PubMed Health⌕ Search

Biomedical subjects

Bruce Drum

Publications and source records attributed to Bruce Drum.

5 recordsLinked to original sources
PubMed2005

Systematic evaluation of wavefront-guided outcomes.

PURPOSE: To present a format for reporting outcomes of aberrometer-guided refractive procedures. SETTING: SurgiVision Consultants, Inc., Scottsdale, Arizona, and Food and Drug Administration, Center for Devices and Radiological Health, Rockland, Maryland, USA. METHODS: Reports of standard refractive and visual outcomes (uncorrected visual acuity, manifest refractive spherical equivalent, best spectacle-corrected visual acuity) should be provided for any refractive surgery report. Comparison of postoperative uncorrected visual acuity to preoperative best spectacle-corrected visual acuity should be included. Aberration reports should convert 2nd-order terms to refractions (measured in diopters) and use standard refractive reporting methods. Changes in coma, spherical aberration, and root-mean-square changes should be described using statistical methods for aggregate data. Underlying statistics should be reported. RESULTS: Aberration changes are well described by the mean error of the attempted versus achieved outcomes, comparison of the mean changes, and stability over time. Ancillary plots include histogram representation of the postoperative scores. Additional reports of visual function should be included, as appropriate. CONCLUSION: Use of standardized tables and graphs permits qualitative and quantitative comparison of outcomes of refractive treatment with wavefront-guided lasers. Modifications of the recommended formats can be expected over time.

Corneal Surgery, Laser↗
PubMed2005

Response saturation of monochromatic increments on intense achromatic backgrounds: implications for color-opponent organization in human vision.

We present evidence that steady achromatic adapting fields can produce response saturation in color-opponent pathways. We measured tvi (log increment threshold illuminance versus log background illuminance) functions at four test wavelengths (430, 490, 575, and 660 nm) and nine background illuminances from 4.0 to 5.6 log Td. Foveal, 2 degrees diameter, 1 s duration test stimuli were presented on a concentric, perceptually white (5128 degrees K color temperature), 7 degrees diameter, steady background. Thresholds were obtained by the method of adjustment, after which the test stimulus illuminances were increased 0.6 log unit and the subject estimated percentages of red, yellow, green, blue, and white. Average tvi slopes for two subjects were 2.06 for 430 nm, 1.6 for 490 nm, 1.11 for 575 nm and 1.34 for 660 nm, consistent with the estimated ratios of chromatic to achromatic sensitivity at the same wavelengths. Also, the percentage of white seen in the suprathreshold increments increased with increasing background illuminance despite increases in excitation purity. These findings imply that steady, intense, achromatic backgrounds can produce response saturation in color-opponent mechanisms at wavelengths across the visible spectrum. The saturation was more extreme at short wavelengths than at middle or long wavelengths, producing a tritanopic condition at the highest background illuminances. The tritanopia reduced color space to a predominately red-blue dichromacy, in agreement with previous findings. The results support a multistage opponent-color model in which precortical koniocellular and parvocellular opponent pathways interact to produce the observed red-green and yellow-blue color-opponent channels at a cortical level.

Adaptation, Ocular↗
PubMedDate not supplied

FDA regulation of labeling and promotional claims in therapeutic color vision devices: a tutorial.

The Food and Drug Administration (FDA) is responsible for determining whether medical device manufacturers have provided reasonable assurance, based on valid scientific evidence, that new devices are safe and effective for their intended use before they are introduced into the U.S. market. Most existing color vision devices pose so little risk that their manufacturers are not required to submit a premarket notification [510(k)] to FDA prior to market. However, even low-risk devices may not be acceptable if they are marketed on the basis of misleading or excessive claims. Although most color vision devices are diagnostic, two types that are therapeutic rather than diagnostic are colored lenses intended to improve deficient color vision and colored lenses intended to improve reading performance. Both of these devices have presented special regulatory challenges to FDA because the intended uses and effectiveness claims initially proposed by the manufacturers were not supported by valid scientific evidence. In each instance, however, FDA worked with the manufacturer to restrict labeling and promotional claims in ways that were consistent with the available device performance data and that allowed for the legal marketing of the device.

Color Perception↗
PubMedDate not supplied

Standardized analyses of correction of astigmatism by laser systems that reshape the cornea.

PURPOSE: To develop a minimum set of analyses and a format for presentation of outcomes of astigmatism correction by laser systems that reshape the cornea. METHODS: An Astigmatism Project group was created under the auspices of the American National Standards Institute (ANSI) Z80.11 Working Group on Laser Systems for Corneal Reshaping. The Astigmatism Project Group was made up of experts in astigmatism analyses from academia, government, and industry. An extensive literature review was conducted to identify all currently available methodologies for the evaluation of astigmatic outcomes. Project Group members discussed the utility of each method and its specific parameters for evaluating the effectiveness of astigmatism-correcting devices. They gave consideration to unique terminology and analyses required for evaluation of correction of astigmatism by laser systems that reshape the comea. RESULTS: The Project Group defined a comprehensive list of analysis variables needed for the evaluation of astigmatism-correcting devices and generated a mathematical definition for each term. They developed a minimum set of analyses needed for evaluation of astigmatism treatments by laser systems that reshape the cornea. They established methods for calculating the refractive error analysis variables and constructed recommended table and graph formats for data presentation. CONCLUSIONS: This article contains the recommendations of the Astigmatism Project Group of the American National Standards Institute. We propose it as a standard reference for astigmatic refractive error analyses for the evaluation of safety and effectiveness of laser systems that reshape the cornea.

Astigmatism↗