mandrel. The optimization of the blend aimed to replicate the structural and functional properties of the human cornea, focusing on nanofibre alignment, mechanical characteristics, and in vitro cytocompatibility with human corneal stromal keratocytes. Surface modification of the scaffold resulted in improved transparency and enhanced cell interaction. Based on the evaluation, a composite nanofibrous scaffold with a 1:1 blend of PCL and SF was selected for a more comprehensive analysis. The biological response of keratocytes to the scaffold was assessed through cellular adhesion, proliferation, cytoskeletal organization, gene expression, and immunocytochemical staining. The scaffold facilitated the adhesion of corneal stromal cells, supporting cell proliferation, maintaining normal cytoskeletal organization, and promoting increased expression of genes associated with healthy corneal stromal keratocytes. These findings highlight the potential of a surface-modified PCL/SF blend (1:1) as a promising scaffolding material for corneal stromal regeneration. The developed scaffold not only demonstrated favourable biological interactions with corneal stromal cells but also exhibited characteristics aligned with the requirements for successful corneal tissue engineering. Further research and refinement of these constructs could lead to significant advancements in addressing the shortage of corneas for transplantation, ultimately improving the treatment outcomes for patients in need.

The effect of prior long-term recellularization with keratocytes of decellularized porcine corneas implanted in a rabbit anterior lamellar keratoplasty model.

Decellularized porcine corneal scaffolds are a potential alternative to human cornea for keratoplasty. Although clinical trials have reported promising results, there can be corneal haze or scar tissue. Here, we examined if recellularizing the scaffolds with human keratocytes would result in a better outcome. Scaffolds were prepared that retained little DNA (14.89 ± 5.56 ng/mg) and demonstrated a lack of cytotoxicity by in vitro. The scaffolds were recellularized using human corneal stromal cells and cultured for between 14 in serum-supplemented media followed by a further 14 days in either serum free or serum-supplemented media. All groups showed full-depth cell penetration after 14 days. When serum was present, staining for ALDH3A1 remained weak but after serum-free culture, staining was brighter and the keratocytes adopted a native dendritic morphology with an increase (p < 0.05) of keratocan, decorin, lumican and CD34 gene expression. A rabbit anterior lamellar keratoplasty model was used to compare implanting a 250 µm thick decellularized lenticule against one that had been recellularized with human stromal cells after serum-free culture. In both groups, host rabbit epithelium covered the implants, but transparency was not restored after 3 months. Post-mortem histology showed under the epithelium, a less-compact collagen layer, which appeared to be a regenerating zone with some α-SMA staining, indicating fibrotic cells. In the posterior scaffold, ALDH1A1 staining was present in all the acellular scaffold, but in only one of the recellularized lenticules. Since there was little difference between acellular and cell-seeded scaffolds in our in vivo study, future scaffold development should use acellular controls to determine if cells are necessary.

Multilayered Fabrication Assembly Technique to Engineer a Corneal Stromal Equivalent.

Tissue engineering has emerged as a strategy to combat the donor shortage of human corneas for transplantation. Synthetic corneal substitutes are currently unable to support the normal phenotype of human cells and so decellularized animal corneas have been deployed to more closely provide the topographical and biochemical cues to promote cell attachment and function. Although full thickness decellularized corneas can support corneal cells, the cells are slow to populate the scaffold and density declines from the surface. To avoid these problems, this protocol describes the stacking of alternate layers of decellularized porcine corneal sheets and cell-laden collagen hydrogel to produce a corneal construct. The sheets are obtained by cryosectioning porcine corneas, decellularizing them with detergents and nucleases and finally air drying for storage and ease of manufacture. Corneal stromal cells are then encapsulated in a collagen type I solution and cast between these sheets. This protocol presents a rapid method to ensure high cellularity throughout the construct using tissue-derived materials alone. Graphic abstract: Overview of main process to obtain corneal stromal equivalents.

Silk fibroin safety in the eye: a review that highlights a concern.

The biomedical use of silk as a suture dates back to antiquity. Fibroin is the structural element that determines the strength of silk and here we consider the safety of fibroin in its role in ophthalmology. The high mechanical strength of silk meant sufficiently thin threads could be made for eye microsurgery, but such usage was all but superseded by synthetic polymer sutures, primarily because silk in its entirety was more inflammatory. Significant immunological response can normally be avoided by careful manufacturing to provide high purity fibroin, and it has been utilised in this form for tissue engineering an array of fibre and film substrata deployed in research with cells of the eye. Films of fibroin can also be made transparent, which is a required property in the visual pathway. Transparent layers of corneal epithelial, stromal and endothelial cells have all been demonstrated with maintenance of phenotype, as have constructs supporting retinal cells. Fibroin has a lack of demonstrable infectious agent transfer, an ability to be sterilised and prepared with minimal contamination, long-term predictable degradation and low direct cytotoxicity. However, there remains a known ability to be involved in amyloid formation and potential amyloidosis which, without further examination, is enough to currently question whether fibroin should be employed in the eye given its innervation into the brain.

The Use of Animal Models to Assess Engineered Corneal Tissue.

Tissue-engineered corneal constructs offer the potential of readily available corneal substitutes for transplantation. As with all medical devices and implants, these constructs require rigorous safety assessments, combined with well-described analyses of the implant's physical and biological characteristics. Although the constructs are developed in vitro, such studies are currently unable to fully emulate the complex biomechanical and biochemical conditions within living tissue, as well as the interplay between this environment and immunological factors. For these reasons, animal models remain essential to characterize such interactions. They form a stage where corneal implants can be tested for utility and survival in a living location to assess their ability to provide vision and avoid adverse event. Here, we examine the surgical considerations of animal models and we describe how the rabbit can be used for this purpose. This animal has been the routine model for ophthalmological studies and we set out methods to implant corneal constructs with this species.

Engineering a Corneal Stromal Equivalent Using a Novel Multilayered Fabrication Assembly Technique.

To overcome the serious shortage of donor corneas for transplantation, alternatives based on tissue engineering need to be developed. Decellularized corneas are one potential alternative, but their densely packed collagen architecture inhibits recellularization in vitro. Therefore, a new rapid method of recellularizing these constructs to ensure high cellularity throughout the collagen scaffold is needed. In this study, we developed a novel method for fabricating corneal constructs by using decellularized porcine corneal sheets assembled using a bottom-up approach by layering multiple sheets between cell-laden collagen I hydrogel. Corneal lenticules were cut from porcine corneas by cryosectioning, then decellularized with detergents and air-dried for storage as sheets. Human corneal stromal cells were encapsulated in collagen I hydrogel and cast between the dried sheets. Constructs were cultured in serum-free medium supplemented with ascorbic acid and insulin for 2 weeks. Epithelial cells were then seeded on the surface and cultured for an additional week. Transparency, cell viability, and phenotype were analyzed by qPCR, histology, and immunofluorescence. Constructs without epithelial cells were sutured onto an ex vivo porcine cornea and cultured for 1 week. Lenticules were successfully decellularized, achieving dsDNA values of 13 ± 1.2 ng/mg dry tissue, and were more resistant to degradation than the collagen I hydrogels. Constructs maintained high cell viability with a keratocyte-like phenotype with upregulation of keratocan, decorin, lumican, collagen I, ALDH3A1, and CD34 and the corneal epithelial cells stratified with a cobblestone morphology. The construct was amenable to surgical handling and no tearing occurred during suturing. After 7 days ex vivo, constructs were covered by a neoepithelium from the host porcine cells and integration into the host stroma was observed. This study describes a novel approach toward fabricating anterior corneal substitutes in a simple and rapid manner, obtaining mature and suturable constructs using only tissue-derived materials.

Deformation velocity imaging using optical coherence tomography and its applications to the cornea.

Optical coherence tomography (OCT) can monitor human donor corneas non-invasively during the de-swelling process following storage for corneal transplantation, but currently only resultant thickness as a function of time is extracted. To visualize and quantify the mechanism of de-swelling, we present a method exploiting the nanometer sensitivity of the Fourier phase in OCT data to image deformation velocities. The technique was demonstrated by non-invasively showing during de-swelling that osmotic flow through an intact epithelium is negligible and removing the endothelium approximately doubled the initial flow at that interface. The increased functional data further enabled the validation of a mathematical model of the cornea. Included is an efficient method of measuring high temporal resolution (1 minute demonstrated) corneal thickness, using automated collection and semi-automated graph search segmentation. These methods expand OCT capabilities to measure volume change processes for tissues and materials.

Predictive value of dysplasia grading and DNA ploidy in malignant transformation of oral potentially malignant disorders.

Dysplasia grading is widely used to assess risk of transformation in oral potentially malignant disorders despite limited data on predictive value. DNA ploidy analysis has been proposed as an alternative. This study examines the prognostic value for both tests used in a routine diagnostic setting to inform clinical management. A retrospective study of conventional dysplasia grading was conducted on 1,401 patients. DNA ploidy analysis was conducted on a subset of 273 patients and results correlated with clinical information, pathologic diagnosis, and outcome over 5 to 15 years. Malignant transformation occurred in 32 of 273 patients (12%) and, of these, 20 (63%) of preexisting index lesions were aneuploid. Of 241 patients not developing carcinoma, only 39 (16%) of index lesions were aneuploid. Epithelial dysplasia correlated with DNA ploidy status (P < 0.001). The overall positive predictive value for malignant transformation by DNA aneuploidy was 38.5% (sensitivity 65.2% and specificity 75%) and by severe dysplasia grade 39.5% (sensitivity 30% and specificity 98%). DNA diploid and tetraploid status had negative predictive value of 90% to 96%. Combining DNA ploidy analysis with dysplasia grading gives a higher predictive value than either technique alone. Each of three traditional dysplasia grades predicts a significantly different risk of carcinoma development and time to transformation. DNA ploidy analysis had equivalent predictive value and also detected additional risk lesions in the absence of dysplasia.

Functional morphology of the fin rays of teleost fishes.

Ray-finned fishes are notable for having flexible fins that allow for the control of fluid forces. A number of studies have addressed the muscular control, kinematics, and hydrodynamics of flexible fins, but little work has investigated just how flexible ray-finned fish fin rays are, and how flexibility affects their response to environmental perturbations. Analysis of pectoral fin rays of bluegill sunfish showed that the more proximal portion of the fin ray is unsegmented while the distal 60% of the fin ray is segmented. We examined the range of motion and curvatures of the pectoral fin rays of bluegill sunfish during steady swimming, turning maneuvers, and hovering behaviors and during a vortex perturbation impacting the fin during the fin beat. Under normal swimming conditions, curvatures did not exceed 0.029 mm(-1) in the proximal, unsegmented portion of the fin ray and 0.065 mm(-1) in the distal, segmented portion of the fin ray. When perturbed by a vortex jet traveling at approximately 1 ms(-1) (67 ± 2.3 mN s.e. of force at impact), the fin ray underwent a maximum curvature of 9.38 mm(-1) . Buckling of the fin ray was constrained to the area of impact and did not disrupt the motion of the pectoral fin during swimming. Flexural stiffness of the fin ray was calculated to be 565 × 10(-6) Nm2 . In computational fluid dynamic simulations of the fin-vortex interaction, very flexible fin rays showed a combination of attraction and repulsion to impacting vortex dipoles. Due to their small bending rigidity (or flexural stiffness), impacting vortices transferred little force to the fin ray. Conversely, stiffer fin rays experienced rapid small-amplitude oscillations from vortex impacts, with large impact forces all along the length of the fin ray. Segmentation is a key design feature of ray-finned fish fin rays, and may serve as a means of making a flexible fin ray out of a rigid material (bone). This flexibility may offer intrinsic damping of environmental fluid perturbations encountered by swimming fish.

Standard terminology and labeling of ocular tissue for transplantation.

PURPOSE: To develop an internationally agreed terminology for describing ocular tissue grafts to improve the accuracy and reliability of information transfer, to enhance tissue traceability, and to facilitate the gathering of comparative global activity data, including denominator data for use in biovigilance analyses. METHODS: ICCBBA, the international standards organization for terminology, coding, and labeling of blood, cells, and tissues, approached the major Eye Bank Associations to form an expert advisory group. The group met by regular conference calls to develop a standard terminology, which was released for public consultation and amended accordingly. RESULTS: The terminology uses broad definitions (Classes) with modifying characteristics (Attributes) to define each ocular tissue product. The terminology may be used within the ISBT 128 system to label tissue products with standardized bar codes enabling the electronic capture of critical data in the collection, processing, and distribution of tissues. Guidance on coding and labeling has also been developed. CONCLUSIONS: The development of a standard terminology for ocular tissue marks an important step for improving traceability and reducing the risk of mistakes due to transcription errors. ISBT 128 computer codes have been assigned and may now be used to label ocular tissues. Eye banks are encouraged to adopt this standard terminology and move toward full implementation of ISBT 128 nomenclature, coding, and labeling.

Evaluation of Eph receptor and ephrin expression within the human cornea and limbus.

Eph receptor tyrosine kinases and their ligands, the ephrins, regulate the development and maintenance of multiple organs but little is known about their potential role within the cornea. The purpose of this study was to perform a thorough investigation of Eph/ephrin expression within the human cornea including the limbal stem cell niche. Initially, immunohistochemistry was performed on human donor eyes to determine the spatial distribution of Eph receptors and ephrins in the cornea and limbus. Patterns of Eph/ephrin gene expression in (1) immortalised human corneal endothelial (B4G12) or corneal epithelial (HCE-T) cell lines, and (2) primary cultures of epithelial or stromal cells established from the corneal limbus of cadaveric eye tissue were then assessed by reverse transcription (RT) PCR. Limbal epithelial or stromal cells from primary cultures were also assessed for evidence of Eph/ephrin-reactivity by immunofluorescence. Immunoreactivity for ephrinA1 and EphB4 was detected in the corneal endothelium of donor eyes. EphB4 was also consistently detected in the limbal and corneal epithelium and in cells located in the stroma of the peripheral cornea. Expression of multiple Eph/ephrin genes was detected in immortalised corneal epithelial and endothelial cell lines. Evidence of Eph/ephrin gene expression was also demonstrated in primary cultures of human limbal stromal (EphB4, B6; ephrinA5) and epithelial cells (EphA1, A2; ephrinA5, B2) using both RT-PCR and immunofluorescence. The expression of Eph receptors and ephrins within the human cornea and limbus is much wider than previously appreciated and suggests multiple potential roles for these molecules in the maintenance of normal corneal architecture.

Effect of the sterilization method on the properties of Bombyx mori silk fibroin films.

We have compared the effects of different sterilization techniques on the properties of Bombyx mori silk fibroin thin films with the view to subsequent use for corneal tissue engineering. The transparency, tensile properties, corneal epithelial cell attachment and degradation of the films were used to evaluate the suitability of certain sterilization techniques including gamma-irradiation (in air or nitrogen), steam treatment and immersion in aqueous ethanol. The investigations showed that gamma-irradiation, performed either in air or in a nitrogen atmosphere, did not significantly alter the properties of films. The films sterilized by gamma-irradiation or by immersion in ethanol had a transparency greater than 98% and tensile properties comparable to human cornea and amniotic membrane, the materials of choice in the reconstruction of ocular surface. Although steam-sterilization produced stronger, stiffer films, they were less transparent, and cell attachment was affected by the variable topography of these films. It was concluded that gamma-irradiation should be considered to be the most suitable method for the sterilization of silk fibroin films, however, the treatment with ethanol is also an acceptable method.

Using patients' experiences to identify priorities for quality improvement in breast cancer care: patient narratives, surveys or both?

BACKGROUND: Patients' experiences have become central to assessing the performance of healthcare systems worldwide and are increasingly being used to inform quality improvement processes. This paper explores the relative value of surveys and detailed patient narratives in identifying priorities for improving breast cancer services as part of a quality improvement process. METHODS: One dataset was collected using a narrative interview approach, (n = 13) and the other using a postal survey (n = 82). Datasets were analyzed separately and then compared to determine whether similar priorities for improving patient experiences were identified. RESULTS: There were both similarities and differences in the improvement priorities arising from each approach. Day surgery was specifically identified as a priority in the narrative dataset but included in the survey recommendations only as part of a broader priority around improving inpatient experience. Both datasets identified appointment systems, patients spending enough time with staff, information about treatment and side effects and more information at the end of treatment as priorities. The specific priorities identified by the narrative interviews commonly related to 'relational' aspects of patient experience. Those identified by the survey typically related to more 'functional' aspects and were not always sufficiently detailed to identify specific improvement actions. CONCLUSIONS: Our analysis suggests that whilst local survey data may act as a screening tool to identify potential problems within the breast cancer service, they do not always provide sufficient detail of what to do to improve that service. These findings may have wider applicability in other services. We recommend using an initial preliminary survey, with better use of survey open comments, followed by an in-depth qualitative analysis to help deliver improvements to relational and functional aspects of patient experience.

Human epidermal growth factor receptor 2-positive breast cancer relapsing post-adjuvant trastuzumab: pattern of recurrence, treatment and outcome.

BACKGROUND: The purpose of this study is to evaluate the response to and benefit of first-line metastatic treatment (including re-exposure to trastuzumab) for patients relapsing after exposure to adjuvant trastuzumab (AT). PATIENTS AND METHODS: All HER2-positive breast cancer cases relapsing after exposure to AT at our institutions were identified. Clinico-pathologic details, pattern of relapse, and treatment in the metastatic setting were documented. Response to treatment and outcome were assessed. RESULTS: Twenty-nine relapses were recorded. The median time to relapse was 18.4 months from diagnosis, and 8.7 months from AT initiation. At a median time of observation of 9.9 months, 18 patients had progressed on first-line therapy. The median time-to-progression (TTP) was 8.6 months. Fifteen patients received trastuzumab as first-line treatment, with no statistical difference in TTP between this group and those not re-exposed to trastuzumab. TTP was not statistically different between those relapsing on or after AT. Overall survival was longer for those who relapsed after completion of 1 year of AT as well as those who received further trastuzumab at relapse; however, this did not reach statistical significance. CONCLUSION: Overall survival was longer in patients who relapse after completion of AT and who received further trastuzumab at progression.

Human corneal endothelial cell growth on a silk fibroin membrane.

Tissue engineering of the cornea could overcome shortages of donor corneas for transplantation and improve quality. Our aim was to grow an endothelial layer on a substratum suitable for transplant. Silkworm (Bombyx mori) fibroin was prepared as 5 µm thick transparent membranes. The B4G12 cell line was used to assess attachment and growth of human corneal endothelial cells on fibroin and compare this with a reference substratum of tissue-culture plastic. To see if cell attachment and proliferation could be improved, we assessed coatings of collagen IV, FNC Coating Mix(®) and a chondroitin sulphate-laminin mixture. All the coatings improved the final mean cell count, but consistently higher cell densities were achieved on a tissue-culture plastic rather than fibroin substratum. Collagen-coated substrata were the best of both groups and collagen-coated fibroin was comparable to uncoated tissue-culture plastic. Only fibroin with collagen coating achieved cell confluency. Primary human corneal endothelial cells were then grown using a sphere-forming technique and when seeded onto collagen-coated fibroin they grew to confluency with polygonal morphology. We report the first successful growth of primary human corneal endothelial cells on coated fibroin as a step in evaluating fibroin as a substratum for the transplantation of tissue-constructs for endothelial keratoplasty.

Does place of death from cancer vary between ethnic groups in South East England?

There is growing evidence that the palliative care needs of certain people, such as those from minority ethnic groups, are not being met. The aim of this study was to investigate whether place of death from cancer differs between ethnic groups. A total of 101,516 patients resident in South East England and who died from lung, colorectal, breast or prostate cancer between 1998 and 2006 were extracted from the Thames Cancer Registry database. Ethnicity data were available for 68,804 patients (68%). The odds ratios (ORs) of death from cancer in a hospice, at home or in hospital were calculated. The results were adjusted for age at death, deprivation, cancer network of residence and time between diagnosis and death. Following adjustment, death in a hospice was significantly less likely for Pakistani patients (OR=0.47 95% CI [0.30-0.74]), Indian patients (0.68 [0.55-0.84]) and Bangladeshi patients (0.33 [0.19-0.56]). Death at home was significantly less likely in Black African patients (0.48 [0.36-0.65]), Black Caribbean patients (0.78 [0.67-0.90]) and Chinese patients (0.46 [0.28-0.76]). Pakistani, Indian, Bangladeshi, Black African, Black Caribbean and Chinese patients were all significantly more likely than White patients to die in hospital. The results were not substantially altered by recoding the unknown ethnicity group to White or using multiple imputation to assign those with a missing ethnicity an ethnic group. Place of death varies between ethnic groups. This may reflect differences in preferences for place of death or barriers to accessing specialist care in different settings. More detailed prospective qualitative studies are urgently required to determine reasons for this variation.

Silk fibroin in ocular tissue reconstruction.

The silk structural protein fibroin displays potential for use in tissue engineering. We present here our opinion of its value as a biomaterial for reconstructing tissues of clinical significance within the human eye. We review the strengths and weaknesses of using fibroin in those parts of the eye that we believe are most amenable to cellular reconstruction, namely the corneoscleral limbus, corneal stroma, corneal endothelium and outer blood-retinal barrier (Ruysch's complex). In these areas we find that by employing the range of manufacturing products afforded by fibroin, relevant structural assemblies can be made for cells expanded ex vivo. Significant questions now need to be answered concerning the effect of this biomaterial on the phenotype of key cell types and the biocompatibility of fibroin within the eye. We conclude that fibroin's strength, structural versatility and potential for modification, combined with the relative simplicity of associated manufacturing processes, make fibroin a worthy candidate for further exploration.

The effect of fin ray flexural rigidity on the propulsive forces generated by a biorobotic fish pectoral fin.

A biorobotic pectoral fin was developed and used to study how the flexural rigidities of fin rays within a highly deformable fish fin affect the fin's propulsive forces. The design of the biorobotic fin was based on a detailed analysis of the pectoral fin of the bluegill sunfish (Lepomis macrochirus). The biorobotic fin was made to execute the kinematics used by the biological fin during steady swimming, and to have structural properties that modeled those of the biological fin. This resulted in an engineered fin that had a similar interaction with the water as the biological fin and that created close approximations of the three-dimensional motions, flows, and forces produced by the sunfish during low speed, steady swimming. Experimental trials were conducted during which biorobotic fins of seven different stiffness configurations were flapped at frequencies from 0.5 to 2.0 Hz in flows with velocities that ranged from 0 to 270 mm s(-1). During these trials, thrust and lift forces were measured, kinematics were recorded in three dimensions, and digital particle image velocimetry was used to evaluate flow hydrodynamics. The results of the trials revealed that slight changes to the fin's mechanical properties or to the operating conditions can have significant impact on the direction, magnitude and time course of the propulsive forces. In general, the magnitude of the 2-D (thrust and lift) propulsive force scaled with fin ray stiffness, and increased as the fin's flapping speed increased or as the velocity of the flow decreased.

Reporting cancer patients' experiences of care for quality improvement: analysis of 2000 and 2004 survey results for South East England.

BACKGROUND: National surveys of patients' experiences of English cancer services found improvements between 2000 and 2004, particularly in the areas of information, communication and trust in professionals. OBJECTIVES: We assessed the potential such surveys might have to stimulate service improvements by comparing their inclusion criteria, sampling and timing and by investigating how representative they were of patients registered with cancer in South East England. Where hospital trusts had data from 50 patients with the same cancer, we determined whether national improvements in six key areas held at hospital trust level. DESIGN: Data were extracted from the two national surveys and from the Thames Cancer Registry. RESULTS: The 2000 survey achieved a higher response rate, included a larger number of hospital trusts, and a wider range of cancer sites, but a lower proportion with lung cancer. Each survey sampled patients at different points following diagnosis, with a year elapsing between data collection and reporting. Compared with cancer registry data, breast cancer patients appeared most well-represented. Only three hospital trusts had sufficiently large samples to allow comparison over time. We found no change in experience in three of the key areas, but a significant decline from previously high scores in two. CONCLUSION: To provide information useful for quality improvement future surveys will need to sample larger numbers of patients from most hospital trusts, including patients with less common cancers or receiving palliative care. Surveys should also sample patients at a consistent time after diagnosis and feedback results more rapidly to services.

Potential effect of excluding variant Creutzfeldt-Jakob disease on the eye donor pool in Australia.

PURPOSE: To quantitate the likely effect on the available eye donor pool by excluding potential donors who may have had exposure to variant Creutzfeldt-Jakob disease by virtue of spending time in countries where bovine spongiform encephalopathy (BSE) is endemic. METHODS: A telephone survey by systematic sampling from the Brisbane phone directory was undertaken to ascertain the number of potential donors who had resided in the United Kingdom and in other countries. RESULTS: Between 19% of potential donors would have had to have been excluded by virtue of residing in the United Kingdom for >6 months between 1980 and 1996 and 29% for those who had traveled to any other country in which BSE was identified. CONCLUSIONS: This study suggests that adopting an eye bank policy of excluding donors potentially exposed to BSE would have a significant effect on donor numbers. Health departments and eye banks will need to weigh the small additional protection from such policy decisions against the likely effect on corneal tissue supply.