Search

Federated learning is becoming increasingly more popular as the concern of privacy breaches rises across disciplines including the biological and biomedical fields. The main idea is to train models locally on each server using data that are only available to that server and aggregate the model (not data) information at the global level. While federated learning has made significant advancements for machine learning methods such as deep neural networks, to the best of our knowledge, its development in sparse Bayesian models is still lacking. Sparse Bayesian models are highly interpretable with natural uncertain quantification, a desirable property for many scientific problems. However, without a federated learning algorithm, their applicability to sensitive biological/biomedical data from multiple sources is limited. Therefore, to fill this gap in the literature, we propose a new Bayesian federated learning framework that is capable of pooling information from different data sources without breaching privacy. The proposed method is conceptually simple to understand and implement, accommodates sampling heterogeneity (i.e., non-iid observations) across data sources, and allows for principled uncertainty quantification. We illustrate the proposed framework with three concrete sparse Bayesian models, namely, sparse regression, Markov random field, and directed graphical models. The application of these three models is demonstrated through three real data examples including a multi-hospital COVID-19 study, breast cancer protein-protein interaction networks, and gene regulatory networks.

Liver macrophage-mediated inflammation contributes to the pathogenesis of the non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Odd skipped-related 1 (Osr1) is a putative transcription factor previously reported to be involved in NASH progression; however, the underlying mechanisms remain unknown. The current study focused on the role of Osr1 in macrophage polarization and metabolism and its associated functions in the inflammation-induced pathogenesis of NASH.OSR1/Osr1 expression patterns were compared in normal and NASH patients and mouse livers. NASH was established and compared between hepatocyte-specific Osr1 knockout (Osr1Osr1 was expressed in both hepatocytes and macrophages and exhibited different expression patterns in NASH. In NAFLD and NASH murine models, deleting Osr1 in myeloid cells (Osr1Myeloid Osr1 mediates liver immune homeostasis, and disrupting Osr1 aggravates the progression of NAFLD/NASH.

Funding: This research was supported by a grant from TENOVUS Scotland, a national charity supporting medical research and involved in the improvement of healthcare within Scotland, UK. Introduction: Substance misuse is not uncommonly recognized in people with epilepsy (PWE). Mortality is significantly greater in those with comorbid substance misuse, but it remains unclear whether epilepsy care and management contribute to this. This cohort study aimed to compare the rates of mortality in PWE receiving opiate replacement therapy (ORT) and PWE alone, as well as evaluate their medication adherence, levels of engagement with epilepsy services as currently delivered, and utilization of unscheduled hospital care. Material and methods: A 5-year historical cohort for PWE was identified and manually validated using electronic patient records registered with NHS Tayside. Overall incidence rates for mortality and contact with emergency health care services were calculated for PWE receiving ORT and PWE alone. Engagement with outpatient epilepsy services was also noted. Adherence to antiepileptic drugs (AEDs) was expressed in terms of medication possession ratio (MPR). Results: Of the 1297 PWE attending a tertiary care epilepsy service, 68 (5.3%) PWE were receiving ORT. The mortality rate was significantly greater in PWE on ORT in comparison to PWE only (7.4% vs 1.7 %; P

This chapter differs from the others in that it does not provide new information, but rather tries to provide a framework within which to think about local strategy development. It argues that a strategic approach is an asset to an area and that flexibility and local adaptation are essential for success. Taken with the other material available on drug misuse - local and national reports, information from services and from drug users and their families, academic journals, newspaper reports and other textbooks - the volume of information and advice for people developing local strategies is overwhelming. Local strategy development needs to consider the number of people likely to benefit from an initiative, the gain expected from the intervention and the cost of the change compared to alternative uses of the same resource. Strategic plans are often regarded as huge, distant creations, which are as difficult to slow down, stop and change direction as are oil tankers lumbering across the Atlantic.

This book provides a comprehensive review of information and interventions available in drug misuse to inform local drug policies. In keeping with the policy documents in both Scotland and England, the volume will cover the breadth of possible intervention, rather than health care alone. Each chapter dealing with interventions reviews the evidence of effectiveness of competing methods and uses a standard method to indicate the strength of evidence, thereby making comparisons very easy. Although there are specialist textbooks on all aspects of addiction this is the first book to bring together information in the framework used in the new policy documents in the UK.

The history of opiate treatment in the United Kingdom (UK) since the early 1980s is a rich source of learning about the benefits and pitfalls of drug treatment policy. We present five possible lessons to be learnt about how factors outside the clinic, including government, charities and researchers can influence treatment and outcomes. First, do not let a crisis go to waste. The philosophical shift from abstinence to harm reduction in the 1980s, in response to an HIV outbreak in injecting users, facilitated expansion in addiction services and made a harm reduction approach more acceptable. Second, studies of drug-related deaths can lead to advances in care. By elucidating the pattern of mortality, and designing interventions to address the causes, researchers have improved patient safety in certain contexts, though significant investment in Scotland has not arrested rising mortality. Third, collection of longitudinal data and its use to inform clinical guidelines, as pursued from the mid-1990s, can form an enduring evidence base and shape policy, sometimes in unintended ways. Fourth, beware of the presentation of harm reduction and recovery as in conflict. At the least, this reduces patient choice, and at worst, it has caused some services to be redesigned in a manner that jeopardises patient safety. Fifth, the relationship between the third and state sectors must be carefully nurtured. In the UK, early collaboration has been replaced by competition, driven by changes in funding, to the detriment of service provision.

Excited random walks (ERWs) are a self-interacting non-Markovian random walk in which the future behavior of the walk is influenced by the number of times the walk has previously visited its current site. We study the speed of the walk, defined as $V = \lim_{n \rightarrow \infty} \frac{X_n}{n}$ where $X_n$ is the state of the walk at time $n$. While results exist that indicate when the speed is non-zero, there exists no explicit formula for the speed. It is difficult to solve for the speed directly due to complex dependencies in the walk since the next step of the walker depends on how many times the walker has reached the current site. We derive the first non-trivial upper and lower bounds for the speed of the walk. In certain cases these upper and lower bounds are remarkably close together., Comment: 13 pages, 2 figures

Drug related deaths (DRDs) have been increasing in Scotland over at least the past decade. This study aimed to describe the characteristics (gender, age, ICD10 cause of death), toxicology and circumstances of all Scotland's DRDs in 2003 to help inform a national overdose prevention strategy. Coronial files for 300/317 (95%) DRDs registered with the General Register Office for Scotland (GROS) in 2003 were examined retrospectively (in 2004). Characteristics: 241/300 (80%) were male. Mean age at death was 32.8 years (SE 0.63, range 16–82). Route of administration was injecting for 137/268 (51%) who were classifiable. Classified injectors were more likely to be male (91%: 124/137) and younger (mean age of 32 years) than those whose death was by a non-injecting route (male: 87/131 (66%) and mean age of 35 years). Twenty-five to forty-four year olds made up 108/137 DRDs by injecting (79%), but only 62/131 (47%) by non-injecting routes. Cases of intentional self-poisoning (injectors 1; non-injecting 34) and unde...

This study aims to answer the question of what can architects and electronic and computer engineers offer to people with vision impairment? This research project is being undertaken jointly at the Faculty of Architecture, Landscape and Visual Arts—University of Western Australia and the Department of Electrical and Computer Engineering at Curtin University of Technology. The study demonstrates the processes of architects and electronic computer engineers' work with vision impaired people. This research will examine how architects and electronic computer engineers meet the needs of the vision impaired within the area of learning environments. By being involved in a project for the creation of a revolutionary new building at the Association for the Blind of Western Australia and working under the supervision of an architect who has had over thirty years experience in the areas of aging and sensory loss, will assist in the study of how to meet the needs of vision impaired people in their building environments. Participation in the Cisco Network Academy Program with the vision impaired students at Curtin University will be vital and explain the different ways of learning and the interaction of vision impaired students with their educational technology. This will become a good source to experts in a variety of fields, who work with the vision impaired so as to be able to study their reaction to new technology.

Buprenorphine is prescribed as a treatment for opioid dependence (Barnett et al, 2001; Lintzeris et al, 2002). Methadone substitute prescribing is the primary maintenance treatment in Britain and is well established (Ward, 1997). Despite the advantages of methadone maintenance there are associated disadvantages, including potential death following overdose, the inconvenience of daily dosing, the risk of the drug being used by others and stigma (Walsh, 1994).

Neuropathic pain affects up to 8% of the population,1 causing significant distress and morbidity. Good evidence-based treatment is available,2 so early diagnosis is important. Recent publicity and guidelines, and increasing prevalences of age-related causes of neuropathic pain (including postherpetic neuralgia and diabetic neuropathy), have led to increasing rates of diagnosis and treatment in primary care. Gabapentin is one of the recommended mainstays of evidence-based treatment.3 Unfortunately, our clinical experience suggests that gabapentin is now prevalent as a drug of abuse. The drug’s effects vary with the user, dosage, …

The aim of this study was to analyse the nature and extent of data extracted from case files of deceased individuals in contact with services 6 months prior to drug deaths in Scotland during 2003. A cross-sectional descriptive analysis of 317 case notes of 237 individuals who had drug-related deaths was undertaken, using a data linkage process. All contacts made with services in the 6 months prior to death were identified. Information on clinical and social circumstances obtained from social care, specialist drug treatment, mental health, non-statutory services, the Scottish Prison Service and Criminal Records Office was collated. More than 70% (n = 237) were seen 6 months prior to their drug death. Sociodemographic details were reported much more frequently than medical problems, for example, ethnicity (49%), living accommodation (66%), education and income (52%) and dependent children (73%). Medical and psychiatric history was recorded in only 12%, blood-borne viral status in 17% and life events in 26%. This paucity of information was a feature of treatment plans and progress recorded. The 237 drug deaths were not a population unknown to services. Highly relevant data were missing. Improved training to promote in-depth recording and effective monitoring may result in better understanding and reduction of drug deaths.

Objective To assess predictors of mortality in a population of people prescribed methadone. Design Retrospective cohort study. Setting Geographically defined population in Tayside, Scotland. Participants 2378 people prescribed and dispensed liquid methadone between January 1993 and February 2004. Main outcome measures All cause mortality (primary outcome) and drug dependent cause specific mortality (secondary outcome) by means of Cox proportional hazards models during 12 years of follow-up. Results Overall, 181 (8%) people died. Overuse of methadone (adjusted hazard ratio 1.67, 95% confidence interval 1.05 to 2.67), history of psychiatric admission (2.47, 1.67 to 3.66), and increasing comorbidity measured as Charlson index ≥3 (1.20, 1.15 to 1.26) were all associated with an increase in all cause mortality. Longer duration of use (adjusted hazard ratio 0.95, 0.94 to 0.96), history of having urine tested (0.33, 0.22 to 0.49), and increasing time since last filled prescription were protective in relation to all cause mortality. Drug dependence was identified as the principal cause of death in 60 (33%) people. History of psychiatric admission was significantly associated with drug dependent death (adjusted hazard ratio 2.41, 1.25 to 4.64), as was history of prescription of benzodiazepines (4.35, 1.32 to 14.30). Conclusions Important elements of care in provision of methadone maintenance treatment are likely to influence, or be a marker for, a person’s risk of death.

Defectivity requirements are constantly put to new standards, even in older factories where new toolsets aren't a feasible alternative. To prolong the life of this equipment, Integrated Designs has created the digital dispense valve system. Tracks with older pump systems are plagued with repeatability and suckback issues that are key factors in eliminating or reducing defectivity. The digital dispense system not only increases the pump's capability to hold suckback across significant amounts of idle time regardless of viscosity, but also allows for lower dispense volumes due to more repeatable dispenses. Combining these factors results in a significant decrease in defectivity with only minor equipment additions, that previously would have required costly pump and track upgrades.

In order to address new technology requirements, Spray Photoresist Dispense Processing has been developed to aid in the manufacturing of High Aspect Ratio devices. The choice of process pump to affect the Spray Process is critical to the results, as the dispense uniformity is greatly influenced by the type of pump used to supply fluid to the Ultra Sonic dispense nozzle. Previous methods used had insufficient ramp rate of the dispense output. The pressure on demand dispense unit has excellent ramp rate to required flow rate, and the Patented Control Technology provides stability within tolerance to improve overall uniformity. The implementation of this method will improve cycle time and reduce the processing cost of wafers.

Resist minimization techniques have been around since the mid-1990s. As the volume decreases, the accuracy of the systems must increase. These inaccuracies can negate any savings that could potentially be acquired due to rework or even scrap. This has become a problem for older factories with pumps that are not accurate below 2.0ml. In order to help with these issues, Integrated Designs has created the digital dispense valve. This mechanical addition can prolong the life of a pump and saving the costly pump replacement scenario. The digital dispense valve increases the accuracy at lower dispense volumes and give more repeatable suckback control than was previously available for this generation of pump systems.

The via-first process is unique by the fact that a material is needed to fill the vias to some arbitrary value, with little or no isolated-dense via bias so that the underlying layer underneath the via is protected from the trench etch step. Secondly, this material may have to coat over the surface of the wafer with some chosen thickness again with minimum or no bias to maximize the trench photolithography process window. Finally, the material must be easily removed from the via after the trench etch with no residue, crowning, or fencing. The ideal via fill material would be able to perform all the above listed parameters, but no perfect solution exists yet. The etchback process that is discussed herein, called the solvent etchback (SOLVE) process bypasses these lengthy modules, will fit within today’s manufacturing processes and will have little impact on throughput of the photobay coating tools. The process utilizes industry standard photoresists solvents such as PGMEA, Ethyl Lactate, PGME and existing solvent prewet dispense nozzles in the BARC coater module. Also, this process only requires one material that can both fill the via and act as a BARC during the trench photo step with a user defined thickness on top the wafer that will minimize light reflections coming from the substrate. The process flow for the SOLVE process is: 1. Coat a wafer with a thick BARC to planarize the wafer and minimize isolated-dense bias. 2. Bake the BARC so that it is partially crosslinked. 3. Apply a solvent to the wafer and etchback the BARC to a thickness that suits the trench photo step. 4. Bake the BARC to fully crosslink the BARC. Process variables that can have an affect on the SOLVE process are the softbake temperature and time to modify the BARC thickness on the wafer. Dispense parameters that will modify the post-etch uniformity of the wafer include the dispense time, dispense spin speed and the IDI M450 dispense pressure. The repeatability of the process can be modified by changing the solvent spin off speed and acceleration.

A design of experiment (DOE) was implemented to show the effects of various point of use filters on the coat process. The DOE takes into account the filter media, pore size, and pumping means, such as dispense pressure, time, and spin speed. The coating was executed on a TEL Mark 8 coat track, with an IDI M450 pump, and PALL 16 stack Falcon filters. A KLA 2112 set at 0.69 μm pixel size was used to scan the wafers to detect and identify the defects. The process found for DUV42P to maintain a low defect coating irrespective of the filter or pore size is a high start pressure, low end pressure, low dispense time, and high dispense speed. The IDI M450 pump has the capability to compensate for bubble type defects by venting the defects out of the filter before the defects are in the dispense line and the variable dispense rate allows the material in the dispense line to slow down at the end of dispense and not create microbubbles in the dispense line or tip. Also the differential pressure sensor will alarm if the pressure differential across the filter increases over a user-determined setpoint. The pleat design allows more surface area in the same footprint to reduce the differential pressure across the filter and transport defects to the vent tube. The correct low defect coating process will maximize the advantage of reducing filter pore size or changing the filter media.

A retrospective investigation of case-notes compared 54 incidents of informal psychiatric in-patients being detained in hospital on an emergency basis with 66 incidents of discharge against medical advice (AMA). The characteristics of the two groups were compared. Detained patients were more likely to have been detained previously, to be suffering from a psychotic illness, and to have threats of violence or self-harm mentioned in their case-notes. AMA patients were more likely to have a history of substance abuse but were no more likely than the detained group to have been discharged AMA in the past. The results suggest that psychiatrists in this hospital are using current legislation on detention appropriately.

Seasonal influenza vaccination is the most common medical procedure targeting the immune system and yet the extent to which influenza vaccination activates innate immunity in humans is not fully understood. Currently, the most prevalent formulations of the vaccine consist of degraded or “split” viral particles often prepared without any adjuvants. We sought to determine whether the unadjuvanted split influenza vaccine activates innate immune receptors—specifically Toll-like receptors. A mass-cytometry (CyTOF) based proteomic profiling platform was developed and used to compare signaling pathway activation and cytokine production between the split influenza vaccine and a prototypical TLR response in human whole-blood (ex vivo). This analysis revealed that the split vaccine rapidly and potently activates multiple immune cell types but yields a proteomic signature distinct from TLR activation. Importantly, vaccine induced activity was dependent upon the presence of human sera indicating that a serum factor was necessary for vaccine-dependent immune activation. We found this serum factor to be human antibodies specific for influenza proteins and therefore immediate immune activation by the split vaccine is immune-complex dependent. These studies demonstrate that influenza vaccine splitting inactivates any microbial adjuvants endogenous to influenza but potentially elicits a potent immune modulator by facilitating the rapid formation of immune complexes.

AIMS: To determine the reasons patients seek excimer laser treatment for myopia and to measure levels of patient satisfaction with each phase of this relatively new treatment. METHODS: A unique 38 item visual analogue questionnaire was developed and applied to 100 consecutive patients (n = 100) who had undergone excimer laser photorefractive keratectomy for myopia or myopic astigmatism at a single centre. All subjects underwent extensive ophthalmic assessment and patient education before treatment. RESULTS: A 90% response rate was achieved (n = 90). Improved unaided vision (85.6%), freedom from spectacles (83.3%), and difficulties with contact lens wear (72.7%) were the most common reasons for seeking treatment. The majority of patients felt that the quality of their life had improved (85.5%) and 82% felt that the quality of their unaided vision was as good as they had anticipated. overall, 95.5% of patients were pleased that they had undergone this procedure. The vast majority (98.9%) of patients felt that they fully understood the operation pretreatment but almost one quarter (23.9%) found the actual operation distressing. Only 15.7% found postoperative pain did not respond adequately to prescribed analgesia. CONCLUSIONS: This study demonstrates a very high level of patient satisfaction after excimer laser treatment for myopia and myopic astigmatism. It suggests that most patients seek treatment to enjoy better vision free from optical aids and that a high level of patient education preoperatively may establish realistic expectations and satisfaction with overall outcome.

“How is it possible to expect mankind will take advice, when they will not so much as take a warning” Jonathan Swift, Thoughts on Various Subjects (1711) “There are some things you learn best in calm, and some in storm” Willa Sibert Cather, The Song of the Lark (1915) It is generally

Oral vaccines for polio (OPV) and rotavirus have been shown to be much less effective in poor children in the developing world. The reason(s) for oral vaccine failure in this setting has been unknown. We hypothesized that failure of orally administered vaccines such as OPV was due to tropical enteropathy and resultant inflammation from endotoxin exposure. We tested this hypothesis in a cohort of children followed from birth in an urban slum of Dhaka Bangladesh. Response to oral poliovirus vaccine was measured in the children who received the recommended minimum of three doses of OPV by age 6 months. Diminished antibody responses to OPV were associated with malnutrition, serum endotoxin-specific antibodies, and shorter breastfeeding duration. In a subset of these children, we investigated the mechanism for vaccine failure using a systems-immunology approach, performing comprehensive cellular assays on peripheral blood mononuclear cells, including a single-cell mass-spectrometry based assessment of cellular phenotypes and functional capacities. From this analysis, children with vaccine failure exhibited globally reduced cellular responsiveness to a range of cytokine stimulations, as well as elevated pro-inflammatory cytokine expression. These data indicate that oral vaccine failure in this at-risk group is related to malnutrition, gut barrier dysfunction and shorter duration of breast-feeding in early childhood, and is associated with a chronic inflammatory immune phenotype.

Vaccination is the most effective strategy to prevent and control infectious diseases through induction of antibodies that neutralize the pathogen. However, little is known on what immune traits underlie an effective antibody response. With the aim of finding correlates of vaccine response that predict the antibody titers against an influenza vaccine, we studied the antibody responses to the seasonal trivalent influenza vaccine in a young and older individuals, and assayed a comprehensive set of immune parameters that included whole blood gene expression, determination of serum cytokine levels, leukocyte subset frequencies and phosphorylation of signaling proteins upon stimulation of various peripheral blood cells. We have found that rise in antibody titers to influenza strains after vaccination is strongly associated with high pro-apoptotic and low cell survival/proliferation levels of diverse immune traits and genes that could be exploited to improve vaccine responses in those less protected.

Sir: Recent papers on psychiatrists' safety raise important issues. Davies reaffirms the view that psychiatrists are vulnerable to violence ( Psychiatric Bulletin , March 2001, 25 , 89-91). Osborn and Tang demonstrate the ineffectiveness of audit in ensuring that interview rooms are safe (

Immune system function generally degrades with age and is associated with increased risk of infection and disease. Though differences between young and old have been noted in many immune system components, no system wide understanding of how these disparate observation act together exists to date, nor how they relate to genes found to associated with increased longevity, many of which are immune related. Here we characterize the immune system of 29 young and old individuals by concurrently measuring from peripheral blood, immune cell subset frequency, serum cytokines, gene expression and individual cellular responses to cytokine stimuli by pathway specific phospho-protein abundance. We identify age-dependent changes in STAT signaling baseline and in response to stimulation by a panel of 7 different cytokines, particularly prominent in CD8 and CD4 T cells, but also in monocytes and B-cells. The observed differences in cellular responses are not due to adaptation to higher level of cytokine stimuli but rather to an inert inability to mount a full response, many times augmented by a higher base line phosphorylation level in the elderly. We construct an immune network spanning multiple biological layers and identify co-occurring modules which link longevity associated genes with these cellular immune phenotypes. We quantify the contributions of these modules to the observed reduction in cellular response to stimuli in the elderly and suggest a common responsible mechanism.

Aging is a complex process in which the immune function is severely affected. Increased prevalence of infectious diseases and poor vaccine responses are characteristic in the elderly. Here we seek to define the immune response to the seasonal inactivated Influenza vaccine in young subjects and in an elderly population with the aim of finding signatures of immune health and immune senescence. Ninety-one subjects, age-ranges 20-30, 60-79 and 80-96, were drawn prior to the vaccine, 7 and 21 days after vaccination. PBMC were isolated to phenotype 18 immune cell subsets and for high-throughput analysis of signaling phosphoproteins in multiple cell-subsets, after various stimulations. Serum samples were used to determine cytokine levels and antibody titers to the vaccine strains and to non-circulating Influenza strains. Dramatic age-related changes in STAT signaling were observed in CD8 and CD4 T cells when stimulated with IL-6, IFN-α or IFN-γ. The level of PLCγ phosphorylation in B cells from older subjects was significantly lower than the observed in the younger group, independently of the reduced B cell frequency. Weak antibody response against the vaccine strains while high level of seroprotection against older non-circulating vaccines was seen in the elderly and strongly associated to the IL-6 or IFN-α pathways. A better comprehension of human immune aging is necessary for designing age-specific vaccines with higher efficacy.

EDITOR,—Brigitta Bende and Robin M Philpott report on a patient with post-traumatic symptoms 50 years after the precipitating events who improved after appropriate treatment.1 The NHS could do a great deal to treat post-traumatic symptoms in its own workers and so ensure that as few as possible develop similar syndromes. One study found that up to 61% of clinical staff who report assaults by patients experience symptoms of post-traumatic stress disorder, and 10% meet the criteria for …

Many psychiatric training schemes hold induction days for their new junior doctors. This practice has now become a College recommendation and has frequently been a mandatory requirement for the approval of training schemes by the Royal College of Psychiatrists (Sims, 1990). Such days often concentrate on orientating the new trainee, looking in particular at facilities rather than the development of skills.

The content of delusions can reflect recent changes or developments within the environment.We describe three cases which illustrate, to our knowledge for the first time, the incorporation of Satellite Television Dishes within the experience of psychosis.

Aggression directed towards health care workers has been widely discussed (Health Services Advisory Committee, 1987), but information relating to British psychiatry has been anecdotal. The Collegiate Trainees' Committee (CTC) has recently expressed concern about the apparent dearth of training opportunities in the recognition and management of aggression, and the difficulty in obtaining post-incident counselling (1991).

The first meeting of the Violence Management Special Interest Group on 25 February 1992 drew a mixed group of delegates from three of the 15 Scottish Health Boards, three Regional Social Work Departments and several Education Departments, as well as the Scottish Prison Service. The majority of those who attended were actively engaged in designing training programmes for public sector staff.

BACKGROUND: Patients presenting for photorefractive keratectomy (PRK) may have unusual psychological profiles. Certain psychological variables may impact treatment outcome, making early identification crucial. We report a controlled questionnaire study of psychiatric "anxiety/distress'' and self-esteem in myopic patients who presented for excimer laser treatment. METHODS: Ninety consecutive myopic individuals (patients) who presented for excimer laser PRK and 50 consecutive myopic individuals who presented to an optometrist for contact lens fitting (controls) were assessed using two self-completion questionnaires-the GHQ30 and Hudson Index of Self-Esteem ISE. The questionnaires were distributed during assessment for treatment. RESULTS: PRK patients had a 90% response rate for both questionnaires and control patients, 98% for GHQ30 and 100% for Hudson ISE. PRK patients were significantly older (p=0.000003), had a greater myopic spherical equivalent refraction (p=0.012) and had better spectacle-corrected visual acuity (p=0.0096). No significant differences were demonstrated with regard to anxiety/distress in terms of absolute scores (p=0.07), or the proportion of patients being positive or negative (p=0.10). Similarly, self-esteem was not significantly different between the two groups (absolute scores p=0.69; positive/negative p=0.29). The high response rate shows that the GHQ30 and Hudson ISE are easy to use and well tolerated by myopes in a busy clinic setting. The fact that the patients were older, with a greater refractive error, may partly reflect the onset of contact lens intolerance. CONCLUSION: The psychological findings suggest that PRK patients cannot be considered more distressed or anxious than other myopic individuals. There is no evidence that their decision to undergo surgery is driven by abnormally low selfesteem. [J Refract Surg 1997;13:40-44]