The societal economic impact of vision impairment in adults 40 years and above: findings from the National Eye Survey of Trinidad and Tobago.

BACKGROUND: Understanding and mitigating the societal economic impact of vision impairment (VI) is important for achieving the Sustainable Development Goals. AIM: To estimate the prevalent societal economic impact of presenting VI in Trinidad and Tobago using bottom-up cost and utilisation data from the 2014 National Eye Survey of Trinidad and Tobago. METHODS: We took a societal perspective to combine comprehensive, individual-level cost and utilisation data, with population-based prevalence estimates for VI, and additional data from a contemporaneous national eyecare system survey. We included direct (medical and non-medical) and indirect (productivity loss) costs, and intangible losses in total cost estimates, presented in 2014 Trinidad & Tobago (TT) dollars and UK sterling equivalent. We considered but excluded transfer payments and dead weight losses. Sensitivity analyses explored impact on total cost of parameter uncertainty and assumptions. RESULTS: Individual utilisation and cost data were available for 65.5% (n = 2792/4263) and 59.0% (n = 2516/4263) eligible participants aged ≥40 years, respectively. Participant mean age was 58.4(SD 11.8, range 40-103) years, 56.3% were female. We estimated total societal cost of VI in 2014 at UK£365,650,241 (TT$3,842,324,655), equivalent to £675 per capita (population ≥40 years). Loss of wellbeing accounted for 73.3%. Excluding this, the economic cost was UK£97,547,222 (TT$1,025,045,399), of which indirect costs accounted for 70.5%, followed by direct medical costs (17.9%), and direct non-medical costs (11.6%). CONCLUSION: This study provides a comprehensive estimate of the economic impact of vision loss in a Caribbean country, and highlights the extent to which affected individuals and their families bear the societal economic cost of vision impairment.

Mental health support across the sight loss pathway: a qualitative exploration of eye care patients, optometrists, and ECLOs.

BACKGROUND: The process of becoming visually impaired or blind is undoubtedly a highly emotional experience, requiring practical and psychological support. Information on mental health support provision in the UK across the sight-loss pathway, however, is largely unknown, especially amongst healthcare practitioners that are often sought after for advice: the referring optometrist and eye clinic liaison officer (ECLO). This study aims to ascertain the perceived accessibility and quality of mental health support across the sight-loss pathway. METHODS: Semi-structured individual interviews were conducted with patients with a diagnosed eye condition who had received care from a hospital eye service, referring optometrists, and ECLOs. Following interview transcription, results were synthesised in a narrative analysis. RESULTS: A total of 28 participants were included in the analysis, of which 17 were participants with various eye conditions, five were referring optometrists, and five were ECLOs. After analysis, three broad themes emerged: (1) The emotional trauma of diagnosis (2) Availability of mental health support; (3) The point where mental health support is most needed across the sight-loss pathway. Several patients reporting that they had received no offer of support nor were they signposted to any possible sources. Referring optometrists and ECLO's agreed. CONCLUSION: It is important that referring optometrists are aware of the need for mental health support services and can signpost to local support services including the third sector anytime during the referral process. Future large-scale, UK-wide research into referral practice and signposting for mental health support for patients is warranted, to identify how services can be improved in order to ensure that the wellbeing of patients is maintained.

Resonant X-ray photoelectron spectroscopy: identification of atomic contributions to valence states.

Valence electronic structure is crucial for understanding and predicting reactivity. Valence non-resonant X-ray photoelectron spectroscopy (NRXPS) provides a direct method for probing the overall valence electronic structure. However, it is often difficult to separate the varying contributions to NRXPS; for example, contributions of solutes in solvents or functional groups in complex molecules. In this work we show that valence resonant X-ray photoelectron spectroscopy (RXPS) is a vital tool for obtaining atomic contributions to valence states. We combine RXPS with NRXPS and density functional theory calculations to demonstrate the validity of using RXPS to identify atomic contributions for a range of solutes (both neutral and ionic) and solvents (both molecular solvents and ionic liquids). Furthermore, the one-electron picture of RXPS holds for all of the closed shell molecules/ions studied, although the situation for an open-shell metal complex is more complicated. The factors needed to obtain a strong RXPS signal are investigated in order to predict the types of systems RXPS will work best for; a balance of element electronegativity and bonding type is found to be important. Additionally, the dependence of RXPS spectra on both varying solvation environment and varying local-covalent bonding is probed. We find that RXPS is a promising fingerprint method for identifying species in solution, due to the spectral shape having a strong dependence on local-covalency but a weak dependence on the solvation environment.

A one-pot-one-reactant synthesis of platinum compounds at the nanoscale.

The preparation of inorganic nanomaterials with a desired structure and specific properties requires the ability to strictly control their size, shape and composition. A series of chemical reactions with platinum compounds carried out within the 1.5 nm wide channel of single-walled carbon nanotubes (SWNTs) have demonstrated the ability of SWNTs to act as both a very effective reaction vessel and a template for the formation of nanocrystals of platinum di-iodide and platinum di-sulphide, materials that are difficult to synthesise in the form of nanoparticles by traditional synthetic methods. The stepwise synthesis inside nanotubes has enabled the formation of Pt compounds to be monitored at each step of the reaction by aberration-corrected high resolution transmission electron microscopy (AC-HRTEM), verifying the atomic structures of the products, and by an innovative combination of fluorescence-detected X-ray absorption spectroscopy (FD-XAS) and Raman spectroscopy, monitoring the oxidation states of the platinum guest-compounds within the nanotube and the vibrational properties of the host-SWNT, respectively. This coupling of complementary spectroscopies reveals that electron transfer between the guest-compound and the host-SWNT can occur in either direction depending on the composition and structure of the guest. A new approach for nanoscale synthesis in nanotubes developed in this study utilises the versatile coordination chemistry of Pt which has enabled the insertion of the required chemical elements (e.g. metal and halogens or chalcogens) into the nanoreactor in the correct proportions for the controlled formation of PtI2 and PtS2 with the correct stoichiometry.

Pharmacist's review and outcomes: Treatment-enhancing contributions tallied, evaluated, and documented (PROTECTED-UK).

PURPOSE: The purpose was to describe clinical pharmacist interventions across a range of critical care units (CCUs) throughout the United Kingdom, to identify CCU medication error rate and prescription optimization, and to identify the type and impact of each intervention in the prevention of harm and improvement of patient therapy. MATERIALS AND METHODS: A prospective observational study was undertaken in 21 UK CCUs from November 5 to 18, 2012. A data collection web portal was designed where the specialist critical care pharmacist reported all interventions at their site. Each intervention was classified as medication error, optimization, or consult. In addition, a clinical impact scale was used to code the interventions. Interventions were scored as low impact, moderate impact, high impact, and life saving. The final coding was moderated by blinded independent multidisciplinary trialists. RESULTS: A total of 20517 prescriptions were reviewed with 3294 interventions recorded during the weekdays. This resulted in an overall intervention rate of 16.1%: 6.8% were classified as medication errors, 8.3% optimizations, and 1.0% consults. The interventions were classified as low impact (34.0%), moderate impact (46.7%), and high impact (19.3%); and 1 case was life saving. Almost three quarters of interventions were to optimize the effectiveness of and improve safety of pharmacotherapy. CONCLUSIONS: This observational study demonstrated that both medication error resolution and pharmacist-led optimization rates were substantial. Almost 1 in 6 prescriptions required an intervention from the clinical pharmacist. The error rate was slightly lower than an earlier UK prescribing error study (EQUIP). Two thirds of the interventions were of moderate to high impact.

Prevalence and causes of vision loss in Southeast Asia and Oceania: 1990-2010.

BACKGROUND: To assess prevalence and causes of vision impairment in Southeast Asia and Oceania in 1990 and 2010. METHODS: Based on a systematic review of medical literature, prevalence of moderate and severe vision impairment (MSVI; presenting visual acuity <6/18 but ≥3/60 in the better eye) and blindness (presenting visual acuity <3/60) was estimated for 1990 and 2010. RESULTS: In Oceania, the age-standardised prevalence of blindness and MSVI did not decrease significantly (1.3% to 0.8% and 6.6% to 5.1%) respectively, but in Southeast Asia, blindness decreased significantly from 1.4% to 0.8%, a 43% decrease. There were significantly more women blind (2.18 million) compared with men (1.28 million) in the Southeast Asian population in 2010, but no significant gender differences in MSVI in either subregion. Cataract was the most frequent cause of blindness in Southeast Asia and Oceania in 1990 and 2010. Uncorrected refractive error, followed by cataract, macular degeneration, glaucoma and diabetic retinopathy were the most common causes for MSVI in 1990 and 2010. With the increasing size of the older population, there have been relatively small increases in the number of blind (2%), and with MSVI (14%) in Southeast Asia, whereas increases have been greater in Oceania of 14% for blindness and of 31% for MSVI. CONCLUSIONS: The prevalence of blindness has reduced significantly from 1990 to 2010, with moderate but non-significant lowering of MSVI. Cataract and uncorrected refractive error are the main causes of vision impairment and blindness; cataract continues as the main cause of blindness, but at lower proportions.

Gastrocnemius flap reconstruction of soft-tissue defects following infected total knee replacement.

A soft-tissue defect over an infected total knee replacement (TKR) presents a difficult technical problem that can be treated with a gastrocnemius flap, which is rotated over the defect during the first-stage of a revision procedure. This facilitates wound healing and the safe introduction of a prosthesis at the second stage. We describe the outcome at a mean follow-up of 4.5 years (1 to 10) in 24 patients with an infected TKR who underwent this procedure. A total of 22 (92%) eventually obtained a satisfactory result. The mean Knee Society score improved from 53 pre-operatively to 103 at the latest follow-up (p < 0.001). The mean Western Ontario and McMaster Universities osteoarthritis index and Short-Form 12 score also improved significantly (p < 0.001). This form of treatment can be used reliably and safely to treat many of these complex cases where control of infection, retention of the components and acceptable functional recovery are the primary goals.

Outcomes and complications of total hip replacement in super-obese patients.

The purpose of this study was to examine the complications and outcomes of total hip replacement (THR) in super-obese patients (body mass index (BMI) > 50 kg/m(2)) compared with class I obese (BMI 30 to 34.9 kg/m(2)) and normal-weight patients (BMI 18.5 to 24.9 kg/m(2)), as defined by the World Health Organization. A total of 39 THRs were performed in 30 super-obese patients with a mean age of 53 years (31 to 72), who were followed for a mean of 4.2 years (2.0 to 11.7). This group was matched with two cohorts of normal-weight and class I obese patients, each comprising 39 THRs in 39 patients. Statistical analysis was performed to determine differences among these groups with respect to complications and satisfaction based on the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, the Harris hip score (HHS) and the Short-Form (SF)-12 questionnaire. Super-obese patients experienced significantly longer hospital stays and higher rates of major complications and readmissions than normal-weight and class I obese patients. Although super-obese patients demonstrated reduced pre-operative and post-operative satisfaction scores, there was no significant difference in improvement, or change in the score, with respect to HHS or the WOMAC osteoarthritis index. Super-obese patients obtain similar satisfaction outcomes as class I obese and normal-weight patients with respect to improvement in their scores. However, they experience a significant increase in length of hospital stay and major complication and readmission rates.

Digital tomosynthesis: a new future for breast imaging?

The aim of this article is to review the major limitations in current mammography and to describe how these may be addressed by digital breast tomosynthesis (DBT). DBT is a novel imaging technology in which an x-ray fan beam sweeps in an arc across the breast, producing tomographic images and enabling the production of volumetric, three-dimensional (3D) data. It can reduce tissue overlap encountered in conventional two-dimensional (2D) mammography, and thus has the potential to improve detection of breast cancer, reduce the suspicious presentations of normal tissues, and facilitate accurate differentiation of lesion types. This paper reviews the latest studies of this new technology. Issues including diagnostic efficacy, reading time, radiation dose, and level of compression; cost and new innovations are considered.

Shared care of patients with ocular hypertension in the Community and Hospital Allied Network Glaucoma Evaluation Scheme (CHANGES).

AIMS: The Community and Hospital Allied Network Glaucoma Evaluation Scheme (CHANGES) used accredited community-based optometrists with a special interest (OSIs) in glaucoma to monitor ocular hypertensive (OHT) patients under virtual supervision of the Hospital Glaucoma Service (HGS). The purpose of this paper was to report the outcomes of the first completed community-based visit. METHODS: Eligible patients underwent a glaucoma consultant-led clinical examination before transfer to CHANGES. Individualised intraocular pressure (IOP) and follow-up time interval targets were set for each patient. OSIs used applanation tonometry, slit-lamp biomicroscopy, automated visual field testing and digital optic disc photography. The hospital-based glaucoma team evaluated the data virtually. Patients were referred back to the HGS according to specific criteria. RESULTS: One hundred and sixty eight OHT patients were invited to attend their first OSI appointment. Of these, 144 attended their appointment (attendance rate 85.7%). Outcomes of 130 patients with complete data sets are reported. Sixteen patients (12.3%) were referred back to the HGS due to IOP above target, new visual field defects and/or optic nerve changes. The glaucoma consultant retained eight patients (6.1%) within the HGS on the basis of definite or probable glaucomatous conversion. CONCLUSIONS: CHANGES freed up capacity within a busy HGS. However, improvements need to be made regarding non-attendance rates in the community. The relatively high one-year definite or probable conversion rate emphasises the importance of the comprehensive review of OHT patients and of hospital-led virtual supervision to maintain patient safety.

Does morbid obesity affect the outcome of total hip replacement?: an analysis of 3290 THRs.

We evaluated the outcome of primary total hip replacement (THR) in 3290 patients with the primary diagnosis of osteoarthritis at a minimum follow-up of two years. They were stratified into categories of body mass index (BMI) based on the World Health Organisation classification of obesity. Statistical analysis was carried out to determine if there was a difference in the post-operative Western Ontario and McMaster Universities osteoarthritis index, the Harris hip score and the Short-Form-12 outcome based on the BMI. While the pre- and post-operative scores were lower for the group classified as morbidly obese, the overall change in outcome scores suggested an equal if not greater improvement compared with the non-morbidly obese patients. The overall survivorship and rate of complications were similar in the BMI groups although there was a slightly higher rate of revision for sepsis in the morbidly obese group. Morbid obesity does not affect the post-operative outcome after THR, with the possible exception of a marginally increased rate of infection. Therefore withholding surgery based on the BMI is not justified.

Delamination wear on two retrieved polyethylene inserts after gamma sterilization in nitrogen.

Two self-aligning mobile bearing knee replacements (SAL-1) with gamma-in-nitrogen sterilized polyethylene inserts were revised due to instability after 6.3 years and after 14.2 years in vivo in two patients. The predominant damage features were burnishing, cracking, and delamination and were observed on the proximal bearing surface of the retrieved polyethylene inserts. This suggested an association with sub-surface fatigue, perhaps initiated by in vivo oxidative degradation which was confirmed by developing a sub-surface white band in one insert. The damage features observed on the distal bearing surface of the polyethylene inserts suggested both an adhesive wear mechanism and an abrasive wear mechanism. The titanium-nitrite coated, titanium-alloy tibial tray was severely worn in one case and possibly contributed to third-body abrasive wear at the distal surface interface. We suggest to carefully follow-up patients who received this type of mobile bearing knee system.

Ethnicity and ocular imaging.

There exist ethnic differences in the prevalence of many ocular diseases. The ocular structures affected by these diseases can be imaged with devices that have increased in complexity over recent years. The purpose of this review is to explore what we mean by the term 'ethnicity' and what we know of ethnic differences in the structures of the eye that are commonly imaged. Finally, the implications of these ethnic differences are discussed in relation to the detection and monitoring of ocular disease that involves imaging instruments.

Biochemical comparisons of osteoarthritic human synovial fluid with calf sera used in knee simulator wear testing.

Osteoarthritic human synovial fluid was obtained from the knees of 20 patients and was compared with four different calf sera solutions frequently used as lubricants in knee simulator wear testing. Assuming that the fluid after arthroplasty was the same as the fluid in patients with osteoarthritis, the total protein concentration, protein constituent fractions, osmolality, trace element concentrations, and the thermal stability obtained via differential scanning calorimetry were determined. Human synovial fluid, with an average total protein concentration of 34 g/L, was significantly different from all undiluted calf sera. However, alpha-calf serum and iron-supplemented alpha-calf serum were closest in protein constituent fractions (albumin, alpha-1-globulin, alpha-2-globulin, ss-globulin, and gamma-globulin) to human synovial fluid. Diluting calf sera with low-ion distilled water to a total protein concentration of 17 g/L (as recommended by ISO 14243) produced non-clinically relevant total protein concentration and osmolality levels. Performing the same dilution of iron-supplemented alpha-calf serum with phosphate-buffered saline solution and 1.5 g/L hyaluronic acid produced an artificial lubricant with both a clinically relevant level of osmolality and clinically relevant thermal stability as seen in human synovial fluid from patients with osteoarthritis. The present study suggested that alpha-calf serum, phosphate-buffered saline solution and hyaluronic acid were essential constituents of an artificial lubricant to mimic the major biochemical properties of human synovial fluid for simulator wear testing of total knee replacements.

Randomised controlled trial comparing early migration of two collarless polished cemented stems using radiostereometric analysis.

This was a safety study where the hypothesis was that the newer-design CPCS femoral stem would demonstrate similar early clinical results and micromovement to the well-established Exeter stem. Both are collarless, tapered, polished cemented stems, the only difference being a slight lateral to medial taper with the CPCS stem. A total of 34 patients were enrolled in a single-blinded randomised controlled trial in which 17 patients received a dedicated radiostereometric CPCS stem and 17 a radiostereometric Exeter stem. No difference was found in any of the outcome measures pre-operatively or post-operatively between groups. At two years, the mean subsidence for the CPCS stem was nearly half that seen for the Exeter stem (0.77 mm (-0.943 to 1.77) and 1.25 mm (0.719 to 1.625), respectively; p = 0.032). In contrast, the mean internal rotation of the CPCS stem was approximately twice that of the Exeter (1.61 degrees (-1.07 degrees to 4.33 degrees ) and 0.59 degrees (0.97 degrees to 1.64 degrees ), respectively; p = 0.048). Other migration patterns were not significantly different between the stems. The subtle differences in designs may explain the different patterns of migration. Comparable migration with the Exeter stem suggests that the CPCS design will perform well in the long term.

Can a community optometrist-based referral refinement scheme reduce false-positive glaucoma hospital referrals without compromising quality of care? The community and hospital allied network glaucoma evaluation scheme (CHANGES).

BACKGROUND/AIMS: To describe the design, activity, and quality of the referral refinement phase of a novel glaucoma shared-care scheme. METHODS: Eight Optometrists with a Specialist Interest in glaucoma (OSI) were trained to perform a community-based comprehensive glaucoma evaluation of low-risk glaucoma hospital referrals (only one/none of the following factors noted for either eye: abnormal optic disc, abnormal visual field, abnormal intraocular pressure (IOP; 22-28 mmHg or IOP asymmetry)) using equipment standardized to that of the hospital glaucoma service. RESULTS: One hundred and thirty-eight (27%) of a total of 512 glaucoma-related referrals were deemed 'low risk'. Their choice of OSI discharged 40 (35%). The consultant agreed (virtually) with the decision to discharge with 28 (70%) and disagreed with 12 (30%). Comparing findings between OSI and consultant for 99 referred patients, sensitivity, specificity, and negative predictive values for a suspicious optic disc were 78, 61, and 79%, respectively. For an IOP of >21 mmHg, they were 74, 85, and 90%, respectively. For an occludable anterior chamber angle (Van Herick's versus gonioscopy), they were 69, 88, and 94%, respectively. CONCLUSION: This referral refinement process can reduce numbers of false-positive referrals attending the hospital glaucoma service while retaining a relatively high level of examination quality.

The morphology of the optic nerve head in the Singaporean Chinese population (the Tanjong Pagar study): part 1--Optic nerve head morphology.

BACKGROUND/AIMS: To investigate the correlation between optic disc parameters and their association with demographic variables in a Chinese population. METHODS: Disc data were obtained from 929 subjects aged > or = 40 years from the Tanjong Pagar glaucoma survey of Singapore, using a novel planimetric method of sequential stereo-photographs. Biometric data (refractive error, keratometry, axial length, anterior chamber depth, lens thickness) were used to calculate ocular magnification. Camera magnification was quantified with a model eye. A "normal" dataset of 622 subjects was generated by exclusion of subjects with abnormal results on psychophysical testing, an occludable angle or an intraocular pressure > 97.5th percentile in either eye. RESULTS: Median disc area (DA), cup area (CA), and rim area (RA) were 2.09 (range 1.28-4.01) mm2, 0.69 (0.01-1.90) mm2 and 1.38 (0.82-2.50) mm2, respectively. There was strong evidence of an association between DA and RA (Spearman's rho 0.624, p<0.001). DA and RA were significantly greater in men (median DA = 2.20; range 1.30-3.56; median RA, 1.45; range 0.85-2.30) than women (median DA, 2.00; range 1.28-4.01; median RA, 1.36; range 0.82-2.49, p<0.001). DA increased with age (Spearman's rho 0.115, p = 0.004), while RA was unrelated (rho -0.041; p = 0.308). CONCLUSIONS: The morphometric characteristics of optic discs in Chinese Singaporeans are very similar to those described in other groups, with the temporal sector rim having the smallest area. Disc and rim areas vary with sex (men > women). Disc area (but not that of the rim) increases with age.