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- Gustafsson, Per E, 1981-
(författare)
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Psychosocial Stress, Mental Health and Salivary Cortisol in Children and Adolescents
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stressful experiences and conditions in childhood influence the health and well-being of the growing individual, and can also confer a long-lasting impact into adult life. Delineating the social, mental and biological aspects of stress in children and adolescents is therefore of great concern for human beings. Despite these notions, much knowledge is lacking regarding stress in childhood.This thesis aimed at examining diverse aspects of stress in children and adolescents: associations between social conditions, traumatic life events, mental health, and salivary cortisol as a measure of the activity of a major physiological stress system. Cross-sectional samples included two non-clinical samples of school-aged children (N=240-336) and adolescents (N =400), and two clinical samples of children with obsessive-compulsive disorder (OCD) (N =23) and adolescents who had experienced childhood abuse (N =15). Main measures were salivary cortisol sampled three times a day, and questionnaires to teachers, parents and children with questions about each child’s mental health, traumatic life events and about the socioeconomic situation of the parents.The main findings include observation of 1) higher cortisol levels in children with a moderate level of psychosocial burden (low socioeconomic status, immigrant family, social impairment of mental health problems), 2) higher cortisol levels in children with OCD who also displayed a tendency to decreasing cortisol in the face of an acute stressor, and 3) cortisol was positively related to mental health problems in abused adolescents. Furthermore, the deleterious effect of 4) traumatic events involving a social dimension, interpersonal traumas, and 5) cumulative traumatic events, polytraumatization, on the mental health of children and adolescents was indicated.The findings are discussed with respect to the complex interactions between social, mental and biological aspects of children and adolescents. The consequences of adverse experiences in childhood may represent pathways to future health problems. Consideration of the social circumstances in childhood might in the future guide public health policies and the identification of target groups for preventive interventions as well as leading to improvements in treatment for children exposed to severe stress.
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- Bengtsson, Ingemar, et al.
(författare)
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Marknadsanalys
- 2024. - 15
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Ingår i: Fastighetsnomenklatur : Fastighetsekonomi och fastighetsrätt. Institutet för värdering och Samhällsbyggarna. - Fastighetsekonomi och fastighetsrätt. Institutet för värdering och Samhällsbyggarna.. - 9789144182636 - 9789144191072 ; , s. 263-285
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Bokkapitel (populärvet., debatt m.m.)abstract
- Marknadsanalys handlar i fastighetssammanhang i grunden om att undersöka fastighetsmarknaden i syfte att förstå hur fastigheter prissätts på marknaden. Det i sin tur handlar både om att förstå hur fastigheter i allmänhet prissätts och hur specifika fastigheter prissätts. Det förstnämnda handlar om prisnivån på fastighetsmarknaden och det andra om priset på en specifik fastighet. Det här kapitlet handlar om hur man kan strukturera en marknadsanalys i samband med att man värderar en fastighet och vilka faktorer som behöver undersökas. Kapitlet baseras på beskrivningen av marknadsanalys i läroboken Fastighetsvärdering – om värdeteori och värderingsmetoder (2023) av samma författare. Föreliggande text är en komprimerad och delvis omskriven version av flera olika kapitel i nämnda bok. Fokus ligger här på kommersiella fastigheter och bostadshyreshus, vilka också ryms inom begreppet avkastningsfastigheter.
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- Bergman, Kerstin, et al.
(författare)
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Ska vi äta våra döda: Linné mellan tro och nytta
- 2002
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Ingår i: I ordets smedja: Festskrift till Per Rydén. - 9172034947 ; , s. 182-191
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- About the struggle between faith and utilitarian aspects in the writings of Carl von Linné.
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- Bondesson, Maria, et al.
(författare)
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A CASCADE of effects of bisphenol A.
- 2009
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 28:4, s. 563-7
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Tidskriftsartikel (refereegranskat)
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- Calles, Olle, et al.
(författare)
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Anordningar för upp- och nedströmspassage av fisk vid vattenanläggningar : Underlag till vägledning om lämpliga försiktighetsmått och bästa möjliga teknik för vattenkraft
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Många kraftverksdammar saknar idag fiskvägar för uppströms vandrande fisk och de flesta för nedströmsvandrande fisk. Litteraturgenomgången visar att passage av fisk via turbinerna ofta ger omfattande skador och dödlighet och därmed inte är en tillfredsställande förvaltningsstrategi. Det bedöms vara tekniskt fullt möjligt att bygga väl fungerande fiskvägar för samtliga förekommande fiskarter i alla svenska vattensystem. I detta dokument ges rekommendationer om hur fiskvägar bör anläggas, designas och skötas för att nå god anlocknings- och passageeffektivitet för såväl uppströms- som nedströmsvandrande fisk. Att relativt många fiskvägar fungerar dåligt beror på att uppföljning, tillsyn och kontroll av deras effektivitet är eftersatt eller ofta helt saknas. Att etablera en fungerande fiskväg är en process som kan ta flera år då successiva justeringar behövs. Det går dock att få till bra passagelösningar, även förbi stora kraftverk med höga dammar.För uppströmsvandring rekommenderas i första hand naturlika fiskvägar, som omlöp, eftersom de passar de flesta arter och storlekar. Omlöpen kan även fungera som nya strömhabitat och därmed ersätta något av de strömhabitat som förlorats. Är det enbart laxfisk eller andra goda vandrare som skall passera kan en teknisk fiskväg vara en godtagbar lösning. Även i områden med branta dalsidor som gör det svårt att anlägga naturlika fiskvägar och i områden med kulturmiljöer kan tekniska fiskvägar vara ett alternativ. Fiskslussar och fiskhisssar har låg effektivitet och kan inte rekommenderas generellt.Väl fungerande fiskpassager bör föra vatten under en stor del av året såvida inte fiskvägen är inriktad på en enskild art med väl kända behov. Naturlika fiskvägar bör, i likhet med naturliga vattendrag, ha en fastställd minsta vattenföring som är tillräcklig för att bevara sträckans habitatvärden.Ett vanligt problem är att det används för lite vatten i fiskvägen för att locka fisken till mynningen i tillräckligt hög utsträckning. Ofta behöver extra lockvatten användas för att få fisken att hitta fiskvägen, eller fiskvägarna eftersom det i breda vatten kan vara nödvändigt att ha flera fiskvägar, och vid behov även flera ingångar till fiskvägarna. Lockvattnet bör minst utgöra 5 % av medelvattenföringen på platsen, men det kan i vissa situationer behövas ännu mer vatten, och vid högflöden bör även lockvattnet öka i paritet med detta. Extra lockvatten behöver inte gå i fiskvägen utan kan ledas till fiskvägens nedre öppning.Vid nedströmspassage skall anpassade låglutande galler, fiskgaller, användas som leder fisken till en eller flera passagemöjligheter. Spaltvidden mellan gallren ska vara sådan att fisken inte passerar, vilket för vissa arter innebär att spaltvidden inte tillåter fysisk passage av fisk, medan det för andra arter räcker att gallret är en beteendemässig barriär. Idealt skall fisken aldrig komma i direkt med gallret utan ledas rätt väg. I mycket stora älvar kan spjälgaller (louvers) vara ett alternativ, men referensexempel saknas i Sverige i dag, alternativet är låglutande fiskgaller. Beteendeavledning (ljus, ljud, el, bubblor) bör endast användas som åtgärd i kombination med en fysisk avledare, eller på de platser där en fysisk avledare av någon anledning bedöms vara omöjlig att uppföra.Utformningen av flyktöppningen är också essentiell för avledarens funktion. För att tillgodose olika arters djuppreferens, kan man antingen placera en flyktöppning i ytan och ytterligare en vid botten (ål). Den vanligaste rekommendationen är att flyktöppningen ska vara successivt avsmalnande, för att åstadkomma en gradvis acceleration utan turbulens. Flyktöppningens, och därmed hela åtgärdens, funktion är beroende av den mängd vatten som tappas i förbipassagen. Enkelt uttryckt, kan man säga att ju mer vatten som tappas genom förbipassagen, desto större sannolikhet att den funkar väl. Internationellt rekommenderas att 2–10 % av det totala flödet används för att säkerställa nedströmspassage, varför rekommendationen är att överdimensionera flyktöppningar för att under åtgärdens driftsättande undersöka vilket flöde som krävs för god funktionDet bör betonas att den rödlistade ålen kräver speciella anpassningar vid varje hinder för dess upp- och nedvandring. Rekommendationer på bra åtgärder ges i dokumentet. Kriterier för anlocknings- och passageeffektivitet (upp- och nedströms) i fiskvägar bör fastställas utgående från förekomst av långvandrare (lax, havsöring, ål, flodnejonöga, havsnejonöga), antalet hinder och den geografiska lokaliseringen av lämpliga habitat. Litteratursammanställningen visar att många befintliga fiskvägar inte fungerar som avsett och bör utvärderas om minsta osäkerhet råder om deras funktion. Utvärderingarna bör ligga till grund för förbättringar av passagerna till dess tillräcklig effektivitet erhålls och resultaten tillställs tillsynsmyndigheten.
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- Elander, Ingemar, et al.
(författare)
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The re-emergence of local self-government in Central Europe : some notes on the first experience
- 1993
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Ingår i: European Journal of Political Research. - : Wiley. - 0304-4130 .- 1475-6765. ; 23:3, s. 295-322
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Tidskriftsartikel (refereegranskat)abstract
- In the current transitional period in Central Europe two issues have been commonly regarded as outstanding: the democratization of national political systems and the transformation of national economies into capitalist ones. However, in the long run, the reintroduction of local self-government may be even more decisive when it comes to the stabilization of the post-socialist societies. Firstly arguing that local self-government is a crucial link between state and civil society, the paper goes on to review the local government system during socialism. This is followed by overviews of attempts to change this system in Poland, Hungary and Czechoslovakia. A number of hopes and fears associated with this development are highlighted, then the concluding section discusses the gains to be made for comparative political research by considering the local governments of Central Europe.
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- Gustafsson, Ingemar, et al.
(författare)
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An inter-day assessment of the ABC parameters in the evaluation of progressive keratoconus
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The progression of keratoconus is commonly determined by comparing the results of corneal tomographic measurements on different occasions. However, investigations on the repeatability of measurements are commonly performed within the same day, thus not taking the inter-day variation into account. The effect of keratoconus disease severity on the measurement error is also seldom considered. In this post hoc investigation, the parameters A, B and C in the Belin ABCD Progression Display were evaluated in relation to disease severity in intra-day and inter-day measurements. Four consecutive measurements were performed on 61 patients with keratoconus on the same day (intra-day). In another cohort, four consecutive measurements were obtained and then repeated 3 days later in 25 patients with keratoconus and 25 healthy controls (inter-day). The results suggest that the diagnosis of disease progression would benefit from inter-day measurements, and the stratification of the parameters A and C according to disease severity. It is also recommended that tomographic systems such as the Pentacam HR be modified to allow the comparison of both single measurements and the mean of replicate measurements of the parameters used in the assessment of progression of keratoconus.
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- Gustafsson, Ingemar, et al.
(författare)
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Association between keratoconus disease severity and repeatability in measurements of parameters for the assessment of progressive disease
- 2020
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Progressive keratoconus can lead to severely impaired vision, but there is currently no consensus on the definition of progressive disease. Errors in the measurement of the parameters commonly used to establish progressive disease were evaluated in an attempt to determine the limits at which a true change in the values can be detected. The possible association between measurement error and disease severity was also investigated to evaluate the need for limits based on disease severity. Methods Sixty-one eyes were studied in 61 patients with keratoconus. Four replicate measurements were made in each patient using a Scheimpflug-based tomographic system (denoted the PC) and an auto-keratometer (denoted the AK). The repeatability coefficient, i.e., the level below which differences between two measurements are found in 95% of paired observations, was calculated. Patients were further divided into three groups based on disease severity (parameter magnitude). Results Increasing magnitude of all the keratometric parameters investigated was significantly associated with increasing measurement errors, and thus worse repeatability. The maximum keratometry value (Kmax) was the least repeatable parameter (1.23 D, 95% CI 1.11–1.35 D) and showed the strongest association between parameter magnitude and measurement error. The repeatability coefficient ranged between 0.32 and 1.62 D, depending on disease severity. The most repeatable parameter was the flattest central keratometry value (K1), measured with the PC (0.51 D, 95% CI 0.46–0.56 D) and the AK (0.54 D, 95% CI 0.48–0.59 D). K1 showed the weakest association between parameter magnitude and measurement error. The repeatability coefficient for K1 ranged between 0.40 and 0.54 D when using the PC, and between 0.34 and 0.70 D when using the AK in the three groups. Conclusions The association between the magnitude of the keratometric parameters and their measurement errors suggests that limits should be based on disease severity to ensure reliable detection of progressive keratoconus. Further studies are, however, required.
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- Gustafsson, Ingemar, et al.
(författare)
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Current clinical practice in corneal crosslinking for treatment of progressive keratoconus in four Nordic countries
- 2023
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-3768 .- 1755-375X. ; 101:1, s. 109-116
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate clinical practice in the diagnosis and treatment of progressive keratoconus with corneal crosslinking (CXL) in four Nordic countries.METHODS: A questionnaire was sent to all centres at which keratoconus patients are evaluated and CXL is performed in Sweden, Denmark, Norway and Iceland. Nineteen of 20 centres participated.RESULTS: CXL is performed approximately 1300 times per year in these four Nordic countries with a population of around 21.7 million (2019). In most cases, progression is evaluated using the Pentacam HR, and the maximum keratometry reading (Kmax ) is considered the most important parameter. The most frequently used treatment protocol in Scandinavia is the 9 mW/cm2 epi-off protocol, using hydroxylpropyl methylcellulose riboflavin (HPMC-riboflavin). The participants deemed the following areas to be in most need of improvement: adaptation of the CXL protocol to individual patients (5/19), the development of effective epi-on treatment protocols (4/19), optimal performance of CXL in thin corneas (4/19), improvement of the definition of progression (2/19), and diagnosis of the need for re-treatment (2/19).CONCLUSIONS: We concluded that the diagnosis of progressive keratoconus and the diagnostic equipment used are similar. Treatment strategies are also similar but are suitably different to provide an interesting basis for the comparison of treatment outcomes. The high degree of participation in this survey indicates the possibility of future scientific collaboration on CXL focusing on the areas deemed to need improvement. It would also be of interest to evaluate the possibility of creating a Nordic CXL Registry. The high number of CXL treatments performed ensures sufficient statistical power to solve many questions. Such a registry could be an important contribution to evidence-based care and would allow for longitudinal evaluation.
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- Gustafsson, Ingemar, et al.
(författare)
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Early findings in a prospective randomised study on three cross-linking treatment protocols : Interruption of the iontophoresis treatment protocol
- 2023
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Ingår i: BMJ Open Ophthalmology. - 2397-3269. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To present the outcome of the interrupted iontophoresis-assisted treatment arm in an ongoing randomised clinical trial (NCT04427956). Methods A randomised clinical study of corneal cross-linking (CXL) using continuous UV-A irradiation at a rate of 9 mW/cm 2 and three different types of riboflavin and riboflavin delivery mode: (1) iso-osmolar dextran-based riboflavin (epithelium-off), (2) hypo-osmolar dextran-free riboflavin (epithelium-off) and (3) iontophoresis-assisted delivery of riboflavin (epithelium-on) for the treatment of progressive keratoconus. Inclusion criteria were an increase in the maximum keratometry value (Kmax) of 1.0 dioptre over 12 months or 0.5 dioptre over 6 months. The primary outcome in evaluating treatment efficacy was Kmax. Recently presented stratified detection limits were used post hoc to confirm the enrolment of patients with truly progressive keratoconus and in the assessment of the need for re-CXL. Results Thirteen patients had been randomised to iontophoresis-assisted CXL when the treatment arm was interrupted; two patients dropped out. Of the remaining 11 patients, 7 were deemed as having truly progressive disease according to the more recent stratified detection limits. The disease continued to progress in three patients according to the original definition (increase in Kmax≥1 D), necessitating re-CXL with epithelium-off CXL. This progression was confirmed by post hoc analysis using the stratified detection limits for progression. Conclusions The iontophoresis-assisted CXL protocol failed to halt further disease progression in 27% of the patients. The failure rate increased to 38% when considering only the patients deemed to have truly progressive disease using the stratified detection limits.
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- Gustafsson, Ingemar, et al.
(författare)
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Early findings in a randomised controlled trial on crosslinking protocols using isoosmolar and hypoosmolar riboflavin for the treatment of progressive keratoconus
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Ingår i: Acta Ophthalmologica. - 1755-3768. ; , s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo present baseline characteristics and to present the perioperative corneal thickness during corneal crosslinking (CXL) treatment for progressive keratoconus and to describe how the addition of sterile water (SW) efficaciously can maintain the corneal thickness. The treatment efficacy will be evaluated when the 1-year follow-up is complete.MethodsA randomised clinical study using epithelium-off CXL with continuous UVA irradiation (9 mW/cm2) and two kinds of riboflavin solutions: (i) isoosmolar dextran-based riboflavin (n = 27) and (ii) hypoosmolar dextran-free riboflavin (n = 27). Inclusion criteria: progressive keratoconus with an increase in maximum keratometry value (Kmax) of 1.0 dioptre (12 months) or 0.5 dioptres (6 months). Corneae thinner than 400 μm were also included. Outcome parameters: Perioperative corneal thickness and the effect of adding SW.ResultsSeventy-four per cent of the patients in the isoosmolar group and 15% in the hypoosmolar group required the addition of SW, which effectively maintained a corneal thickness of 400 μm in all cases during CXL. The addition of SW was primarily needed during the irradiation procedure and not the preoperative soaking period.ConclusionsEspecially during the CXL irradiation phase, isoosmolar riboflavin causes a significant dehydrating effect leading to corneal thinning during CXL. The customised addition of SW is efficacious in maintaining the corneal thickness during CXL and could increase the safety of the procedure.
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- Gustafsson, Ingemar
(författare)
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Education in the New Architecture of Aid
- 2010
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Ingår i: Education and Development in the Context of Globalization. - : Nova Science Pub Inc. - 9781617285080
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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18. |
- Gustafsson, Ingemar, et al.
(författare)
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Introducing a new tool for the assessment of progressive keratoconus: the Scandinavian Keratoconus Progression Application
- 2022
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Ingår i: Journal of EuCornea. - : EuCornea. - 2452-4034. ; 11:3, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo develop an application for the Pentacam HR for the purpose of optimising the accuracy of the diagnosis of progressive keratoconus.MethodsMeasurements were performed on one randomised eye in twenty-five subjects with keratoconus Stage 1-2 according to the Amsler-Krumeich classification on two occasions, three days apart. Four replicate measurements were made by a single examiner on each occasion. The inter-day repeatability and detection limits for the diagnosis of progressive keratoconus were calculated for the following parameters: K2 and Kmax, and the parameters A, B and C from the Belin ABCD Progression Display. The measurements used as input are automatically extracted from the Pentacam HR database as comma-separated values. The application, developed in the R programming environment, provides a web browser-based user interface that presents these parameters both numerically and graphically.ResultsThe application includes detection limits for the diagnosis of progressive keratoconus obtained from two previous studies on the inter-day repeatability of measurements in subjects with keratoconus. The detection limits are based on inter-day repeatability, stratified according to disease severity, allowing the comparison of single measurements or a mean of four replicates.ConclusionsThis is the first application to provide an assessment of progressive keratoconus using detection limits based on inter-day repeatability. We believe this application will contribute to the more accurate diagnosis of progressive keratoconus. It also facilitates diagnosis and improves the clinical workflow as all the relevant information is presented numerically, graphically, and colour-coded in one interface.
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19. |
- Gustafsson, Ingemar, et al.
(författare)
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Patient experience and repeatability of measurements made with the Pentacam HR in patients with keratoconus
- 2023
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Ingår i: BMC Ophthalmology. - 1471-2415. ; 23:1, s. 201-201
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To investigate whether the repeatability of measurements with the Pentacam HR in patients with keratoconus is improved by patients gaining more experience of the measurement situation. Such an improvement could enhance the accuracy with which progressive keratoconus can be detected. METHODS: Four replicate measurements were performed on Day 0 and on Day 3. Parameters commonly used in the diagnosis of progressive keratoconus were included in the analysis, namely the flattest central keratometry value (K1), the steepest central keratometry value (K2), the maximum keratometry value (Kmax), and the parameters A, B and C from the Belin ABCD Progression Display. In addition, quality parameters used by the Pentacam HR to assess the quality of the measurements were included, namely the analysed area (front + back), 3D (front + back), XY, Z, and eye movements. RESULTS: Neither the diagnostic parameters nor the quality parameters showed any statistically significant improvement on Day 3 compared to Day 0. The quality parameter "eye movements" deteriorated significantly with increasing Kmax. CONCLUSION: Gaining experience of the measurement situation did not increase the accuracy of the measurements. Further investigations should be performed to determine whether the increasing number of eye movements with increasing disease severity has a negative effect on the repeatability of the measurements.
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22. |
- Gustafsson, Ingemar
(författare)
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The assessment of disease progression in keratoconus and corneal crosslinking in thin corneae
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Keratoconus generally manifests in adolescents, and can progress leading to severely impaired vision. The risk of progression is inversely correlated to age; thus younger patients are at higher risk than older ones. Progressive keratoconus can be halted by corneal crosslinking (CXL). The general indication for CXL is progressive keratoconus, although children are commonly treated with CXL upon diagnosis. Tomography is used to assess progression, and the most commonly used system is the Pentacam HR. Measurements made on different visits are compared to determine whether the patient’s keratoconus has progressed, and they should be referred for CXL. However, there is no consensus on which parameters should be used, or the change in magnitude of these parameters that indicates progression. An increase in the curvature power of the steepest point on the anterior surface, Kmax, of 1.0 dioptres is commonly used for all patients. However, there is little evidence that this is appropriate. Furthermore, inconsistent results have been presented regarding the magnitude at which progression can be detected. Such studies are often based on determinations of the repeatability of measurements made on one occasion. However, the progression of keratoconus is evaluated from measurements made on different occasions, and it is reasonable to assume that measurements obtained on different days will be subject to greater variation due to the biomechanical instability of corneae affected by keratoconus. Also, it has been suggested in studies that the repeatability of measurements in subjects with more severe keratoconus have poorer repeatability. Another important aspect of keratoconus is that it is a thinning disorder. A minimum corneal thickness of 400 µm has been suggested for the safe performance of CXL. Thus, a significant proportion of keratoconus patients will be excluded from the standard CXL treatment protocol.Thus, in the first study we elucidated the association between measurement error and disease severity. In the second investigation we investigated the inter-day repeatability and in the third investigation we investigated the Belin ABCD Progression Display. In the fourth study we investigate a protocol in which sterile water was added during the crosslinking procedure to increase the corneal thickness. The results demonstrated that the measurement error is associated to the disease severity and that limits at which progression is defined should be defined by inter-day measurements. The results also suggest that the diagnosis of progressive keratoconus by the Belin ABCD Progression Display will lead to overdiagnosis of progression. Further, the results suggest that the addition of sterile water is effective in increasing the corneal thickness above the suggested safety limits. These results have important clinical implications. The results demonstrate that limits at which progression is defined should be stratified according to the severity of the disease. Patients with less advanced keratoconus will be underdiagnosed as progressive if commonly used parameters are not stratified according to disease severity. This could lead to delayed referral for CXL, resulting in an avoidable risk of deterioration in vision. Patients with more advanced keratoconus, on the other hand, would be overdiagnosed as progressive, which could lead to unnecessary CXL, thus subjecting the patient to discomfort and possible treatment-associated complications. This risk of overdiagnosis of progression is also relevant when using the Belin ABCD Progression Display. Further, The data suggest that such a simple measure as adding sterile water during corneal crosslinking could enhance the corneal thickness above safety limits.
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23. |
- Gustafsson, Ingemar, et al.
(författare)
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The Interday Repeatability of Parameters for the Assessment of Progressive Disease in Subjects With Less Advanced Keratoconus
- 2021
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Ingår i: American Journal of Ophthalmology. - : Elsevier BV. - 0002-9394. ; 225, s. 38-46
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the interday repeatability in the measurement of parameters used for the detection of progression of keratoconus by prediction limits (PL) for single measurements, and the repeatability coefficient (RC) for the mean of replicate measurements. Design: Prospective reliability analysis for cases and control eyes. Methods: Twenty-five eyes in 25 subjects with KC and 25 eyes in 25 healthy controls were included. Four consecutive measurements were made, 3 days apart, with a Pentacam HR tomographic instrument (denoted the Pentacam) and a Nidek ARK 560-A auto-keratometer (denoted the keratometer). Main outcome measures were the intra- and interday RC of parameters used in the detection of progression of keratoconus. Results: The most repeatable parameter obtained with the Pentacam was the curvature power of the central flat meridian (K1, 0.44 D [RC], -0.55 to 0.60 diopter [D] [PL]), followed by the central steep meridian (K2, 0.72 D [RC], -0.90 to 0.94 D [PL]). The interday repeatability of K1 and K2 was similar when using the keratometer (K1, 0.32 D [RC], -0.66 to 0.57 D [PL], K2, 0.93 D [RC], -1.36 to 1.08 D [PL]). The interday repeatability of the curvature power of the steepest point (Kmax, 0.84 D [RC], -0.90 to 1.11 D [PL]) would benefit from being stratified: RC = 0.44 D and PL = -0.49 to 0.67 D for Kmax < 49.0 D, and RC = 1.08 D and PL = -1.19 to 1.42 D for Kmax ≥ 49.0 D. Conclusions: The interday repeatability of measurements, single or replicate, in subjects with keratoconus should be considered when diagnosing progressive disease. K1 exhibited the best intraday repeatability. Kmax benefits from being stratified according to disease severity.
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24. |
- Gustafsson, Ingemar, et al.
(författare)
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The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- The healthy cornea is transparent, however, disease can affect its structure, rendering it more or less opaque. The ability to assess the clarity of the cornea objectively could thus be of considerable interest for keratoconus patients. It has previously been suggested that densitometry can be used to diagnose early keratoconus, and that the values of densitometry variables increase with increasing disease severity, indicating that densitometry could also be used to assess progressive keratoconus. Previous studies have only assessed the repeatability of corneal densitometry measurements on the same day, which does not reflect the clinical setting in which changes are evaluated over time. We have therefore evaluated the inter-day repeatability of densitometry measurements in both patients with keratoconus and healthy controls. Measurements in the middle layer of the 2-6 mm zone of the cornea showed the best repeatability. Although an objective measure of the corneal transparency could be interesting, the generally poor repeatability of densitometry measurements limits their use. The repeatability of corneal clarity measurements could be improved by using other approaches such as optical coherence tomography, but this remains to be investigated. Such improvements would allow the more widespread use of corneal densitometry in clinical practice.
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