Clinacanthus nutans extract lowers periodontal inflammation under high-glucose conditions via inhibiting NF-κB signaling pathway.

Periodontal disease is more prevalent in patients with diabetes, and it has a negative impact on their quality of life. Inhibiting the infection and inflammation processes that cause periodontal disease can reduce the severity of the disease and chances of serious complications. In this study, we aimed to demonstrate the effectiveness of Clinacanthus nutans extract in reducing the inflammation in gingival fibroblast cells induced by Porphyromonas gingivalis lipopolysaccharide (LPS). Stimulation with LPS under high-glucose conditions led to increased inflammation compared to low-glucose conditions. Treatment of C. nutans extract significantly reduced the expression of these pro-inflammatory cytokines and chemokines. At a concentration of 50 µg/mL, it reduced the relative expression of IL6, IL8, and CXCL10 to 0.51 ± 0.09, 0.6 ± 0.19, and 0.09 ± 0.02, respectively, compared to the non-treatment control, accompanied by a decrease in secreted protein as measured by ELISA. Additionally, application of C. nutans extract markedly suppressed the NF-κB signaling pathway by reducing the phosphorylated form of IκBα, NF-κB p65, and nuclear translocation of NF-κB, along with a decrease in COX2, a key mediator in the inflammatory pathway. Furthermore, analysis of RNA sequencing data indicated that the extract clearly reversed the gene expression changes induced by LPS. This was particularly true for the signaling mediators and inflammatory genes in response to NF-κB, JAK/STAT, and TNF signaling pathways. Our finding highlights the potential of C. nutans extract to alleviate inflammation and suggests its potential as a treatment for periodontal disease in patients with diabetes.

Disruption of the pro-oncogenic c-RAF-PDE8A complex represents a differentiated approach to treating KRAS-c-RAF dependent PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is considered the third leading cause of cancer mortality in the western world, offering advanced stage patients with few viable treatment options. Consequently, there remains an urgent unmet need to develop novel therapeutic strategies that can effectively inhibit pro-oncogenic molecular targets underpinning PDACs pathogenesis and progression. One such target is c-RAF, a downstream effector of RAS that is considered essential for the oncogenic growth and survival of mutant RAS-driven cancers (including KRASMT PDAC). Herein, we demonstrate how a novel cell-penetrating peptide disruptor (DRx-170) of the c-RAF-PDE8A protein-protein interaction (PPI) represents a differentiated approach to exploiting the c-RAF-cAMP/PKA signaling axes and treating KRAS-c-RAF dependent PDAC. Through disrupting the c-RAF-PDE8A protein complex, DRx-170 promotes the inactivation of c-RAF through an allosteric mechanism, dependent upon inactivating PKA phosphorylation. DRx-170 inhibits cell proliferation, adhesion and migration of a KRASMT PDAC cell line (PANC1), independent of ERK1/2 activity. Moreover, combining DRx-170 with afatinib significantly enhances PANC1 growth inhibition in both 2D and 3D cellular models. DRx-170 sensitivity appears to correlate with c-RAF dependency. This proof-of-concept study supports the development of DRx-170 as a novel and differentiated strategy for targeting c-RAF activity in KRAS-c-RAF dependent PDAC.

Cancer: Phosphodiesterase type 4C (PDE4C), the forgotten subfamily as a therapeutic target.

Phosphodiesterase type 4 (PDE4) enzymes specifically hydrolyse cAMP in many cell signalling systems that are transduced by hormones and other primary messengers. The physiological function of the four PDE4 subfamilies (A, B, C and D) are numerous and varied due to the differentially localised plethora of isoforms that can be detected in cardiovascular, CNS and immune systems. Of the four subfamilies, least is known about PDE4C probably due to its restricted distribution pattern, scarcity of selective inhibitors and the lack of developed research tools. Here, for the first time, we chart the discovery of PDE4C, describe its regulation and highlight cancers where future development of PDE4C selective small molecules may have potential.

A head-to-head comparison of 16 cataract surgery outcome questionnaires.

PURPOSE: To investigate the responsiveness of 16 questionnaires used in cataract surgery outcomes. DESIGN: Prospective, observational study. PARTICIPANTS: Patients at the Ophthalmology Eye Clinic, Flinders Medical Centre, Adelaide, Australia, and 1 matched eye clinic in Sweden. METHODS: Sixteen Rasch-scaled cataract surgery questionnaires were completed before and 6 months after surgery. These were: the Cataract Symptom Scale, 6 versions of the National Eye Institute Visual Function Questionnaire, the Quality of Life and Vision Function Questionnaire, the Cataract TyPE Specification, the Visual Activities Questionnaire, the Visual Disability Assessment (VDA), the Visual Function and Quality of Life questionnaire, the Visual Function Index, Catquest-9SF, the Visual Symptoms and Quality of Life questionnaire, and the Cataract Outcomes Questionnaire. Responsiveness was calculated with the effect size (ES) statistic (change in questionnaire score divided by pooled standard deviation of the preoperative and postoperative scores). MAIN OUTCOME MEASURES: Questionnaire responsiveness to cataract surgery (ability to detect clinically important change). RESULTS: All 16 questionnaires and their subscales were responsive to cataract surgery, with visual functioning scales being more responsive than socioemotional scales and some subscales being less responsive. The largest ES was for the Catquest-9SF (1.45; 95% confidence interval [CI], 1.22-1.67), which was the only instrument with a mean and 95% CI of more than 1.0 (very large ES). Three measures had very large ESs and 95% CIs of more than 0.80 (large ES): the VDA (activity limitations and subscale) and the Cataract Outcomes Questionnaire, although their 95% CIs overlapped with a number of other instruments. CONCLUSIONS: The Catquest-9SF is short and highly responsive to cataract surgery, and so is ideal for measuring visual functioning outcomes. Other instruments may be preferred to measure different constructs. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Improvements in visual ability with first-eye, second-eye, and bilateral cataract surgery measured with the visual symptoms and quality of life questionnaire.

PURPOSE: To determine whether the Visual Symptoms and Quality of Life Questionnaire (VSQ), which was developed to be sensitive to second-eye cataract surgery, has satisfactory psychometric properties and, if so, to examine first-eye, second-eye, and bilateral cataract surgery outcomes. SETTING: Ophthalmology Clinic, Flinders Medical Centre, Adelaide, Australia. DESIGN: Cohort study. METHODS: The 26-item VSQ was self-administered by cataract patients before and after cataract surgery and by those on the cataract surgery waiting list. The VSQ was revised by Rasch analysis using preoperative questionnaire data. The surgical outcome measures were logMAR visual acuities and the Rasch-refined VSQ. RESULTS: The VSQ was self-administered by 92 patients before and after surgery (25 first eye, 38 second eye, and 29 bilateral) and by 147 on the waiting list. The preoperative visual acuity (surgical eye) was similar across groups. Cataract surgery improved visual acuities in all groups; the mean better-seeing eye visual acuity was significantly better (by 2 lines) in second and bilateral surgery patients than in first-eye surgery patients. Preoperative visual disability was significantly higher in patients awaiting cataract surgery in both eyes than in those awaiting second-eye surgery. Postoperatively, visual disability decreased significantly in all groups (first eye, 1.66 logits; second eye, 1.52 logits; bilateral, 2.58 logits). However, a floor effect limited the measurement of visual disability after cataract surgery. CONCLUSIONS: The revised visual disability scale of the VSQ measured a reduction in visual disability after first, second, and bilateral cataract surgery. However, the VSQ could not measure lower levels of visual disability, suggesting better questionnaires are required. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Multiplicative rating scales do not enable measurement of vision-related quality of life.

PURPOSE: Many questionnaires for the measurement of visual impairment exist. One, the Houston Vision Assessment Test (HVAT), takes a different approach: the patient is asked to rate overall impairment and the proportion attributed to vision, then through multiplication the visual and non-visual (physical) impairments are calculated. The purpose of this study was to determine whether the scores derived from this approach can be considered to be measures. METHODS: The participants were 193 cataract patients awaiting surgery (mean age 74.1 ± 9.8 years, 54 per cent female and 53.6 per cent were awaiting first eye surgery), who self-administered the HVAT, which consists of 10 questions, whereby impairment on each activity and the proportion attributable to vision is rated. Therefore, total, visual and physical impairments are calculated. For each question, multiplying the impairment (five response categories) by the proportion due to eyesight (five categories) gives 10 possible levels of visual impairment. Assessment of the multiplicative rating scales included frequency of category use and hierarchical ordering of response categories using category thresholds. Summary statistics of Rasch analysis were generated for the rating scale and overall questionnaire performance. RESULTS: In the multiplicative scale, higher response categories were under-utilised and thresholds were disordered, indicating that the categories did not function as intended. Some of the dysfunction arose from disordered thresholds in the 'proportion due to eyesight scale', but repairing this gave little improvement to the multiplicative scale. The ill-defined nature of the disordered categories precluded further repair by combining categories. Measurement precision, as indicated by person separation reliability, was poor (0.70). CONCLUSION: Rasch analysis demonstrated that the categories of the multiplied rating scale of the HVAT were not ordered, as the user would expect; this precludes measurement. This provides evidence against the use of multiplicative rating scales in quality-of-life questionnaires. It would be better to use a single rating scale for each construct of interest.

The impact of cataract surgery questionnaire: re-evaluation using Rasch analysis.

PURPOSE: The Impact of Cataract Surgery (ICS) questionnaire was designed to assess cataract surgery outcomes. The aim of this study was to describe the psychometric properties of the ICS questionnaire using the Rasch model in a cataract population. METHODS: Ninety-one patients waiting to undergo cataract surgery in the first or second eye at the Flinders Medical Centre, Adelaide, South Australia self-administered the four-item ICS questionnaire. Rasch analysis was performed to assess behaviour of response categories, ability to differentiate between participants' visual abilities (person separation; minimum acceptable 2.0), if items measure a single underlying construct [i.e. unidimensionality assessed by fit statistics and further by principal components analysis (PCA)] and matching of item difficulty to participant ability (targeting; ideal < 0.5 logits). Adequate person separation was defined as basic requirement for a measure, failing which further assessment such as PCA was not performed. RESULTS: The four-item ICS questionnaire did not meet the required measurement properties (person separation zero). Response categories did not behave as intended, requiring the collapsing of categories for one item (read ordinary newspaper-size print). One item misfit (estimating distance) indicating that it was not measuring the same construct as other items. However, person separation failed to improve following the deletion of this item. Targeting was -0.46 logits, indicating that the item difficulty was well suited to the visual abilities of the participants. CONCLUSION: In its present form, the ICS is unsuitable for visual disability assessment in patients awaiting cataract surgery. Other, better visual function questionnaires are available and preferred.

Measuring outcomes of cataract surgery using the Visual Function Index-14.

PURPOSE: To determine which version of the Visual Function Index-14 (VF-14) most precisely measured cataract surgery outcomes, rescale the VF-14 using Rasch analysis, and create a short-form version for comparison. SETTING: Flinders Medical Centre, Adelaide, South Australia, Australia. METHODS: In this cohort study incorporating questionnaire development, participants were drawn from the cataract surgery waiting list at Flinders Medical Centre. There were 2 cohorts: a preoperative cohort used for questionnaire development and an outcomes cohort. All patients had cataract surgery by phacoemulsification with intraocular lens implantation. Rasch analysis was used to refine the VF-14 into valid long-form (VF-11R) and short-form (VF-8R) versions. The ability of 8 versions (original; 2 proposed versions; 5 previously proposed versions) of the VF-14 to discriminate cataract surgery outcomes was compared with that of the standard VF-14 using the relative precision method. RESULTS: The preoperative cohort comprised 210 patients and the outcomes cohort, 51 patients. Large gains in visual functioning occurred with cataract surgery, and these were detectable with all versions of the VF-14. The largest gain in precision, 125% (relative precision. 2.25), occurred for VF-8R. Short forms that were not Rasch scaled showed gains in precision, from 23% to 80%. The VF-8R also showed the largest gains in precision in 2 subgroups: with ocular comorbidity (relative precision, 2.14) and without ocular comorbidity (relative precision, 2.48). CONCLUSIONS: Results show an unequivocal advantage to using Rasch-scaled scores for assessing cataract surgery outcomes. The 8-item, Rasch-scaled VF-8R appears ideally suited for measuring cataract surgery outcomes given its high precision and short test time. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

The refractive status and vision profile: Rasch analysis of subscale validity.

PURPOSE: To determine whether the eight subscales of the Refractive Status and Vision Profile (RSVP) questionnaire provide valid measurement. METHODS: Two hundred patients, recruited from a refractive surgery clinic and general optometric practice, self-administered the 42-item RSVP questionnaire. Psychometric properties investigated included measurement of a single construct (unidimensionality), item fit to construct, measurement precision (represented by person separation), targeting of item difficulty to patient's quality of life (QOL), and differential item functioning. RESULTS: Only two subscales ("concern" and "driving") showed adequate person separation, indicating that they could discriminate patients' QOL. However, both demonstrated poor targeting (7.02 logits for "driving" and 1.11 logits for "concern"). One-third of items in each subscale suffered from differential item functioning. CONCLUSIONS: None of the RSVP subscales are valid for assessment of QOL in patients with refractive error, thereby indicating the RSVP should be considered as a single questionnaire without subscales.

Activities of Daily Vision Scale: what do the subscales measure?

PURPOSE: Previous Rasch analysis of the Activities of Daily Vision Scale (ADVS) did not address psychometric properties of its subscales or provide detailed assessment of dimensionality (whether the ADVS measures one or multiple constructs). This study was designed to examine these properties. METHODS: Two hundred thirty-two participants (mean age, 74.2 years) awaiting cataract surgery self-administered the ADVS. Rasch analysis was used to assess the ADVS and its five subscales for unidimensionality (by principal components analysis, [PCA]), precision by person separation (discrimination between strata of participant ability), and targeting (matching of item difficulty to participant ability). Adequate person separation (minimum acceptable value, 2.0) is the fundamental requirement for measurement. RESULTS: Only the near vision subscale had adequate measurement properties (person separation, 2.30). The entire ADVS showed a misfit to the Rasch model and lacked unidimensionality. PCA confirmed the presence of two additional traits-driving and glare disability-but neither possessed adequate person separation when assessed individually. Deleting these traits restored unidimensionality, but additional items misfit, necessitating item reduction. Finally, an eight-item ADVS-Near Vision Scale showed good fit and unidimensionality. Its contents were identical with the original near vision subscale. Targeting was suboptimal (2.30 logits). CONCLUSIONS: Only one subscale, near vision, met the criteria for measurement. The revised eight-item ADVS-Near Vision subscale is a unidimensional measure of visual disability in cataract patients with mild visual disability. However, it is limited by measurement of near visual ability only. For more comprehensive measurement of visual disability, other questionnaires such as Catquest-9SF are preferable for cataract surgery outcomes assessment.

McMonnies questionnaire: enhancing screening for dry eye syndromes with Rasch analysis.

PURPOSE: To determine, by using Rasch analysis, whether the McMonnies questionnaire possesses the properties of a measure and whether screening for dry eye syndromes (DESs) can be enhanced by using different scoring approaches. METHODS: The questionnaire was self-administered by 43 female Sjögren syndrome patients (>45 years) recruited from a specialized rheumatology clinic and 140 age-matched control subjects. Data were scaled by using Rasch analysis and were assessed for response category behavior and ability to reliably discriminate between severity of the participant's dry eye symptoms (i.e., person separation reliability; minimum acceptable value, 0.80). Standard summary statistics of screening performance were calculated for raw and Rasch-scaled scores from receiver-operating characteristic analysis including area under the curve (AUC). Best predictors (i.e., questions) from a discriminant analysis were used to calculate a discriminant function for both Rasch-scaled and raw scores. RESULTS: Response categories were not used as intended, necessitating a collapse of categories. Person separation reliability was inadequate (0.75). A Rasch-scaled discriminant cutoff score of -2.29 logits from seven items provided an AUC of 0.99 with 95% sensitivity. However, discriminant raw score from modification in the scoring of a question (e.g., use of medications), used as one rather than multiple questions, provided an AUC (0.97) that was not significantly different (z = 1.11, P = 0.27), with 98% sensitivity, and required only two questions. CONCLUSIONS: In this population, the McMonnies questionnaire does not function as a measure. However, various scoring methods can be used to efficiently screen for DES.

Visual disability assessment: valid measurement of activity limitation and mobility in cataract patients.

AIM: The Visual Disability Assessment (VDA), a questionnaire for measuring the impact of cataract on visual functioning, was developed using classical test theory. Since this approach is limited, our aim was to further investigate the psychometric properties of the VDA using Rasch analysis. METHODS: 613 patients from the Flinders Medical Centre cataract surgery self-administered the VDA. Psychometric properties investigated for the overall VDA and each subscale included: measurement of a single construct (unidimensionality), item fit to the construct, reliable discrimination between strata of patient ability (person separation) and targeting of item difficulty to person ability. RESULTS: The VDA discriminated five strata of patient ability. However, seven mobility items constituted a second dimension and formed a valid separate scale. Sequestration of these items resulted in a unidimensional 11-item measure of activity limitation. Both the mobility and activity limitation scales had acceptable person separation and neither contained misfitting items. Targeting was suboptimal for mobility (-2.12 logits) but good for activity limitation (-0.72). The subscales also satisfied the requirements of the Rasch measurement model. CONCLUSIONS: The Rasch-scaled VDA effectively measures two separate constructs: mobility and activity limitation (with two subscales). Its good psychometric properties make it suitable for measuring cataract surgery outcomes.

Catquest questionnaire: re-validation in an Australian cataract population.

BACKGROUND: The Catquest questionnaire was developed using traditional methodology to enable cataract surgery outcomes assessment in European countries. Recently, it has been validated using Rasch analysis in a Swedish population resulting in the Catquest-9SF. The aim of the present study was to assess the performance of the Catquest and the Catquest-9SF questionnaires using Rasch analysis in Australian cataract patients. METHODS: A total of 217 cataract patients awaiting surgery at Flinders Medical Centre, Adelaide, South Australia self-administered the Catquest questionnaire. This is a 19-item instrument containing frequency, difficulty, symptoms and global rating items. Rasch analysis was undertaken to assess the unidimensionality (whether all the items are measuring a single underlying construct using principal components analysis or PCA), person separation (ability of the questionnaire to distinguish between strata of patient ability) and targeting of item difficulty to person ability. RESULTS: Similar to the previous validation study, the original Catquest questionnaire required revision because of misfit and multidimensionality necessitating removal of the frequency items. The revised version was similar to the Catquest-9SF although an extra driving item was a valid optional inclusion. The Catquest-9SF performed well in the Australian cohort satisfying all criteria for valid measurement including unidimensionality. However, targeting of item difficulty to person ability was marginally worse compared with the Swedish cataract population indicating the Australian cataract patients present for surgery at lower levels of visual disability. CONCLUSIONS: The Catquest-9SF is a reliable and valid measure of visual disability in the Australian cataract population.

Visual Activities Questionnaire: assessment of subscale validity for cataract surgery outcomes.

PURPOSE: To examine the psychometric properties of the Visual Activities Questionnaire (VAQ) and each of its subscales in a modern cataract population using Rasch analysis and if flawed, to revise the VAQ and create a valid measure that maximizes its measurement properties. SETTING: Flinders Eye Centre, Flinders Medical Centre, Adelaide, Australia. METHODS: Patients with cataract in 1 or both eyes drawn from the surgical waiting list were mailed the 33-item VAQ for self-administration. The following were examined for the entire questionnaire and each subscale: whether items measured a single construct (unidimensionality), the behavior of response categories, the ability to differentiate between patients' visual abilities (person separation), matching of item difficulty to participant ability (targeting), and whether items function similarly across subgroups of participants (differential item functioning [DIF]). RESULTS: The VAQ was completed by 561 patients. Response categories were used as intended. The VAQ discriminated the visual ability of the population (person separation, 4.88) but had suboptimum targeting, misfitting items, significant multidimensionality, DIF, and 4 dysfunctional subscales. Elimination of items causing multidimensionality resulted in a reduced 13-item VAQ that met all validity criteria for satisfactory instrument performance. Only 1 valid subscale (peripheral vision) could be preserved in the 13-item VAQ. CONCLUSIONS: The VAQ in its native form was multidimensional and contained subscales with poor psychometric properties. The revised unidimensional 13-item VAQ was more appropriate for application in cataract outcomes assessment. Ideally, more items should be included to improve the targeting of item difficulty to more able cataract patients.

Cataract symptom score questionnaire: Rasch revalidation.

PURPOSE: The 5-item Cataract Symptom Score (CSS) was developed using classical test theory to determine appropriate timing for cataract surgery, its outcomes, and whether the symptoms included bother cataract patients. The purpose of this study was to investigate the psychometric properties of the 5-item CSS using Rasch analysis. METHODS: Responses from 113 patients awaiting cataract surgery to the 5-item CSS (bothered by double or distorted vision, glare or halos, blurry vision, colors looking different and worsening of vision) were subjected to Rasch analysis. The use of response categories (threshold order), ability of CSS to discriminate between participants' severity of symptoms (person separation, recommended minimum value 2.0), matching of item difficulty to severity of symptoms (targeting), and ability of items to measure a single construct (unidimensionality) were investigated. RESULTS: Participants used the response categories as intended. However person separation (1.74) was inadequate, suggesting that the CSS could differentiate only between two groups of participants by their symptoms. Furthermore the CSS was poorly targeted for our population, as the majority of our participants were not bothered by symptoms in the CSS. All items fit the single construct, implying that the CSS is a unidimensional measure of cataract symptoms. CONCLUSIONS: The CSS is unable to discriminate people with cataract. This problem could be fixed by adding additional questions, but a superior approach may be to create an item bank of cataract symptoms questions, including those of the CSS, and utilize computer-adaptive testing for measurement.

Rasch analysis of visual function and quality of life questionnaires.

PURPOSE: To investigate the psychometric properties of the Visual Function (VF) and Quality of Life (QOL) questionnaires, using the Rasch measurement model. METHODS: Four hundred eighty-nine patients with cataract awaiting surgery, drawn from the surgical waiting list of the Flinders Medical Centre, Adelaide, South Australia, were mailed the VF and QOL questionnaires for self-administration. Rasch analysis was undertaken to assess the following properties: measurement of a single construct (i.e., unidimensionality by fit statistics and principal components analysis), discrimination between strata of participant ability (person separation, recommended minimum value 2.0), targeting of item difficulty to participant ability, and differential item functioning (DIF, whether items function similarly for different subgroups and notable DIF defined as >1.0 logit). RESULTS: The VF questionnaire fit the Rasch model showing good metric properties, including unidimensionality, and was free of notable DIF. The QOL questionnaire showed inadequate person separation, two misfitting items and significant multidimensionality (Eigenvalue of 2.3 for the first contrast), suggesting the presence of a separate subscale, self-care, but this was not valid because of inadequate person separation. Deleting these contrasting items from the QOL questionnaire removed multidimensionality and item misfit but did not improve person separation, indicating that it could not effectively discriminate between the participant's QOL. Both VF and QOL questionnaires demonstrated poor targeting (-2.22 and -3.26 logits, respectively), indicating that items were too easy and participants had higher QOL than that the items allowed for. Three items in the QOL questionnaire demonstrated notable DIF by age and systemic comorbidity. None of the subscales functioned optimally. CONCLUSIONS: The QOL questionnaire is not a valid measure of QOL. However, the VF questionnaire is a reliable and valid measure of visual disability in patients with cataract, and although targeting was suboptimal in a developed country, it may be optimal in a developing country as was originally intended.

Using Rasch analysis to revisit the validity of the Cataract TyPE Spec instrument for measuring cataract surgery outcomes.

PURPOSE: To assess the psychometric properties of the Cataract TyPE Specification (Spec) questionnaire using the Rasch model. SETTING: Flinders Medical Centre, Adelaide, Australia. METHODS: The 12-item Cataract TyPE Spec questionnaire was self-administered to patients drawn from the cataract surgery waiting list. The questionnaire and its 5 subscales were assessed for fit to the Rasch model. Response category performance, item-fit targeting, unidimensionality (using principal components analysis), and differential item functioning were assessed. A shortened version (11 items) was tested for criterion validity by determining correlation with a global rating of vision question. RESULTS: Two hundred ninety-four patients responded to the questionnaire. The response categories for each question functioned as intended. Person-separation reliability was high (0.90). Deletion of 1 misfitting item (nighttime driving) improved overall model fit. The principal components analysis of the residuals demonstrated unidimensionality for the 11-item Cataract TyPE Spec and 2 subscales. However, items were targeted to a less able population. Only 2 subscales (near vision and glare) were valid. There was a good statistically significant correlation between the Likert-scored global rating of vision and the Rasch-scaled Cataract TyPE Spec score (r = -0.66, P<.0001), suggesting good criterion validity. CONCLUSIONS: With minor modifications, the Cataract TyPE Spec questionnaire and its glare and near-vision subscales were good measures of visual functioning in the cataract patient. Additional items to suit the more able, including patients having second-eye surgery, could improve the measurement properties.

Rasch analysis of the quality of life and vision function questionnaire.

PURPOSE: The Quality of life and Vision Function Questionnaire (QOL-VFQ) was developed using classical test theory to assess outcomes of cataract surgery. The aim of this study was to examine the psychometric properties of this questionnaire using Rasch analysis in a cataract population. METHODS: The 17-item QOL-VFQ was self-administered to 389 patients waiting to undergo cataract surgery. The QOL-VFQ and its five subscales were assessed for fit to the Rasch model. Rasch analysis was used to estimate interval level measures of "visual ability" from ordinal scores for the QOL-VFQ and its five subscales. Unidimensionality, item fit, response category performance, and targeting of items to patients were assessed. RESULTS: The QOL-VFQ and its five subscales showed ordered category thresholds. Despite removal of two misfitting items the person separation reliability was high and the QOL-VFQ could distinguish among three strata of patient ability. However, there was suboptimal targeting of patient ability to item difficulty as most of the patients had higher levels of visual functioning. None of the subscales demonstrated acceptable psychometric properties. CONCLUSIONS: These results support the good overall functioning of the QOL-VFQ in patients with cataract. However, adding more items, that suit the more able patients including those who are awaiting cataract surgery in the fellow eye, will help improve the targeting.

Guttman scale analysis of the distance vision scale.

PURPOSE: The Distance Vision Scale (DVS) is a self-assessment of visual acuity (VA). Like VA testing in which letter reading becomes progressively difficult through the test, DVS questions have a hierarchy of difficulty (Guttman scale). The aims were to determine whether the DVS fulfills Guttman scaling criteria and to test the relationship between DVS score and VA in a cataract population. METHODS: Responses of 113 participants to the DVS were subjected to Guttman analysis. Standard criteria of scalability were evaluated that included the coefficient of reproducibility (CR), minimal marginal reproducibility (MMR), and coefficient of scalability (CS). The relationship between total item score and binocular visual acuity was determined. RESULTS: Five participants were excluded because of missing data. Regularity in the banding pattern of the scalogram of the 108 participants was suggestive of a deterministic Guttman scale. Analyses showed that DVS satisfies the criteria for classification as a valid unidimensional and cumulative scale, as CS (0.93), CR (0.99), and MMR (0.85) values fall within the desired range. The statistically significant correlation between the total item score and binocular VA was 0.24. CONCLUSIONS: The DVS fits the Guttman scale, supporting the deterministic model underlying the scale. It correlates poorly with VA, suggesting it taps aspects of visual performance and other issues beyond high-contrast VA. The DVS could be used as an outcome measure to evaluate change over time and could be used to set achievable treatment objectives because of its hierarchical properties.

The moderating role of employee positive well being on the relation between job satisfaction and job performance.

This research provides further clarification to the age-old quest to better understand the happy/productive worker thesis. Using data from 109 managers employed by a large (over 5000 employees) customer services organization on the West Coast of the United States, both job satisfaction (r=.36, p<.01, 95% CI=.18 to .52) and psychological well-being (PWB; r=.43, p<.01, 95% CI=.26 to .58) were associated with supervisory performance ratings. Using Fredrickson's (2001) broaden-and-build model as the theoretical base, the authors found that PWB moderates the relation between job satisfaction and job performance. Consistent with Fredrickson's model, performance was highest when employees reported high scores on both PWB and job satisfaction. This moderating effect of PWB may account for some of the inconsistent results of previous studies.