The charge exchange recombination spectroscopy diagnostic on the upgraded Lithium Tokamak eXperiment (LTX-ß).

The Lithium Tokamak eXperiment has undergone an upgrade to LTX-ß, a major part of which is the addition of neutral beam injection (NBI). NBI has allowed for a new charge exchange recombination spectroscopy (CHERS) system to be installed in order to measure impurity concentrations, ion temperature, and toroidal velocity. Previously on LTX measuring these parameters relied on passive spectroscopy and inversion techniques and had large uncertainty. The CHERS system has 52 total views, split into four groups of 13, half facing toward the beam and half symmetrically facing away from the beam, so the background non-beam related emission can be simultaneously subtracted. Both sets of views sample a major radius of 27-59 cm, with resolution through the beam of 1.5-2.5 cm. LTX-ß is expected to have its magnetic axis near 35 cm, with minor radii of 18-23 cm. Three separate spectrometers will be used for the diagnostic, giving the system great flexibility to simultaneously measure emission from multiple impurity lines. The viewing optics are f/1.8, allowing all of the spectrometers to be fully illuminated. Design and calibration of the system as well as the advantages of various configurations of the spectrometers will be highlighted.

The usefulness of Vistech and FACT contrast sensitivity charts for cataract and refractive surgery outcomes research.

AIM: To investigate the repeatability and sensitivity of two commonly used sine wave patch charts for contrast sensitivity (CS) measurement in cataract and refractive surgery outcomes. METHODS: The Vistech CS chart and its descendant, the Functional Acuity Contrast Test (FACT), were administered in three experiments: (1) Post-LASIK and age matched normal subjects; (2) Preoperative cataract surgery and age matched normal subjects; (3) Test-retest repeatability data in normal subjects. RESULTS: Contrast sensitivity was similar between post-LASIK and control groups and between the Vistech and FACT charts. The percentage of subjects one month post-LASIK achieving the maximum score across spatial frequencies (1.5, 3, 6, 12, 18 cycles per degree) were (50, 33, 13, 13, 0 respectively) for FACT, but only (0, 0, 13, 4, 0 respectively) for Vistech. A small number of cataract patients also registered the maximum score on the FACT, but up to 60% did not achieve the minimum score. Test-retest intraclass correlation coefficients varied from 0.28 to 0.64 for Vistech and 0.18 to 0.45 for FACT. Bland-Altman limits of agreement across spatial frequencies were between +/-0.30 and +/-0.85 logCS for Vistech, and +/-0.30 to +/-0.75 logCS for FACT. DISCUSSION: The Vistech was confirmed as providing poorly repeatable data. The FACT chart, likely because of a smaller step size, showed slightly better retest agreement. However, the reduced range of scores on the chart due to the smaller step size led to ceiling (post-LASIK) and floor (cataract) effects. These problems could mask subtle differences between groups of patients with near normal visual function as found post-refractive or cataract surgery. The Vistech and FACT CS charts are ill suited for refractive or cataract surgery outcomes research.

Refractive error changes in cortical, nuclear, and posterior subcapsular cataracts.

AIMS: To determine the effect of the three main morphological types of cataract on refractive error. METHODS: Data were prospectively collected from 77 subjects (age 67 (SD 8) years) with one morphological type of cataract. 34 had cortical, 21 had nuclear, and 21 had posterior subcapsular cataract. 22 subjects with clear lenses (60 (7) years) were recruited as controls. The spherical equivalent and astigmatic vector change between spectacle correction and optimal refraction were calculated. RESULTS: The cortical cataract group showed a significant astigmatic change of 0.71 (0.67) D (mean (1 SD)) compared to the control group (0.24 (0.20) D), with 24% outside the 95% confidence limit (0.63 D). The nuclear cataract group showed a significant myopic shift of -0.38 (0.60) D compared to the control group (+0.02 (0.21) D), with 52% beyond the minus 95% confidence limit (-0.39 D). CONCLUSION: A quarter of subjects with cortical cataract showed larger changes in astigmatism than subjects with clear lenses. This is probably because of the localised refractive index changes along cortical spoke opacities within the pupillary area. The well known myopic shift of nuclear cataract was also demonstrated.

Loss of visual acuity is the main reason why reading addition increases after the age of sixty.

PURPOSE: To determine why the reading addition increases after the age of 55 to 60 years when accommodation is zero. METHODS: Distance and near visual acuities, arm length, habitual near working distance, reading addition, and pupil diameter were measured in 44 subjects aged >60 years (mean, 72.9 +/- 5.7). Reading addition values were attained using three techniques: least-plus addition using both N-notation text and MN-READ text and the cross-cylinder technique. RESULTS: The mean dioptric working distance was 2.75 +/- 0.40 D. The reading addition found using N-notation text (+2.21 +/- 0.38 D) was significantly lower than that measured using MN-READ text (+2.48 +/- 0.49 D) or the cross-cylinder method (+2.53 +/- 0.44 D). The reading addition was positively correlated with the dioptric working distance (r = 0.47, p < 0.01), and decreasing habitual working distance was associated with poorer visual acuity (r = -0.42, p < 0.01). CONCLUSIONS: Our results suggest that decreases in near visual acuity after 60 years of age lead to a reduction in habitual working distance, which increases text angular subtense. In turn, the reduced working distance requires a greater reading addition. Increases in depth of field associated with both suprathreshold text (N-notation) and lower visual acuity lead to reading additions being less than the dioptric working distance.

Development of a reading speed test for potential-vision measurements.

PURPOSE: Previous studies suggest that optimal reading speed is unaffected by cataract, yet is significantly reduced in age-related macular degeneration (ARMD ). This raises the question of whether a reading speed test could be developed to assess potential vision after cataract surgery. METHODS: Nineteen subjects with cataract, 15 with ARMD, and 13 control subjects with normal, healthy eyes read Bailey-Lovie word charts aloud, and subsequently, critical print size and optimal reading speed were calculated. Measurements were also taken with the charts in reversed-contrast polarity and after pupillary dilation. RESULTS: Although the subjects with cataract had reduced word acuity and increased critical print size, optimal reading speed was similar to that of the control group at a mean of approximately 100 wpm. Optimal reading speed in the subjects with ARMD was substantially worse (mean of 39 wpm). Reversing the contrast polarity of the charts slightly increased the word acuity and optimal reading speed of the subjects with cataract. CONCLUSIONS: The results suggest that optimal reading speed would be useful as a potential-vision test. The proposed test would use text size of at least 1.32 degrees (1.2 log minimum angle of resolution [logMAR]), and pupil dilation would be unnecessary. A reading test with black letters on a white background would be adequate, because charts with reversed-contrast polarity made minimal difference in reading speed.

Optimal reading speed in simulated cataract: development of a potential vision test.

Previous studies suggest that optimal reading speed is unaffected by cataract, yet is significantly reduced in age-related macular disease. This raises the question of whether a reading speed test could be developed to assess potential vision after cataract surgery. In this study, 20 young subjects, with and without a simulation of dense cataract, read aloud Bailey-Lovie word charts. From the results, critical print size, optimal reading speed and word acuity were calculated. The simulated cataract reduced word acuity and increased the critical print size, yet optimal reading speed remained unchanged. Measurements were also taken with the charts in reversed contrast polarity. Reversing the contrast polarity of the charts improved the word acuity and optimal reading speed with the cataract simulation. The results suggest that optimal reading speed could be used as a potential vision test. Further investigations using patients with cataract and ARMD are required.

N100 evoked potential latency variation and startle in schizophrenia.

The contribution of evoked potential (EP) latency jitter, a measure of CNS temporal variability, on startle and EP gating defects in schizophrenic subjects has not been characterized. The amplitude of the N100/P200 EP complex (peak to trough) derived using a time-locked averaging procedure, N100 EP latency jitter derived from single trial analysis, acoustic startle response and clinical symptoms were measured in 51 schizophrenic subjects. N100 latency jitter was inversely correlated with N100/P200 EP amplitude in both cross-sectional and longitudinal analysis. Subjects with elevated EP gating ratios (>0.5) had similar latency jitter values for initial (S1) and test (S2) stimuli, while subjects with a low gating ratio (0-0.5) had a lower level of S1 latency jitter. Temporal variability thus plays a significant and complex role in previously reported sensory gating deficits in schizophrenic subjects.

Improving the reliability of visual acuity measures in young children.

Whilst the methodology of adult letter acuity measurement has been substantially refined over the last two decades, relatively little development has occurred in methods for quantifying letter acuity in young children. This study compares a recently developed visual acuity test (Glasgow Acuity Cards), which incorporates several key design features used in adult test charts to improve the sensitivity and reliability of visual acuity measurements. The equivalence of acuity measurements made with Glasgow Acuity Cards were compared with the Bailey-Lovie logMAR chart and Snellen chart in adults, and with traditional Single Letter Acuity and a modified Single Letter Acuity test in children. The test-retest reliability of acuity measurements made with Glasgow Acuity Cards and the Single Letter Acuity tests were also assessed in a large group of visually normal children. In addition, the ability of the pre-school letter acuity tests to detect differences in acuity between the two eyes, and to detect amblyopia were examined. Ninety-five percent of vision measurements made with the Bailey-Lovie chart and Glasgow Acuity Cards differ by less than 0.07 log unit. Furthermore, the sensitivity of Glasgow Acuity Cards to detecting changes in acuity longitudinally and inter-ocular differences in acuity is considerably greater as compared with traditional Single Letter Acuity tests. Improvements in paediatric acuity chart design are important for the effective detection and management of children with amblyopia.

Comparison of recommendations by urologists and radiation oncologists for treatment of clinically localized prostate cancer.

CONTEXT: Multiple treatment options are available for men with prostate cancer, but therapeutic recommendations may differ depending on the type of specialist they consult. OBJECTIVE: To define and contrast the distribution of management recommendations by urologists and radiation oncologists for a spectrum of men with prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: Mail survey sent in 1998 to a random sample of physicians in the United States, who were listed as urologists (response rate 64%, n=504) and radiation oncologists (response rate 76%, n=559) in the American Medical Association Registry of Physicians and practicing at least 20 hours per week. MAIN OUTCOME MEASURE: Questionnaire addressing beliefs and practices regarding prostate cancer management. RESULTS: Forty-three percent of radiation oncologists vs 16% of urologists would recommend routine prostate-specific antigen testing for men aged 80 years and older. For men with moderately differentiated, clinically localized cancers, and a more than 10-year life expectancy, 93% of urologists chose radical prostatectomy as the preferred treatment option, while 72% of radiation oncologists believed surgery and external beam radiotherapy were equivalent treatments. For most tumor grades and prostate-specific antigen levels, both specialty groups were significantly more likely to recommend the treatment in their specialty than the other treatment. Both groups reported giving patients similar estimates of the risks of complications due to surgery and radiation. Neither group favored watchful waiting in their treatment management except for a subset of men with life expectancies of less than 10 years and cancers with very favorable prognoses (Gleason score of 3 or 4 and prostate-specific antigen level

Diagnosing and treating chronic prostatitis: do urologists use the four-glass test?

OBJECTIVES: To examine the diagnosis and treatment of chronic prostatitis, we conducted a national mail survey of practicing urologists in 1998. METHODS: Probability samples were drawn from the American Medical Association Registry of Physicians. RESULTS: Five hundred four urologists responded (response rate 64%). Urologists reported seeing a median of 30 patients (interquartile range 11 to 60) newly diagnosed with chronic prostatitis in the previous 12 months. Eighty percent of urologists responded that they "rarely" (47%) or "never" (33%) performed the Meares-Stamey four-glass diagnostic test. Only 4% answered "almost always." Forty percent of urologists responded that they treat "all" their patients with antibiotics and 42% more responded that they treat "more than half" with antibiotics. Physicians who routinely performed the four-glass test did not differ in antibiotic use from those who used the test less often; however, they were more likely to use treatment other than antibiotics. For example, alpha-blockers were used in one half or more of the patients by only 35% of physicians who never do the four-glass test compared with 42% who rarely do the test and 57% who do the test more often (P = 0.002). Results were similar for treatment with natural remedies. CONCLUSIONS: Urologists frequently diagnose chronic prostatitis but rarely perform the four-glass diagnostic test. Use of the four-glass test does not appear to affect urologists' antibiotic treatment patterns. Although bacterial prostatitis is thought to be rare, antibiotic use in the population of men with prostatitis is not. The four-glass test and empiric antibiotics are practices in the diagnosis and treatment of prostatitis that deserve scrutiny.

Improvements in clinical and functional vision and quality of life after second eye cataract surgery.

PURPOSE: To determine whether there is a need for second eye cataract surgery or whether cataract surgery in one eye provides sufficiently adequate vision. METHODS: The vision of 43 patients was assessed using a battery of clinical vision tests, performance-based functional vision tests, and quality of life questionnaires, both before and a few months after cataract surgery. Twenty-five patients underwent second eye surgery and 18 patients underwent first-eye surgery. To determine whether cataract surgery returned vision to normal levels, a control group of 25 subjects of a similar age with normal, healthy eyes was also assessed. RESULTS: Overall, greater improvements occurred in most aspects of vision after first eye surgery than after second eye surgery. However, second eye surgery provided similar improvements in mobility orientation and self-reported night driving to those after first eye surgery, and substantially greater improvements in stereoacuity and reductions in anisometropia. CONCLUSIONS: The study provides additional evidence to support the need for second eye cataract surgery. Second eye surgery may be particularly important to improve mobility orientation and the avoidance of falls.

Effect of aging on the monochromatic aberrations of the human eye.

We measured the contrast sensitivity (CS) of a group of older subjects through natural pupils and compared the results with those from a group of younger subjects. We also measured each subject's monochromatic ocular wave-front aberrations using a crossed-cylinder aberroscope and calculated their modulation transfer functions (MTF's) and root-mean-squared (RMS) wave-front aberrations for fixed pupil diameters of 4 mm and 6 mm and for a natural pupil diameter. The CS at a natural pupil diameter and the MTF computed for a fixed pupil diameter were found to be significantly poorer for the older group than for the younger group. However, the older group showed very similar MTF's and significantly smaller RMS wave-front aberrations compared with the younger group at their natural pupil diameters, owing to the effects of age-related miosis. These results suggest that although monochromatic ocular wave-front aberrations for a given pupil size increase with age, the reduction in CS with age is not due to this increase.

Epilogue: Early lessons from CAHPS Demonstrations and Evaluations. Consumer Assessment of Health Plans Study.

OBJECTIVES: The Consumer Assessment of Health Plans Study (CAHPS) was developed to provide an integrated set of tested, standardized surveys to obtain meaningful information from health plan enrollees and their experiences. Many organizations began to implement CAHPS in 1997. Formal evaluations of the experiences of three demonstration sites with implementing CAHPS (ie, process evaluations) and the impact of CAHPS on consumer's choices (ie, outcome evaluations) were conducted. This article reports on the early findings and feedback from our process evaluations about the sites' experiences with using CAHPS. Results are presented from the first round demonstration sites, including the lessons learned during the demonstrations. Our plans for future demonstrations and evaluations are included. METHODS: A similar evaluation design and instruments were used across demonstration sites. The process evaluation to monitor program intervention included on-site interviews, off-site review of documents, and focus groups with consumers. RESULTS: There are 4 early results from the CAHPS demonstrations: (1) the CAHPS survey covers topics of importance to sponsors, is of reasonable length, and can be administered quickly; (2) the report templates are being used effectively, but sponsors vary widely in their preferences for summarizing and presenting CAHPS ratings; (3) standardized or off-the-shelf products are aspects of CAHPS that sponsors value highly, while emphasizing need for further development; and (4) because surveys like CAHPS require multiple within-plan samples to make plan comparisons, they require a substantial investment and may be affordable only for large sponsors. CONCLUSION: The first round CAHPS demonstrations highlighted the strengths of the integrated surveys and the areas for improving the products and the implementation process.

Management of patients with age-related cataract.

The majority of patients referred because of age-related cataract should be referred when their ability to function in their desired lifestyle is reduced due to poor vision. Generally the decision to refer should not be based on visual acuity, and the referral letter should reflect this. Patients who are not referred should not just be monitored until referral. There are several simple strategies for improving their vision which should be discussed with the patient, such as broad-brimmed hats or caps, typoscopes, anti-reflection coats and UV-blocking tints. There are also several strategies which may delay the progress of their cataract, which include reducing UV exposure and cigarette smoking and taking anti-oxidant vitamin supplements. These could also be discussed with the patient.

Visual acuity versus letter contrast sensitivity in early cataract.

Large and small letter contrast sensitivity and visual acuity were assessed in 37 elderly eyes (mean VA -0.01 logMAR, Snellen 6/6) and their lens opacities were categorised and graded using the LOCS III system. Large letter contrast sensitivity was often not reduced in cataract from age-matched normal values and provided limited information. Small letter contrast sensitivity was shown to be a more sensitive measure of early cataract than visual acuity and large letter contrast sensitivity. Its usefulness may be limited by its strong correlation with visual acuity (r2 = 0.70), which is the standard and traditional measure of vision in cataract.

A comparison of low vision clinic data with low vision survey and blindness registration information.

PURPOSE: To determine whether low vision demographic data provided by low vision clinic data are comparable to that provided by blindness registration and disability questionnaire information. METHODS: Low vision demographic data for Canada and Ontario within the postcensus Health and Activity Limitation Survey (HALS 1991) were obtained from Statistics Canada. These data were compared with 4744 reports of low vision examinations obtained in a multi-center low vision clinic study in Ontario, Canada (1991-1994) and appropriate annual figures from the Canadian National Institute for the Blind (CNIB). RESULTS: Data from the low vision clinic study and the CNIB were similar. The low vision clinic study (and CNIB) reported far fewer adults (15 to 64 years) and far more seniors (65+ years) obtaining low vision examinations than suggested by HALS. CONCLUSIONS: HALS does not report on patients with low vision, as defined in low vision clinics. The differences between survey, low vision clinic, and blindness registration data are presented.

Demographic characteristics of the vision-disabled elderly.

PURPOSE: To profile certain demographic features of the low-vision population in Ontario, Canada. METHODS: Sixty-six optometrists or optometry centers, 8 ophthalmologists, and 23 Canadian National Institute for the Blind rehabilitation worker teams were recruited to the study. They were required to report on their low-vision examinations during a 3-year period. RESULTS: Reports from 4744 low-vision examinations were received. Of the patients examined, 71% were over age 65 (subsequently called seniors or elderly), and 55% were over age 75. Ninety percent of all the patients lived in households and 10% lived in institutions. Seniors made up 71% of the patients living in households and 88% of the patients living in institutions. Most of the seniors were women (65%), and 57% had functional limitations in addition to low vision, most commonly limitations in mobility, hearing, or agility. Age-related maculopathy was the primary diagnosis in 75% of seniors, and the most common secondary diagnosis was cataract (46%). The main objective for most elderly low-vision patients was to gain improvement in personal reading (75%). CONCLUSIONS: The vast majority of low-vision patients were elderly, the largest number being 75 to 84 years old. When older senior low-vision patients (> or = 85 years) were compared with younger seniors (65 to 74 years), the older seniors were more likely to be women, more likely to have additional functional limitations, more likely to live in an institution, and more likely to have age-related maculopathy and cataract. Whether some elderly low-vision patients may be helped by cataract surgery needs to be determined.