Anterior segment optical coherence tomography angiography:Development and application of OCT angiography for corneal vascularisation

Hoornvliesziekten behoren tot de meest voorkomende oorzaken van blindheid in de wereld. Vascularisatie van het hoornvlies is een veelvoorkomende en potentieel visusbedreigend probleem; het gezonde hoornvlies heeft geen vaten en vascularisatie is het gevolg van in principe ieder ontstekingsproces waarbij het hoornvlies is betrokken. De huidige gouden standaard voor beeldvorming van vascularisatie is invasief; het vereist injectie van een intraveneuze contrastvloeistof (indocyanine groen, ICG). OCT-angiografie (OCTA) is een nieuwe, niet-invasieve beeldvormingstechniek die is ontwikkeld om de vaten van het netvlies te kunnen afbeelden. De huidige OCTA-systemen zijn echter niet geoptimaliseerd voor het hoornvlies. De hoofddoelen van mijn proefschrift zijn (1) om te laten zien dat OCTA-systemen die zijn ontworpen voor het netvlies (achtersegment van het oog) ook gebruikt kunnen worden voor het afbeelden van het hoornvlies (voorsegment van het oog), (2) om een methode te ontwikkelen om OCTA-beelden van het hoornvlies te analyseren en kwantificeren en (3) om OCTA te vergelijken met de huidige gouden standaard, te weten ICG-angiografie (ICGA), en met histologie en confocale microscopie. Het onderzoek beschreven in dit proefschrift opent de mogelijkheid voor een nieuwe, niet invasieve en snelle beeldvormingstechniek om het hoornvlies en de hoornvliesvaten tegelijk te evalueren. De resultaten ondersteunen dat deze nieuwe techniek in staat is om snel, veilig en betrouwbaar hoornvliesvaten te evalueren, met een goede correlatie met andere klinische instrumenten die in onze praktijk worden gebruikt, en met een mogelijkheid om veranderingen in de loop van de tijd waar te nemen.Corneal diseases are among the most common causes of blindness in the world. Vascularization of the cornea is a common and potentially vision-threatening problem; the healthy cornea has no vessels and vascularization is the result of every inflammatory process in which the cornea is involved. The current gold standard for imaging vascularization is invasive; it requires injection of an intravenous contrast fluid (indocyanine green, ICG). OCT angiography (OCTA) is a new, non-invasive imaging technique that has been developed to visualize the vessels of the retina. However, the current OCTA systems are not optimized for the cornea. The main goals of my PhD thesis are (1) to establish that OCTA systems designed for the retina (posterior segment of the eye) can also be used to image the cornea (anterior segment of the eye), (2) to to design a method to analyze and quantify OCTA images of the cornea and (3) to compare OCTA with the current gold standard, ICG angiography (ICGA), histology, and confocal microscopy. The research described in this thesis opens the possibility for a new, non-invasive and rapid imaging technique to evaluate the cornea and corneal vessels simultaneously. The results support that this new technique is capable of evaluating corneal vessels in a fast, safe, and reliable manner, with a good correlation with other clinical tools used in our practice, and with a possibility to observe changes over time. The same technique could also be used in a broader range of clinical applications in ophthalmology such as glaucoma

Integrating anticipative replenishment-allocation with reactive fulfillment for online retailing using robust optimization

Ministry of Education, Singapore under its Academic Research Funding Tier 1; Lee Kong Chian Fellowship; MPA Research Fellowshi

Manual small incision cataract surgery (MSICS) with posterior chamber intraocular lens versus extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens for age-related cataract.

BACKGROUND: Age-related cataract is the opacification of the lens, which occurs as a result of denaturation of lens proteins. Age-related cataract remains the leading cause of blindness globally, except in the most developed countries. A key question is what is the best way of removing the lens, especially in lower income settings. OBJECTIVES: To compare two different techniques of lens removal in cataract surgery: manual small incision surgery (MSICS) and extracapsular cataract extraction (ECCE). SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to September 2014), EMBASE (January 1980 to September 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to September 2014), Web of Science Conference Proceedings Citation Index- Science (CPCI-S), (January 1990 to September 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 23 September 2014. SELECTION CRITERIA: We included randomised controlled trials (RCTs) only. Participants in the trials were people with age-related cataract. We included trials where MSICS with a posterior chamber intraocular lens (IOL) implant was compared to ECCE with a posterior chamber IOL implant. DATA COLLECTION AND ANALYSIS: Data were collected independently by two authors. We aimed to collect data on presenting visual acuity 6/12 or better and best-corrected visual acuity of less than 6/60 at three months and one year after surgery. Other outcomes included intraoperative complications, long-term complications (one year or more after surgery), quality of life, and cost-effectiveness. There were not enough data available from the included trials to perform a meta-analysis. MAIN RESULTS: Three trials randomly allocating people with age-related cataract to MSICS or ECCE were included in this review (n = 953 participants). Two trials were conducted in India and one in Nepal. Trial methods, such as random allocation and allocation concealment, were not clearly described; in only one trial was an effort made to mask outcome assessors. The three studies reported follow-up six to eight weeks after surgery. In two studies, more participants in the MSICS groups achieved unaided visual acuity of 6/12 or 6/18 or better compared to the ECCE group, but overall not more than 50% of people achieved good functional vision in the two studies. 10/806 (1.2%) of people enrolled in two trials had a poor outcome after surgery (best-corrected vision less than 6/60) with no evidence of difference in risk between the two techniques (risk ratio (RR) 1.58, 95% confidence interval (CI) 0.45 to 5.55). Surgically induced astigmatism was more common with the ECCE procedure than MSICS in the two trials that reported this outcome. In one study there were more intra- and postoperative complications in the MSICS group. One study reported that the costs of the two procedures were similar. AUTHORS' CONCLUSIONS: There are no other studies from other countries other than India and Nepal and there are insufficient data on cost-effectiveness of each procedure. Better evidence is needed before any change may be implemented. Future studies need to have longer-term follow-up and be conducted to minimize biases revealed in this review with a larger sample size to allow examination of adverse events

Caregivers’ Falls Concern For Older Persons In The Singapore Community

This paper discusses the prevalence of caregivers’ concern, its impact on fall prevention strategies, falls risk awareness among older persons, clinical points and study potential. Older persons suffering from fall-related psychological concerns such as fear of falling has been well established in previous research, however little is known about caregivers’ falls concern in its relationship with the risk of older persons falling. In Singapore, families are regarded as the fundamental support system for older people. The potential influence of caregivers’ concern on the outcome of fall prevention strategies and falls risk awareness of older persons is expected given their significant involvement in the older persons’ care. However, it is difficult to accurately appreciate the impact of caregivers’ falls concern on the risk of falls among older persons in the local community given the Singaporean cultural differences and the dearth of Singaporean research on caregiver’s concern. It is promulgated in this paper that further research should address the impact of caregivers’ falls concern on fall-related issues associated with caring for an older person at risk of falling

Investigating the psychometric properties of the carers’ fall concern instrument to measure carers’ concern for older people at risk of falling at home: A cross-sectional study

© 2020 John Wiley & Sons Ltd Aims: This study aimed to investigate the psychometric properties of the Carers’ Fall Concern Instrument (CFC-I) for measuring carers’ concern for older people (care recipients) at risk of falling. Background: Family carers are crucial in preventing older people from falling at home. Their concerns for older people at risk of falling have severe implications on carers’ psychological well-being and ability to prevent falls. However, there is no validated instrument measuring this concern. Methods: A cross-sectional study was used to examine the validity and reliability of the CFC-I. Carers looking after older people living at home completed the 17-item CFC-I and provided information about their care arrangements and the older people\u27s fall history. Construct validity was tested using exploratory factor analysis and hypothesis testing. Internal consistency was determined by calculating Cronbach\u27s alpha coefficient. Results: 143 carers completed the survey either by face-to-face or by online. After deleting one item with an item-total correlation of below 0.3, the remaining 16-item CFC-I reported a Cronbach alpha of 0.93. Construct validity was supported by strong item-total correlations (0.51–0.76), mean inter-item correlations (0.47) and factor loadings (0.557–0.809). Factor analysis revealed three factors that include concerns about care recipients’ health and function, living environment and carers’ perception of fall and fall risk. The 16-item CFC-I can discriminate between carers of older people with and without recurrent (fallen 3/ more times) falls. Conclusion: The 16-item CFC-I is a valid and reliable scale for measuring carers’ concern for the older people\u27s risk of falling. Future analysis of test–retest and inter-rater reliability of the instrument will further support its clinical use for carers. Implications for practice: The newly developed multi-item CFC-I can be used to quantify the carers’ level of fall concern and inform targeted interventions for carers when caring for older people who are at risk of falling

A study of stochastic network with concurrent resources occupancy

Ph.DDOCTOR OF PHILOSOPH

Factors associated with risk of falling among younger inpatients in a mental health setting—A systematic review

Aim: To synthesise evidence related to risk factors of falls among younger mental health inpatients age ≤ 65 years old. Background: Hospitalised patients with mental illness are at increased risk of falling. Specific risk factors for falls for younger inpatients are poorly understood. Design: Systematic review. Methods: Medline, CINAHL, APA PsycINFO, Scopus and Web of Science were searched for studies published in English till December 2022. The review followed the 2020 PRISMA checklist. Odds ratios and P values of significant risk fall factors and the frequency of factors related to circumstances of falls were extracted. Results: Nine studies were included and 95 risk factors, across seven categories were extracted. These categories included socio-demographic, fall-related factors, functional status, health and mental status, psychiatric diagnosis and assessment, medication, and staff related factors. Factors related to medication, health and mental status are most reported. Majority of the patients sustained minor or no injury from the fall and circumstances of fall vary across studies. Conclusion: Factors strongly associated with risk of falls were dizziness, use of psychotropics and antihypertensive drugs. A meta-analysis of risk factors was not possible due to different dependent variables studied, controlled confounding variables and control groups used. Relevance to clinical practice: Fall prevention is relevant to all patients in mental health settings. Approaches to fall risk assessment and management need to be better tailored to younger mental health patients in the psychiatric setting. Patient and public contribution: Patient or public contribution was not possible because of the study design

The effect of group interaction processes on performance in time-series extrapolation

Abstract: This study explores the ability of groups to forecast and establish judgmental confidence intervals in time series extrapolation. Thirty-six three-person groups were used to evaluate four different group interaction processes. In addition to staticized, nominal group technique and consensus processes, the study utilizes a modified consensus process, where a selected group member completes the task prior to group discussion and interaction. Using real life time series, subjects produced forecasts and related confidence intervals for six periods. Groups in the modified-consensus structuring process exhibited significantly greater forecast accuracy than all other experimental conditions ( p < 0.001). The superiority was most pronounced for series of high forecast difficulty. These results are discussed in relation to the contribution of the initial estimates as an anchor on which the modified-consensus group can focus