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Biomedical subjects

W Schiff

Publications and source records attributed to W Schiff.

At least 19 recordsLinked to original sources
PubMed2004

Intravitreal triamcinolone for the treatment of refractory diabetic macular oedema with hard exudates: an optical coherence tomography study.

AIM: To investigate the use of intravitreal triamcinolone acetonide (IVTA) for the treatment of diabetic macular oedema (DMO) unresponsive to previous laser photocoagulation. METHOD: A retrospective, interventional, non-comparative case series. There were 30 eyes of 22 consecutive patients with refractory DMO. An intravitreal injection of triamcinolone acetonide at the dose of 4 mg in 0.1 ml was administered. Best corrected visual acuity was measured at each examination. In addition the central macular thickness was quantitatively measured by optical coherence tomography (OCT) examination at each visit. The amount of hard exudates deposition in the macula was subjectively evaluated using colour fundus photographs. RESULTS: 30 eyes of 22 patients completed 6 months or more of follow up and were included in the study. Mean (SD) visual acuity improved from 0.17 (0.12) at baseline to 0.34 (0.18), 0.36 (0.16), and 0.31 (0.17) at the 1, 3, and 6 month follow up respectively. Mean (SD) OCT macular thickness decreased from 476 (98.32) microm at baseline to 277.46 (96.77) microm, 255.33 (95.73) microm, and 331.25 (146.76) microm at the 1, 3, and 6 month follow up period respectively. 18 and seven eyes completed 12 months and 18 months of follow up, respectively. Mean (SD) visual acuity was 0.36 (0.15) and 0.35 (0.16) at the 12 and 18 month follow up period respectively. 12 eyes received two, seven eyes received three, and two eyes received four IVTA injections. The mean (SD) interval between the first and second IVTA injection was 5.7 (2.67) months and between the second and third was 5.7 (3.25) months. Hard exudates were present in the macula at baseline in all eyes. Progressive reduction in the number and size of the hard exudates was noted after IVTA in all cases. Intraocular pressure was raised above 21 mm Hg in 12 (40%) of 30 eyes. Two eyes developed posterior subcapsular cataract and two developed vitreous haemorrhage. CONCLUSIONS: IVTA is a promising treatment for patients with DMO refractory to laser treatment. IVTA is effective in improving vision, reducing macular thickness, and inducing reabsorption of hard exudates. Further investigation is warranted to assess the safety of IVTA for the treatment of DMO.

Adult↗
PubMed1996

Optic coherence tomography of optic disk pit maculopathy.

PURPOSE: To define the structure of optic disk pit maculopathy. METHODS: A patient was examined with optic coherence tomography before and after an intravitreal gas tamponade. RESULTS: Before intravitreal gas injection, optic coherence tomography defined a separation between the inner and outer layers of the retina that connected with the optic disk pit. An outer retinal layer detachment that centered on the fovea was also present. After pneumatic displacement of the intraretinal and subretinal fluid, optic coherence tomography disclosed that the two layers were opposed and in contact with the retinal pigment epithelium. CONCLUSIONS: Optic coherence tomography confirmed the two-layer structure of optic disk pit maculopathy and demonstrated the positive effect of pneumatic displacement.

Humans↗
PubMed1992

Aging persons' estimates of vehicular motion.

Estimated arrival times of moving autos were examined in relation to viewer age, gender, motion trajectory, and velocity. Direct push-button judgments were compared with verbal estimates derived from velocity and distance, which were based on assumptions that perceivers compute arrival time from perceived distance and velocity. Experiment 1 showed that direct estimates of younger Ss were most accurate. Older women made the shortest (highly cautious) estimates of when cars would arrive. Verbal estimates were much lower than direct estimates, with little correlation between them. Experiment 2 extended target distances and velocities of targets, with the results replicating the main findings of Experiment 1. Judgment accuracy increased with target velocity, and verbal estimates were again poorer estimates of arrival time than direct ones, with different patterns of findings. Using verbal estimates to approximate judgments in traffic situations appears questionable.

Acceleration↗
PubMed1990

Accuracy of judging time to arrival: effects of modality, trajectory, and gender.

Observers' accuracy in using time-to-arrival (Ta) information was examined in 4 experiments. The issues included use of visual vs. acoustic Ta information, use of acoustic Ta information by blind Ss, use of Ta information controlling for velocity, and effects of angle of approach and arrival time on judgment accuracy. Visual information was used more efficiently than audiovisual and auditory information. Blind Ss used acoustical approach information as accurately as sighted Ss used visual information. Radial, oblique, and transverse orientations were used to examine effects of approach trajectory. Radial events were underestimated, whereas the more accurate transverse approach was likely to be overestimated. Oblique angle events yielded intermediate accuracies implying a spatiotemporal anisotropy. Women underestimated Ta more than did men. Possible reasons for Ss' judgment accuracy, including linear vs. nonlinear optical changes and relation to spatial skills and experience, were discussed.

Adult↗
PubMed1989

Infant sensitivity to audiovisually coherent events.

We examined 5-month-old infants' sensitivity to audiovisually coherent and incoherent events. A person speaking and an automobile with engine running were filmed approaching and receding with corresponding (coherent) soundtracks. Infants were tested with a habituation paradigm in which they observed coherent or incoherent films, involving, respectively, acoustical radial motion in the direction seen or opposite to the direction seen. Infants habituated to both person and car films, but coherent events uniformly yielded more rapid habituation than did incoherent ones. In addition, infants treated silent events more like audiovisual coherence than like incoherence. Infants habituated more to cars than to people, suggesting that a speaking person may especially maintain infant attention.

Arousal↗
PubMed1986

Recognizing people seen in events via dynamic "mug shots".

This study examined effects of an event and dynamic mug shots on facial recognition. Witnesses saw either a film of a liquor store holdup staged by six perpetrators, slides of the same targets, or freeze-framed views from the filmed event. Slides of different facial views of targets among 12 foils, or dynamic 180 degrees mug shots of the same men, or multiple static views were administered 24 hr later in yes-no recognition tests. Recognition (d') was poorer for the same men seen in the event than in slides, but better for dynamic than for static mug shots. Nondynamic event characteristics were responsible for poor recognition of people seen in events, whereas dynamic aspects of facial transformations, not multiple views, seemed responsible for the superiority of dynamic mug shots. The implications of these results for issues of ecological validity of traditional face recognition methodology and for static feature models vs. dynamic transformation models of face recognition are discussed.

Adult↗
PubMed1980

Does sex make a difference? Gender, age, and stimulus realism in perception and evaluation of aggression.

Judged aggressiveness and its justifiability were examined with caricature cartoons and films of people doing comparable things. Effects of viewer gender, interactant gender, and facial expression were examined. Facial expression strongly affected both types of judgment, viewer gender had no influence, and interactant gender contributed slightly. Real-cartoon differences were significant, but accounted for little variance. Major response patterns were similar for films of people and cartoons. In two developmental studies, only facial expression influenced judgments of friendliness-hostility in cartoons, but condemnation of aggression decreased as viewer age increased. Results with films of real children followed those for cartoons. Facial expression influenced judged aggressiveness, but only viewer age affected judged justifiability. Cross-experiment comparisons revealed that facial expression and the facial expression X real-cartoon interaction yielded major differences on both dependent variables. Subject and interactant gender were not significant for major dependent variables. Results of the developmental studies were similar to adults' suggesting that for judgments of simple aggressive acts, sex makes no difference, but facial expression does make a difference.

Adolescent↗
PubMed1979

Information used in judging impending collision.

Many subhuman species and human infants, children, and adults can use two-dimensional information of relative rate of angular-size change to anticipate collisions between the self and approaching objects or surfaces. But extant studies have not determined what information is used when subjects view simulated approach events providing two-dimensional information and three-dimensional information (distance and distance change), as well as lower-order visual information contained in real approach events. Three experiments suggest that, given these several possibilities, adults' judgments of collision time are best predicted by two-dimensional spatiotemporal values which are invariant over object sizes, distances traversed, approach velocities, and several lower-order variables such as absolute angular size. However, collision time is substantially underestimated, with absolute amount of underestimation increasing as a function of actual time-to-collision. Large constant errors and loss of judgment linearity beyond about 10 s to contact time suggest that current models of human performances based on use of time-to-collision information require modified assumptions of operator efficiency.

Depth Perception↗
PubMed1975

[Is there a risk of transmitting hepatitis by gastroduodenoscopy?].

Among 211 patients undergoing gastroduodenoscopy five had been carriers of Australia antigen. The same instrument had been used on all, and follow-up examination was carried out two and four months after the gastroscopy. Twelve patients died during the follow-up period of their original disease. Two additional patients became Australia-antigen positive. One of these had liver cirrhosis. In the other, surgery with multiple infusions of albumin had been carried out after gastroscopy and could have been the cause of the Australia-antigen transmission. No proven case of hepatitis transmission occurred in this group of patients.

Follow-Up Studies↗