Biomedical subjects

Barbara S Hawkins

Publications and source records attributed to Barbara S Hawkins.

21 records · Page 2Linked to original sources

PubMed2003

Measurement and analysis of visual acuity in multicenter randomized clinical trials in the United States: findings from a survey.

PURPOSE: To describe visual acuity (VA) testing and scoring methods used in multicenter randomized clinical trials in ophthalmology in the United States (USA) sponsored by the National Eye Institute (NEI). METHODS: A survey was conducted among multicenter studies in the US that included one or more randomized clinical trials and were sponsored by the NEI, National Institutes of Health. To be included in the survey, a study had to have VA reported in one or more publications or patient eligibility based on VA, a majority of study subjects 13 years of age or older, and a patient population primarily or exclusively from the US. A standard survey form was completed for each study based on information presented in the study manual of procedures and publications. Findings were summarized and displayed with frequency distributions. RESULTS: The survey included 24 studies, each with enrollment initiated in the period 1972 to 1999. VA was one of the study eligibility criteria for 19 (79%) studies, and VA or change in VA was the primary outcome in 12 (50%) studies. ETDRS charts have been employed in 16 of 19 studies initiated after the charts were published in 1982. All studies but one specified in the documents reviewed that VA testing was performed at multiple VA test distances. For studies that used ETDRS charts, methods of converting VA scores obtained at different test distances to a common scale fell into two categories: 11 studies used a method similar in nature to that first reported in the Macular Photocoagulation Study, and 7 studies used a method similar in nature to that first reported in the Krypton-Argon Regression of Neovascularization Study. conclusion The development of the ETDRS charts and a custom light box has led to more uniformity in VA test charts and chart illumination. However, details of VA measurement protocols vary widely from study to study. To assure comparable data across studies and ocular conditions, it would be useful to have a standard VA testing and scoring protocol with provisions for testing different levels of visual acuity that recommends a single method for converting scores from different test distances to a common scale and standard conversion of "off the chart" VA levels for calculation of means and changes in VA.

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PubMed2002

Consistency between visual acuity scores obtained at different test distances: theory vs observations in multiple studies.

OBJECTIVE: To investigate the consistency of visual acuity (VA) scores measured at 2 different distances in patients with or at risk for choroidal neovascularization. METHODS: Best-corrected VA scores measured at 2 distances for the same eyes at the same examinations were collected from 4 sets of randomized clinical trials among patients with or at risk of choroidal neovascularization. Within each trial, the pairs of VA scores were compared and their relationship was explored. RESULTS: After adjustment for test distance, VA scores obtained at the closer distance were found to be systematically lower than those obtained at the farther distance in all data sets. In the Submacular Surgery Trials pilot study, the average discrepancy between 2- and 0.5-m VA scores was 7.5 letters. In an ancillary study of the Macular Photocoagulation Study, the discrepancy between 10-ft and 5-ft VA scores was 3.1 letters. In the Laser to Drusen Trial pilot study, the discrepancy between 3.2- and 1-m VA scores was 7.3 letters. In the Treatment of Age-Related Macular Degeneration With Photodynamic Therapy Study, in which the VA scores at the closer test distance were censored, the estimated discrepancy between 2- and 1-m VA scores was 8.2 letters. Reduction in visual angle at closer test distance did not explain the discrepancy completely. Features of the macular lesion, poor accommodation of the elderly population with age-related macular degeneration, or the test charts did not account for the discrepancies. CONCLUSION: The VA scores at distances less than 2 m were lower than expected in all 4 studies. The observed discrepancy was consistent with findings from a study among healthy young subjects, suggesting that the phenomenon is real and common.

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PubMedDate not supplied

Guidelines for interpreting retinal photographs and coding findings in the Submacular Surgery Trials (SST): SST report no. 8.

PURPOSE: To describe the guidelines followed by the Submacular Surgery Trials (SST) Research Group in the interpretation of color fundus photographs and fluorescein angiograms of subfoveal choroidal neovascular lesions evaluated in the SST and to assist ophthalmologists in applying the results of the SST. METHODS: Stereoscopic color fundus photographs and fluorescein angiograms of the study eye and nonstudy eye of 1,015 patients with subfoveal choroidal neovascular lesions secondary to age-related macular degeneration, ocular histoplasmosis syndrome, or idiopathic choroidal neovascularization (CNV) were obtained and graded by certified SST fundus photograph readers at the baseline examination in three randomized clinical trials comparing surgery with observation. Adherence to the inclusion and exclusion criteria and ocular features that might affect visual outcome were documented. Stereoscopic color fundus photography and fluorescein angiography were repeated 1 month after randomization for patients assigned to surgery to provide documentation that surgery was performed and to assess compliance with the surgery protocol. Photographs and fluorescein angiograms of both the study eye and the fellow eye in all patients then were obtained 3 months, 6 months, and 12 months after randomization and then annually up to 48 months. The kappa statistic was used to evaluate interobserver reliability of photograph gradings. RESULTS: Lesion components at baseline included classic CNV, occult CNV, and features contiguous to CNV, including blood, fibrous tissue, hypofluorescence not corresponding to blood, serous detachment of the retinal pigment epithelium, and prior areas of laser photocoagulation. At follow-up, fluorescein leakage from CNV was assessed peripheral to or within the area of the retinal pigment epithelium abnormality after surgery. The lesion at follow-up could include any of the features identified at baseline as well as retinal pigment epithelium abnormalities, such as mottling of the retinal pigment epithelium with a subtle transition to normal retinal pigment epithelium or a very sharply demarcated, markedly hypopigmented area that was easily distinguished from the surrounding retinal pigment epithelium. kappa statistics for interobserver reliability ranged from good (0.47) to excellent (1.00) for features graded at baseline and follow-up. CONCLUSIONS: Although some of the definitions essential to the interpretation of the SST are similar to those used in the Macular Photocoagulation Study and randomized clinical trials of photodynamic therapy with verteporfin, this guideline provides new information regarding lesion components at baseline as well as standardized descriptions of lesions after submacular surgery. These descriptions from the SST assist in understanding what lesions were studied, when additional treatment was considered after surgery, and how anatomical results should be interpreted.

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