Computerized color-vision test based upon postreceptoral channel sensitivities.

An automated, computerized color-vision test was designed to diagnose congenital red-green color-vision defects. The observer viewed a yellow appearing CRT screen. The principle was to measure increment thresholds for three different chromaticities, the background yellow, a red, and a green chromaticity. Spatial and temporal parameters were chosen to favor parvocellular pathway mediation of thresholds. Thresholds for the three test stimuli were estimated by four-alternative forced-choice (4AFC), randomly interleaved staircases. Four 1.5-deg, 4.2 cd/m2 square pedestals were arranged as a 2 x 2 matrix around the center of the display with 15-minute separations. A trial incremented all four squares by 1.0 cd/m2 for 133 ms. One randomly chosen square included an extra increment of a test chromaticity. The observer identified the different appearing square using the cursor. Administration time was approximately 5 minutes. Normal trichromats showed clear Sloan notch as defined by log (deltaY/deltaR), whereas red-green color defectives generally showed little or no Sloan notch, indicating that their thresholds were mediated by their luminance system, not by the chromatic system. Data from 107 normal trichromats showed a mean Sloan notch of 0.654 (SD = 0.123). Among 16 color-vision defectives tested (2 protanopes, 1 protanomal, 6 deuteranopes, & 7 deuteranomals), the Sloan notch was between -0.062 and 0.353 for deutans and was < -0.10 for protans. A sufficient number of color-defective observers have not yet been tested to determine whether the test can reliably discriminate between protans and deutans. Nevertheless, the current data show that the test can work as a quick diagnostic procedure (functional trichromatism or dichromatism) of red-green color-vision defect.

Wound complications after hip surgery using a tapeless compressive support.

PURPOSE: To compare the incidence of wound complications after hip surgery in patients treated with a compressive spica wrap dressing to those using traditional taping methods. DESIGN: Retrospective, descriptive, comparative, intervention study. SAMPLE: 457 hip surgery patients, including primary arthroplasty, revision surgery and fracture with ORIF. METHOD: A compressive wrap dressing was used on hip surgery patients in the study group while tape was used on patients in the control group. A retrospective chart review was conducted noting postoperative wound complications. FINDINGS: There was a significantly lower incidence of blisters and drainage in the study group using a compressive wrap dressing. There was not a higher incidence of DVT or infection using the wrap dressing when compared to published studies. CONCLUSION: Use of a compressive wrap dressing after hip surgery is recommended to reduce the risk of wound complications. IMPLICATIONS FOR NURSING RESEARCH: A prospective, randomized study with multiple surgeons using both compressive wraps and traditional taping techniques would substantiate the advantage of using a hip spica dressing after hip surgery.