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Biomedical subjects

D S Friedman

Publications and source records attributed to D S Friedman.

At least 19 recordsLinked to original sources
PubMed2002

VF-14 item specific responses in patients undergoing first eye cataract surgery: can the length of the VF-14 be reduced?

AIMS: To report the item specific responses of the VF-14 in a population of patients undergoing cataract surgery in their first eye and to determine whether or not the VF-14 can be reduced without compromising its performance as an index of cataract related visual impairment. METHODS: The item specific responses to the VF-14 were analysed before (771 patients) and 4 months after (552 patients) cataract surgery in one eye to determine if the VF-14 index can be reduced without compromising its performance. Patients studied were selected from a cross sectional longitudinal study of patients undergoing cataract surgery in 72 ophthalmologist's offices located in three metropolitan regions of the United States. RESULTS: Pairwise correlations between items in the VF-14 were all less than 0.6, indicating that no items could be removed solely on the basis of redundancy. 10 items correlated moderately with change in trouble, and 11 correlated moderately with change in satisfaction (r >0.15) at 4 months after cataract extraction. Eleven items demonstrated an effect size >0.4 at 4 months. These 11 items were either important for detecting cataract related functional disability or for quantifying the extent to which cataract impaired function. Additionally, 11 items were needed to detect adequately individuals with functional impairment. Three items (recognising people, cooking, and reading large print) were less responsive to cataract extraction and were more strongly associated with ocular comorbidities. CONCLUSIONS: While previous reports indicate that the VF-14 can be significantly shortened, our analysis only justifies removing three items. While the resulting VF-11 has properties similar to the VF-14, the limited time savings do not justify altering this already validated instrument.

Aged↗
PubMed2001

Diagnostic capabilities of frequency-doubling technology, scanning laser polarimetry, and nerve fiber layer photographs to distinguish glaucomatous damage.

PURPOSE: To investigate the ability of three diagnostic tests: frequency-doubling technology (FDT), scanning laser polarimetry (GDx), and nerve fiber layer (NFL) photographs to distinguish normal from glaucomatous eyes. METHODS: Data were obtained in a cross-sectional, hospital clinic-based study, including one eye from each of 253 persons older than 40 years (68 normal, 94 glaucoma suspects and 91 glaucoma patients). We performed a comprehensive ocular examination, as well as static automated perimetry (Humphrey 24-2), screening FDT, GDx, optic nerve stereoscopic photographs and high-contrast NFL photographs. RESULTS: The following were significantly different for glaucomatous patients compared with suspects and normals: mean values of mean deviation (MD, Humphrey 24-2) and corrected pattern standard deviation (CPSD), 11 GDx indices, mean FDT testing time and missed points, and NFL graded defects (ANOVA, Mantel-Haenszel test; p = 0.0001). Using Humphrey 24-2 test results and clinical assessment as the defining features of glaucoma, we found that the optimal mix of sensitivity and specificity values were 84% and 100% for FDT (presence of any defect); 62% and 96% for GDx (The Number, cut-off value of 27); and, 95% and 82% for NFL photographs (presence of any abnormality). FDT testing took the least time to be administered. CONCLUSIONS: The FDT had the best diagnostic performance. Neural network analysis of GDx data outperformed other elements of its software.

Cross-Sectional Studies↗
PubMed2001

A decision analysis of anesthesia management for cataract surgery.

PURPOSE: To compare the trade-offs in cost and preference of various anesthesia management strategies for cataract surgery. METHODS: Six strategies, differing in sedation, local anesthetic, and monitoring approach, were chosen for comparison. For each strategy, potential complications, and conversions to different anesthesia approaches were modeled. A panel of physicians and anesthetists, well versed in the literature and practice of the anesthesia management of cataract surgery, assigned preference values to the strategies and potential outcomes (0 to 1 scale). Probability estimates were obtained from a study of 19,557 cataract surgeries and from the panel. Cost estimates were derived from several sources. The model was analyzed to determine the strategies associated with the highest expected preference and lowest expected cost. RESULTS: The strategy associated with the highest net preference was intravenous sedation with block anesthesia and an anesthesiologist present throughout the case. The expected net preference for this strategy was 19% greater than the net preference for the next most preferred strategy, oral sedation with block anesthesia and an anesthesiologist on call (0.88 versus 0.74), but the expected anesthesia costs per case were much greater ($324 versus $42). Results were sensitive to plausible variation in the preference values assigned to the six initial management strategies and to the cost of topical versus block anesthesia. CONCLUSION: This analysis emphasizes that cost and preference are important considerations when choosing an anesthesia management strategy for cataract surgery. For some surgeries, substantial cost savings may be available for a small change in preference.

Anesthesia, Local↗
PubMed2001

The methodologic quality of clinical trials on regional anesthesia for cataract surgery.

OBJECTIVE: To assess the methodologic quality of published randomized trials of regional anesthesia management strategies for cataract surgery. DESIGN: Literature review and analysis. METHOD: We performed a systematic search of the literature to identify all articles pertaining to regional anesthesia for cataract surgery on adults. Overall quality scores and scores for individual methodologic domains were based on the evaluations of two investigators experienced in methodologic research who independently reviewed all relevant articles using a quality abstraction form. MAIN OUTCOME MEASURES: Study quality in each of five domains: representativeness, bias and confounding, intervention description, outcomes and follow-up, and statistical quality and interpretation. RESULTS: Eighty-two randomized clinical trials were identified with a mean overall quality score of 44%. The mean domain scores ranged from 37% for representativeness to 58% for outcomes and follow-up. Forty percent or fewer studies received the maximum score for reporting the setting, the population, and the start and end dates; describing the inclusion and exclusion criteria; adequately randomizing subjects; and adequately masking individuals participating in the study. Key outcomes were often inadequately reported, including the distribution of patient-reported pain scores and the mean surgical time. CONCLUSIONS: Greater attention to methodologic quality and detailed reporting of study results will improve the ability of readers to interpret the results of clinical trials assessing regional anesthesia for cataract surgery.

Adult↗
PubMed2001

Synthesis of the literature on the effectiveness of regional anesthesia for cataract surgery.

OBJECTIVE: To synthesize the findings of the randomized trials of regional anesthesia management strategies for cataract surgery. DESIGN: Literature review and analysis. METHOD: The authors performed a systematic search of the literature to identify all articles pertaining to regional anesthesia during cataract surgery on adults. One investigator abstracted the content of each article onto a custom-designed form. A second investigator corroborated the findings. The evidence supporting the anesthesia approaches was graded by consensus as good, fair, poor, or insufficient. MAIN OUTCOME MEASURES: Evidence supporting the effectiveness of different forms of regional anesthesia. RESULTS: There was good evidence that retrobulbar and peribulbar blocks provide equivalent akinesia and pain control during cataract surgery. Additionally, sub-Tenon's blocks were at least as effective as retrobulbar and peribulbar blocks. There was good evidence that retrobulbar block provides better pain control during surgery than topical anesthesia, and there was fair evidence that peribulbar block provides better pain control than topical anesthesia. CONCLUSIONS: This synthesis of the literature demonstrates that currently used approaches to anesthesia management provide adequate pain control for successful cataract surgery, but there is some variation in the effectiveness of the most commonly used techniques. Data are needed on patient preferences to determine the optimal strategies for anesthesia management during cataract surgery.

Anesthesia, Local↗
PubMed2001

Activity restrictions as part of the discharge management for children with a traumatic head injury.

This article describes a proactive management strategy that is currently part of the discharge protocol for children seeking care for a head injury (HI) at a pediatric and adolescent trauma center. The strategy consists of setting activity restrictions for children hospitalized and those seen in the emergency department after a HI that may or not have been sports related. It was developed based on extensive clinical experience with families of children with a HI and existing guidelines for returning athletes to sports. Possible merits and pitfalls of the strategy are discussed.

Activities of Daily Living↗
PubMed2000

Algorithm for interpreting the results of frequency doubling perimetry.

PURPOSE: To evaluate an algorithm for the identification of glaucomatous visual field defects with the screening mode of frequency doubling technology. METHODS: Screening-mode frequency doubling technology and Swedish interactive threshold algorithm perimetry were performed on 137 of 150 consecutive patients referred to a glaucoma specialist. We created an algorithm for the frequency doubling technology that gave increased importance to both more severe defects and defects closer to fixation. These values were then compared with the results of the Swedish interactive threshold algorithm visual fields evaluated by the glaucoma hemifield test, two masked glaucoma specialists, and a published definition of glaucomatous damage to determine sensitivity and specificity of the frequency doubling technology screening mode for detecting glaucoma.

Adult↗
PubMed1999

Methodological variations in estimating apparent progressive visual field loss in clinical trials of glaucoma treatment.

OBJECTIVES: To compare methods to estimate the incidence of visual field progression used by 3 large randomized trials of glaucoma treatment by applying these methods to a common data set of annually obtained visual field measurements of patients with glaucoma followed up for an average of 6 years. METHODS: The methods used by the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Initial Glaucoma Treatment Study (CIGTS), and the Early Manifest Glaucoma Treatment study (EMGT) were applied to 67 eyes of 56 patients with glaucoma enrolled in a 10-year natural history study of glaucoma using Program 30-2 of the Humphrey Field Analyzer (Humphrey Instruments, San Leandro, Calif). The incidence of apparent visual field progression was estimated for each method. Extent of agreement between the methods was calculated, and time to apparent progression was compared. RESULTS: The proportion of patients progressing was 11%, 22%, and 23% with AGIS, CIGTS, and EMGT methods, respectively. Clinical assessment identified 23% of patients who progressed, but only half of these were also identified by CIGTS or EMGT methods. The CIGTS and the EMGT had comparable incidence rates, but only half of those identified by 1 method were also identified by the other. CONCLUSIONS: The EMGT and CIGTS methods produced rates of apparent progression that were twice those of the AGIS method. Although EMGT, CIGTS, and clinical assessment rates were comparable, they did not identify the same patients as having had field progression.

Disease Progression↗
PubMed1999

Racial differences in the prevalence of age-related macular degeneration: the Baltimore Eye Survey.

OBJECTIVE: To determine the prevalence of age-related macular degeneration (AMD) and signs of age-related maculopathy in a population-based sample of blacks and whites 40 years of age or older from East Baltimore. DESIGN: Cross-sectional population-based study. PARTICIPANTS: A total of 5308 black and white subjects received a screening eye examination that included fundus photography. MAIN OUTCOME MEASURES: Stereoscopic color fundus photographs were graded for the presence and severity of drusen, pigmentary abnormalities, geographic atrophy, and choroidal neovascularization in the macula. RESULTS: Drusen > or = 64 microm were identified in about 20% of individuals in both groups, but large drusen (>125 microm) were more common among older whites (15% for whites versus 9% for blacks over 70). Pigmentary abnormalities were also more common among older whites (7.9% for whites versus 0.4% for blacks over 70). Age-related macular degeneration was more prevalent among whites than blacks. The prevalence of AMD was 2.1 % among whites over 70 years of age. No cases of AMD were detected among 243 black subjects in this age group. Logistic regression adjusting for age, sex and smoking (current, former, or never) detected an odds ratio of 4.4 (95% confidence interval: 1.5-12.4) for whites with AMD compared with blacks. CONCLUSION: Although drusen are common in both blacks and whites over the age of 40, more severe forms of age-related maculopathy and late AMD are more prevalent in older whites.

Adult↗
PubMed1999

Single-molecule analysis of kinesin motility reveals regulation by the cargo-binding tail domain.

Conventional kinesin transports membranes along microtubules in vivo, but the majority of cellular kinesin is unattached to cargo. The motility of non-cargo-bound, soluble kinesin may be repressed by an interaction between the amino-terminal motor and carboxy-terminal cargo-binding tail domains, but neither bead nor microtubule-gliding assays have shown such inhibition. Here we use a single-molecule assay that measures the motility of kinesin unattached to a surface. We show that full-length kinesin binds microtubules and moves about ten times less frequently and exhibits discontinuous motion compared with a truncated kinesin lacking a tail. Mutation of either the stalk hinge or neck coiled-coil domain activates motility of full-length kinesin, indicating that these regions are important for tail-mediated repression. Our results suggest that the motility of soluble kinesin in the cell is inhibited and that the motor becomes activated by cargo binding.

Amino Acid Sequence↗
PubMed1999

Digital image capture and automated analysis of posterior capsular opacification.

PURPOSE: To develop and validate a digital imaging and analysis technique for assessing the extent of posterior capsular opacification after cataract surgery. METHODS: Retroillumination images of the posterior capsule were obtained by using a digital camera mounted on a slit lamp. The images were analyzed using an available image analysis software program. The image acquisition and analysis techniques were tested for face validity, reproducibility, and the ability to detect progression of capsular opacity over time. RESULTS: Digital retroillumination images were obtained without patient discomfort. Automated analysis of images correlated well with clinical grading both at slit lamp examination and when looking at the images themselves (Spearman's correlation coefficient >0.7). Analysis of images taken at different times showed high reproducibility (intraclass correlation >0.9), and the system was able to identify progression of capsular opacity over a 2-year period with a mean increase of 15.8% in progressors versus an increase of 0.6% in nonprogressors (P < 0.05). CONCLUSIONS: Digital retroillumination images of the posterior capsule can be obtained reliably, and automated analyses correlate well with clinical assessment. The system presented here uses commercially available instruments and software, and it is practical for use in longitudinal studies of posterior capsule opacification. It is reliable, easy to use, and can detect small changes in the percentage area covered by posterior capsule opacification over time.

Cataract↗
PubMed1998

Two kinesin light chain genes in mice. Identification and characterization of the encoded proteins.

Native kinesin consists of two light chains and two heavy chains in a 1:1 stoichiometric ratio. To date, only one gene for kinesin light chain has been characterized, while a second gene was identified in a genomic sequencing study but not analyzed biochemically. Here we describe new genes encoding kinesin light chains in mouse. One of these light chains is neuronally enriched, while another shows ubiquitous expression. The presence of multiple kinesin light chain genes in mice is especially interesting, since there are two kinesin heavy chain genes in humans (Niclas, J., Navone, F., Hom-Booher, N., and Vale, R. D. (1994) Neuron 12, 1059-1072). To assess the selectivity of kinesin light chain interaction with the heavy chains, we performed immunoprecipitation experiments. The data suggested that the light chains form homodimers with no specificity in their interaction with the two heavy chains. Immunofluorescence and biochemical subfractionation suggested differences in the subcellular localization of the two kinesin light chain gene products. Although both kinesin light chains are distributed throughout the central and peripheral nervous systems, there is enrichment of one in sciatic nerve axons, while the other shows elevated levels in olfactory bulb glomeruli. These results indicate that the mammalian nervous system contains multiple kinesin light chain gene products with potentially distinct functions.

Amino Acid Sequence↗
PubMed1998

Assessing disability in the patient with cataract.

Significant progress has been made over the past decade in assessing the functional impact of cataract on patients. Several questionnaires have been shown to predict well the outcomes of cataract surgery. The following article highlights the most recent research in this area and reviews the progress that has been made in the past several years.

Cataract↗