bluuebunny/crossref_metadata_2025_split huggingface dataset:
How large is the optic disc? Systematic errors in fundus cameras and topographers
Authors: Meyer Tina , Howland Howard C. 
Published: August 2002

Summary Purpose: To determine whether or not there are systematic differences in the areas of optic discs as measured by different machines using different measurement algorithms and whether racial or gender differences exist in optic disc area measurements. Methods: We examined the results of twenty‐three published studies on the size of normal optic discs of various patient populations. Studies differed in the type of instrument and method used to measure optic disc area, and the number, age, race and gender of subjects examined. Noticing that different machines exhibited statistically significant systematic differences in optic disc sizes of comparable populations, we computed a “normalization” factor for each machine based on these mean differences. Applying this normalization factor to the results, we then re‐examined the differences between racial and gender groups. Results:
By comparing the results of mean optic disc areas of different racial groups made with different machines, and normalizing results according to those of the Zeiss fundus camera, we found the normalization factors for the following machines to be, Zeiss fundus camera: 1 (by definition), Rodenstock Optic Disc Analyzer (RODA): 1.51, Topcon fundus camera: 1.04, Heidelberg Retina Tomograph (HRT): 1.15 and TopSS scanning laser ophthalmoscope: 1.29. That is, to bring the results of area measurements made with a RODA machine in line with those made with a Zeiss fundus camera, one should multiply the former by the factor 1.51. Using the normalized results, we confirmed the findings of previous authors that the optic disc areas of black subjects were statistically significantly larger than those of white subjects(
n
‐weighted mean effect=0.556±0.142 S.E.,
n
=5). Further, the meta‐analysis of various racial populations from five studies shows that males have significantly larger discs than females (
n
‐weighted mean effect=0.151±.055 S.E.,
n =9). Conclusion: Different machines and techniques give different results when populations of similar racial composition are measured. We recommend applying the above normalizing factors when comparing studies that employ different instruments.
Analysis of discrimination threshold on the tritan axis
Authors: García J. A. , Yebra A. , Hita E. , Romero J. 
Published: August 2002

SummaryDiscrimination thresholds on the tritan axis were obtained for an extensive group of 66 stimuli: in some of the stimuli,S‐cone trolands were held constant by keeping the product of theS‐cone excitation level and the luminance unchanged, while in others only the luminance was changed to establish variousS‐cone troland values. These thresholds depended clearly on theS‐cone value of the stimuli, while they remained almost constant against the retinal illumination. Thus, we noted that the excitation of theL−2M channel had practically no influence over the discrimination threshold on the tritan axis, although this independence of ΔS fromL−2M was not so obvious when theS value was high. With our data, we performed different fits, and found that the fit including the termsS,(L−2M) and(L+M) adapted better to our results.
Fatigue reduces tonic accommodation
Authors: Hasebe Satoshi , Graf Erich W. , Schor Clifton M. 
Published: August 2002

SummaryOcular accommodation adopts a mean baseline response level of approximately 1.0 D in the absence of blur feedback (open‐loop state). This baseline or tonic accommodation (TA) can be elevated following a sustained monocular accommodative response to a dioptric stimulus (lens adaptation) that exceeds the baseline open‐loop level of TA. The accommodative response to the lens persists in the open‐loop state (accommodative hysteresis), and eventually decays to a stable end‐point. Interestingly, if the baseline TA is high, the monocularly adapted accommodative state can decay to an end‐point that is below the initial pre‐adapted baseline level of the TA (counter‐adaptive response) (McBrien, N.A. and Millodot, M., (1988). Differences in adaptation of TA with refractive state. Invest. Ophthalmol. Vis. Sci., 29, 460–469).We have investigated the possible contribution of accommodation fatigue to the counter‐adaptive change in baseline TA following sustained accommodation. Two fatigue procedures were used while viewing a target at 66 or 33 cm. In a monocular condition, accommodation was stimulated for 3 min with lens values alternating from −1.5 to +1.5 D at a rate of 0.25 Hz. In the binocular condition, convergence was stimulated with alternating prism values from 9 prism diopters (PD) base‐out to 9 PD base‐in. Both monocular and binocular tasks resulted in a significant reduction of TA.These results suggest that previously reported reductions of baseline TA following sustained monocular accommodation or binocular convergence could have resulted from fatigue of the accommodative system. Accommodative fatigue could be responsible for the lower values of TA observed in counter‐adaptive responses to sustained accommodative or convergence effort.
Description of a method for neutralising the Stiles–Crawford effect
Authors: Scott Dion H. , Atchison David A. , Pejski Peter A. 
Published: August 2002

SummaryThe influence of the Stiles–Crawford effect on visual performance can be investigated by filters based on the apodisation model of the Stiles–Crawford effect. We describe the development of practical filters to achieve neutralisation. We present some results of the Stiles–Crawford function showing that the filters work well for expected errors in aligning filters in front of the eye.
Randomised controlled trial of an integrated versus an optometric low vision rehabilitation service for patients with age‐related macular degeneration: study design and methodology
Authors: Russell Wanda , Harper Robert , Reeves Barnaby , Waterman Heather , Henson David , McLeod David 
Published: August 2002

SummaryA number of studies have measured the outcomes of low vision care but these have usually been longitudinal case series, thus constituting very low quality of evidence for effectiveness. To date, there have been no randomised controlled trials (RCTs) which have evaluated the effectiveness and cost effectiveness of different models of care in low vision. The size of the low vision population and the paucity of systematic evaluation have created a pressing need for evidence about cost‐effectiveness in order to inform service developments for low vision rehabilitation. This paper describes the study design and methodology of a three‐arm RCT currently under way in Manchester. The baseline population recruited is also described. A traditional hospital‐based optometric service is being compared with an integrated service (comprising the addition of community‐based rehabilitation officer input) and with more generic community input (which is non‐integrated and is not vision specific). A wide range of outcome measures are being assessed at recruitment and 12 months post‐intervention, including low vision specific and generic quality of life measures, patterns of low vision aid use, and task performance. The rationale for the trial is discussed and the main study outcomes are described.
Clinical evaluation of the Shin‐Nippon SRW‐5000 autorefractor in children
Authors: Chat Sandy W. S. , Edwards Marion H. 
Published: August 2002

SummaryThe Canon Autoref R‐1 is an ‘open‐field’ autorefractor which has been widely used for research purposes for the past 20 years, but is no longer manufactured. A new autorefractor, the Shin‐Nippon SRW‐5000, is now available, and if measures using this instrument are shown to be equally accurate and reliable, is likely to replace the R‐1. Here we report on the accuracy and reliability (repeatability and reproducibility) of refraction measures in a paediatric population (from 4 to 8 years of age). Subject numbers were 44 for cycloplegic measures and 53 for non‐cycloplegic measures. As would be expected, agreement with cycloplegic refraction and reliability were better when SRW‐5000 measures were taken using cycloplegia. Repeatability results from the SRW‐5000 autorefractor, both with and without cycloplegia were similar to those reported for the Canon R‐1.
Clinical evaluation of the Shin‐Nippon SRW‐5000 autorefractor in adults
Authors: Mallen E. A. H. , Wolffsohn J. S. , Gilmartin B. , Tsujimura S. 
Published: August 2002

SummaryA clinical evaluation of the Shin‐Nippon SRW‐5000 (Japan), a newly released commercial autorefractor, was undertaken to assess its repeatability and validity compared to subjective refraction. Measurements of refractive error were performed on 200 eyes of 100 subjects (aged 24.4±8.0 years) subjectively (non‐cycloplegic) by one optometrist and objectively with the SRW‐5000 autorefractor by a second. Repeatability was assessed by examining the differences between the seven autorefractor readings taken from each eye and by re‐measuring the objective prescription of 50 eyes at a subsequent session. Although the SRW‐5000 read slightly more plus than subjective refraction (mean spherical equivalent +0.16±0.44 D), it was found to be highly valid (accurate) compared to subjective refraction and repeatable over the prescription range of +6.50 to −15.00 D examined. The Shin‐Nippon SRW‐5000 autorefractor is therefore a valuable complement to subjective refraction and as it offers the advantage of a binocular open field‐of‐view, has a great potential benefit for accommodation research studies.
Continuous recording of accommodation and pupil size using the Shin‐Nippon SRW‐5000 autorefractor
Authors: Wolffsohn J. S. , Gilmartin B. , Mallen E. A. H. , Tsujimura S. 
Published: August 2002

SummaryA newly released commercial autorefractor, the Shin‐Nippon SRW‐5000 (Japan), has been found to be valid compared to subjective refraction and repeatable over a wide prescription range. Its binocular open field‐of‐view allows the accommodative state to be monitored while a natural environment is viewed. In conventional static mode, the device can take up to 45 readings in 1 min using digital image analysis of the reflected retinal image of a measurement ring. Continuous on‐line analysis of the ring provides high (up to 60 Hz) temporal resolution of the refractive state to an accuracy of <0.001 D. Pupil size can also be analysed to a resolution of <0.001 mm. The measurement of accommodation and pupil size was relatively unaffected by eccentricity of viewing up to ±10° and instrument focusing inaccuracies of ±5 mm. The resolution properties of the analysis are shown to be ideal for measurement of dynamic accommodation and pupil responses.
Behavioral and Pharmacologic Treatment of Transformed Migraine With Analgesic Overuse: Outcome at 3 Years
Authors: Grazzi Licia , Andrasik Frank , D'Amico Domenico , Leone Massimo , Usai Susanna , Kass Steven J. , Bussone Gennaro 
Published: August 2002

Objective.—To determine whether combined treatment using medication and biofeedback would be more effective than drug treatment alone for treating transformed migraine complicated by analgesic overuse.Background.—Headaches that are chronic, daily, and aggravated by medication overuse are particularly difficult to treat.Methods.—Sixty‐one consecutive patients with transformed migraine and analgesic overuse were treated with inpatient pharmacologic therapy alone or with inpatient pharmacologic therapy combined with biofeedback‐assisted relaxation. All patients then were followed prospectively for 3 years.Results.—Both treatment groups exhibited similar levels of improvement immediately following treatment and for 1 year thereafter. At year 3, participants receiving combined treatment showed greater sustained improvement on two of three outcome measures assessed (ie, fewer days of headache and reduced consumption of analgesic medication). In addition, a greater number of patients assigned to pharmacologic treatment alone relapsed (ie, resumed overuse of analgesics) compared to patients receiving combined treatment.Conclusions.—These results suggest that a combination of pharmacologic and behavioral treatment is more effective than drug therapy alone in the long‐term management of transformed migraine with analgesic overuse. Confirmation of these findings, as well as extension to other forms of behavioral and cognitive‐behavioral treatment, is required.
Amitriptyline Versus Amitriptyline Combined With Fluoxetine in the Preventative Treatment of Transformed Migraine: A Double‐Blind Study
Authors: Krymchantowski Abouch Valenty , Silva Marcus Tulius , Barbosa Jackeline Soraya , Alves Luiz Anastácio 
Published: August 2002

Background and Objectives.—Antidepressants are often used to treat chronic daily headache disorders such as transformed migraine, in part because of the high prevalence of associated mood disorder. We conducted this study to evaluate the efficacy and tolerability of combined treatment with amitriptyline and fluoxetine compared with amitriptyline alone for chronic daily headache due to transformed migraine.Patients and Methods.—Thirty‐nine patients, 26 women and 13 men, aged 20 to 69 years (mean, 36.4; SD, 2.5) who fulfilled criteria for transformed migraine proposed by Silberstein et al were studied prospectively. Amitriptyline was dosed as follows: 8 mg/day for 6 days, 8 mg twice a day for 6 days, 20 mg/day for 6 days, and 20 mg twice a day for 45 days. In the group receiving combination therapy, fluoxetine was dosed and administered identically. The initial and end of the study (9 weeks) headache indices (frequency × intensity) were compared between groups.Results.—Twenty‐seven patients completed the study, 13 in the amitriptyline‐alone group (group 1) and 14 in the combination‐therapy group (group 2). The most frequent adverse event in both groups was dry mouth, and there was no significant difference in the occurrence of this or other adverse events between the two groups. Initial headache indices were similar for groups 1 and 2. The mean difference between the initial and final headache index for group 1 was 513.5 (P<.0005) and 893 (P<.0017) for group 2. The difference between the final headache index for the two groups was not significant (P>.207).Conclusions.—We were unable to demonstrate any significant benefit from amitriptyline plus fluoxetine over amitriptyline alone in the treatment of chronic daily headache/transformed migraine. Because of the small number of subjects involved and the short duration of our study, a type II error cannot be excluded.
Olanzapine in the Treatment of Refractory Migraine and Chronic Daily Headache
Authors: Silberstein Stephen D. , Peres Mario F.P. , Hopkins Mary M. , Shechter Aaron L. , Young William B. , Rozen Todd D. 
Published: August 2002

Background.—Olanzapine, a thienobenzodiazepine, is a new “atypical” antipsychotic drug. Olanzapine's pharmacologic properties suggest it would be effective for headaches, and its propensity for inducing acute extrapyramidal reactions or tardive dyskinesia is relatively low. We thus decided to assess the value of olanzapine in the treatment of chronic refractory headache.Methods.—We reviewed the records of 50 patients with refractory headache who were treated with olanzapine for at least 3 months. All previously had failed treatment with at least four preventative medications. The daily dose of olanzapine varied from 2.5 to 35 mg; most patients (n = 19) received 5 mg or 10 mg (n = 17) a day.Results.—Treatment resulted in a statistically significant decrease in headache days relative to baseline, from 27.5 ± 4.9 before treatment to 21.1±10.7 after treatment (P < .001, Studentttest). The difference in headache severity (0 to 10 scale) before treatment (8.7±1.6) and after treatment (2.2 ± 2.1) was also statistically significant (P < .001).Conclusion.—Olanzapine may be effective for patients with refractory headache, including those who have failed a number of other prophylactic agents. Olanzapine should receive particular consideration for patients with refractory headache who have mania, bipolar disorder, or psychotic depression or whose headaches previously responded to other neuroleptic medications.
Intravenous Valproate Sodium in the Treatment of Daily Headache
Authors: Schwartz Tamara H. , Karpitskiy Vladimir V. , Sohn Richard S. 
Published: August 2002

Background.—Treatment of chronic daily headache/transformed migraine is challenging, especially when it is complicated by overuse of analgesics, triptans, or both. One common approach involves the use of repetitive intravenous dihydroergotamine. We investigated the use of intravenous valproate sodium in the treatment of chronic daily headache/transformed migraine in patients who had contraindications to the use of or had failed treatment with dihydroergotamine.Methods.—We administered intravenous valproate sodium (Depacon) to patients with chronic daily headache/transformed migraine (loading dose 15 mg/kg, followed by 5 mg/kg every 8 hours). All analgesics and triptans were discontinued prior to treatment with divalproex sodium, and preventative medications for migraine were begun or continued. All patients received instruction in behavioral modification and the proper use of analgesics and triptans.Results.—Improvement in headache was reported by 80% of the patients treated, and valproate sodium was tolerated well by most.Conclusion.—Intravenous valproate sodium may be of assistance in the initial management of patients with chronic daily headache/transformed migraine and analgesic/triptan overuse, especially when dihydroergotamine is ineffective or contraindicated.
The Economic Impact of Migraine: An Analysis of Direct and Indirect Costs
Authors: Edmeads John , Mackell Joan A. 
Published: August 2002

Objective.—This study examined whether individuals with migraine incurred greater direct and indirect costs than a matched group free of migraines.Methods.—Using population‐based survey data, we matched individuals with migraine (n = 1087) and a migraine‐free control group one‐to‐one for age, sex, employment status, and number of comorbidities. We assessed the prior six months' direct medical care in terms of self‐reported hospital days and emergency department and physician visits. Costs were computed by multiplying utilization by unit costs and summing across categories. Indirect costs were calculated based on the number of days missed from employment or household activities.Results.—The sample was 80% female and had an average of 39 years and 0.4 comorbid conditions. Two‐thirds were employed. Migraineurs had higher direct medical costs over the prior six months ($522 versus $415, P = .039), primarily due to a greater frequency of physician and emergency department visits. The cost of lost productivity for the migraine group was also higher, by more than $200 (P = .014). The combined total for direct and indirect costs was $1,242 for migraineurs and $929 for the comparison group (P = .006). Additional analyses comparing those with moderate versus severe migraine demonstrated that more severe migraineurs had higher costs for lost productivity ($1,021 versus $251, P<.001) and higher costs when direct and indirect costs were combined ($1,656 versus $685, P<.001).Conclusion.—Migraine is an expensive illness and two‐thirds of the financial burden is linked to indirect costs. Consequently, individuals with migraine, employers, and insurance companies all have an economic stake in reducing the migraine burden.
Usefulness and Safety of Shortened Head‐Up Tilt Testing Potentiated with Sublingual Glyceryl Trinitrate in Older Patients with Recurrent Unexplained Syncope
Authors: Del Rosso Attilio , Ungar Andrea , Bartoli Paolo , Cellai Tommaso , Mussi Chiara , Marchionni Niccolò , Masotti Giulio , Di Studio della sincope dell'anziano The Gruppo Italiano 
Published: August 2002

OBJECTIVES: To evaluate the sensitivity and tolerability of shortened, glyceryl trinitrate (GTN)‐potentiated, head‐up tilt test (HUT) in patients older and younger than 65 with unexplained syncope and to compare the specificity of GTN‐potentiated HUT (GTN‐HUT) in older and younger controls.DESIGN: Methodological study.SETTING: Syncope units in secondary and tertiary hospitals.PARTICIPANTS: Three hundred twenty‐four consecutive patients with unexplained syncope (100 aged ≥65 (mean age ± standard deviation 73 ± 6; 35 men) and 224 aged <65 (41 ± 15; 111 men)) and 64 controls (29 aged ≥65 (73 ± 6; 13 men) and 35 aged <65 (42 ± 13; 16 men)).INTERVENTION: Patients and controls were tilted upright to 60° for 20 minutes. If syncope did not occur, sublingual GTN (400 μg) was administered and 60° HUT was continued for 15 minutes. Responses were classified as positive, negative, or exaggerated (slow decrease in blood pressure with a slight decrease in heart rate after GTN).MEASUREMENTS: Electrocardiogram and arterial pressure were monitored continuously.RESULTS: GTN‐HUT was positive in 60% and 66% (NS), negative in 29% and 33% (NS), and exaggerated in 11% and 1% (P < .001) of older and younger patients, respectively. In older and younger controls, the GTN‐HUT was negative in 70% and 86% and exaggerated in 28% and 9% of cases, respectively, (P < .05). The overall specificity (considering as negative also the exaggerated responses) was 97% in older and 94% in younger subjects. No patient or control experienced serious side effects.CONCLUSION: The shortened GTN‐HUT provides satisfactory positivity rate and specificity in older patients. This test may be considered as a diagnostic tool in assessing recurrent unexplained syncope in older patients.
Falls and Fear of Falling: Which Comes First? A Longitudinal Prediction Model Suggests Strategies for Primary and Secondary Prevention
Authors: Friedman Susan M. , Munoz Beatriz , West Sheila K. , Rubin Gary S. , Fried Linda P. 
Published: August 2002

OBJECTIVES: Previous cross‐sectional studies have shown a correlation between falls and fear of falling, but it is unclear which comes first. Our objectives were to determine the temporal relationship between falls and fear of falling, and to see whether these two outcomes share predictors.DESIGN: A 20‐month, population‐based, prospective, observational study.SETTING: Salisbury, Maryland. Each evaluation consisted of a home‐administered questionnaire, followed by a 4‐ to 5‐hour clinic evaluation.PARTICIPANTS: The 2,212 participants in the Salisbury Eye Evaluation project who had baseline and 20‐month follow‐up clinic evaluations. At baseline, subjects were aged 65 to 84 and community dwelling and had a Mini‐Mental State Examination score of 18 or higher.MEASUREMENTS: Demographics, visual function, comorbidities, neuropsychiatric status, medication use, and physical performance–based measures were assessed. Stepwise logistic regression analyses were performed to evaluate independent predictors of falls and fear of falling at the follow‐up evaluation, first predicting incident outcomes and then predicting fall or fear‐of‐falling status at 20 months with baseline falling and fear of falling as predictors.RESULTS: Falls at baseline were an independent predictor of developing fear of falling 20 months later (odds ratio (OR) = 1.75; P < .0005), and fear of falling at baseline was a predictor of falling at 20 months (OR = 1.79; P < .0005). Women with a history of stroke were at risk of falls and fear of falling at follow‐up. In addition, Parkinson's disease, comorbidity, and white race predicted falls, whereas General Health Questionnaire score, age, and taking four or more medications predicted fear of falling.CONCLUSION: Individuals who develop one of these outcomes are at risk for developing the other, with a resulting spiraling risk of falls, fear of falling, and functional decline. Because falls and fear of falling share predictors, individuals who are at a high risk of developing these endpoints can be identified.