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PubMed1996

Computer use in schools for the blind in Japan.

In a school for the blind, computer use and feelings toward computers by 34 visually impaired students receiving secondary education and by their 42 teachers were investigated with a questionnaire. Most subjects used computers effectively, but some students who had low vision did not wish to use them to avoid strain on their eyes. The computers allowed use of Kanji (Chinese characters) by the blind students, providing a new tool in their learning of Kanji. In classes, it is necessary to maintain and customize the computers continuously.

Adolescent↗
PubMed1989

Stereausis: binaural processing without neural delays.

A neural network model is proposed for the binaural processing of interaural-time and level cues. The two-dimensional network measures interaural differences by detecting the spatial disparities between the instantaneous outputs of the two ears. The network requires no neural delay lines to generate such attributes of binaural hearing as the lateralization of all frequencies, and the detection and enhancement of noisy signals. It achieves this by comparing systematically, at various horizontal shifts, the spatiotemporal responses of the tonotopically ordered array of auditory-nerve fibers. An alternative view of the network operation is that it computes approximately the cross correlation between the responses of the two cochleas by combining an ipsilateral input at a given characteristic frequency (CF) with contralateral inputs from locally off-CF locations. Thus the network utilizes the delays already present in the traveling waves of the basilar membrane to extract the correlation function. Simulations of the network operation with various signals are presented as are comparisons to computational schemes suggested for stereopsis in vision. Physiological arguments in support of this scheme are also discussed.

Artificial Intelligence↗
PubMed1965

EVOKED POTENTIALS AND CORRELATED JUDGEMENTS OF BRIGHTNESS AS FUNCTIONS OF INTERFLASH INTERVALS.

Computer-averaged evoked potentials were recorded from subjects presented with pairs of flashes having equal light energy but differing in duration of the brief interval separating the flashes. For the experimental conditions studied, the pair was always subjectively fused. Although the brightness did not change noticeably as the interval was varied, the use of the forced-choice psychophysical technique showed that apparent brightness declined with increase in the interval. Analysis of the evoked potentials revealed a correlated change in amplitude and wave form previously demonstrated for changes in flash flux alone.

Computers↗
PubMed1987

Some task and signal dependent rules for spatial vision.

In this paper we consider the types of computational processes which may be involved in solving a variety of perceptual problems from the detection of signals in the presence of others, to texture discrimination, and some aspects of pattern recognition. These processes centre around the involvement of correlational computations, the transduction of their input/output values, and the apparent involvement of selective filtering mechanisms. Our results suggest that even if fixed detectors (in tuning characteristics) are involved in low-level vision, the human observer apparently employs much more adaptive (variable tuning characteristic) filters and nonlinear mechanisms in more complex spatial tasks.

Humans↗
PubMedDate not supplied

[Use of liquid crystal eyeglasses for examination and recovery of binocular vision].

A new method for diploptic treatment of strabismus is proposed, based on phase division of visual fields using liquid crystal eyeglasses --computer complex. The method is based on stereovision training (allowing stereothreshold measurements up to 150 ang. sec.). The method was tried in examinations of two groups of children: 10 controls and 74 patients with strabismus. Examinations of normal controls gave new criteria for measuring fusion reserves and stereovisual acuity by the proposed method. The therapeutic method was tried in 2 groups of patients. Time course of visual function improvement was followed up by several criteria: changes in binocular status by the color test and improvement of in-depth and stereoscopic visual acuity. The method is recommended for practice. The authors discuss the problem of small angle strabismus.

Child↗
PubMed1990

[Automated examination methods in ophthalmology].

Following logical step-by-step strategies, many ophthalmological examinations are based on relatively simple methods. Because of this modern computers are capable of monitoring many of these examinations and of measuring the data. The interpretation, however, must be done by an ophthalmologist who can then relate the results to the patient's vision.

Diagnosis, Computer-Assisted↗
PubMed2002

The efficacy of computer glasses in reduction of computer worker symptoms.

BACKGROUND: Computer workers with presbyopia are at greater risk for the development of symptoms with a conventional prescription vs. a computer prescription because general-wear multi-focal corrections often do not provide adequate correction for the viewing distances and angles needed at the computer workstation. "Computer glasses," as defined by the American Optometric Association, are specifically designed for the computer workplace and have a different lens design or prescription than general-wear glasses. The purpose of this study is to evaluate the effectiveness of computer glasses in reduction of symptoms of presbyopic computer users. METHODS: Subjects were 26 symptomatic presbyopic computer users who had had an eye examination within the past year and had 20/20 vision at distance and near with habitual glasses. Two interventions in planned alternating order were tested for 3 weeks each on all subjects. One intervention was computer glasses. The comparison intervention was an ergonomic self-assessment tool (ESAT) with their habitual Rx. Symptoms were assessed before and after each intervention. A post-comparative questionnaire asked subjects to reflect on the relative efficacy and ease of use of the two interventions. RESULTS: The computer glasses were significantly more effective at reducing the frequency and severity (p < 0.008) of the symptoms than the ESAT, and 24 of 26 subjects judged the computer glasses to bemore effective. Subjects attributed 80.7% of symptom reduction to the computer glasses and 19.3% to the ESAT. Although the ESAT was judged effective, it was not as effective as the computer glasses. CONCLUSION: Computer glasses have been shown to be effective in reduction of vision-related symptoms of computer users.

Computers↗
PubMed1997

Top-down learning of low-level vision tasks.

Perceptual tasks such as edge detection, image segmentation, lightness computation and estimation of three-dimensional structure are considered to be low-level or mid-level vision problems and are traditionally approached in a bottom-up, generic and hard-wired way. An alternative to this would be to take a top-down, object-class-specific and example-based approach. In this paper, we present a simple computational model implementing the latter approach. The results generated by our model when tested on edge-detection and view-prediction tasks for three-dimensional objects are consistent with human perceptual expectations. The model's performance is highly tolerant to the problems of sensor noise and incomplete input image information. Results obtained with conventional bottom-up strategies show much less immunity to these problems. We interpret the encouraging performance of our computational model as evidence in support of the hypothesis that the human visual system may learn to perform supposedly low-level perceptual tasks in a top-down fashion.

Algorithms↗
PubMed1999

Eye movement control in reading: accounting for initial fixation locations and refixations within the E-Z Reader model.

Reilly and O'Regan (1998, Vision Research, 38, 303-317) used computer simulations to evaluate how well several different word-targeting strategies could account for results which show that the distributions of fixation locations in reading are systematically related to low-level oculomotor variables, such as saccade distance and launch site [McConkie, Kerr, Reddix & Zola, (1988). Vision Research, 28, 1107-1118]. Their simulation results suggested that fixation locations are primarily determined by word length information, and that the processing of language, such as the identification of words, plays only a minimal role in deciding where to move the eyes. This claim appears to be problematic for our model of eye movement control in reading, E-Z Reader [Rayner, Reichle & Pollatsek (1998). Eye movement control in reading: an overview and model. In G. Underwood, Eye guidance in reading and scene perception (pp. 243-268). Oxford, UK: Elsevier; Reichle, Pollatsek, Fisher & Rayner (1998). Psychological Review, 105, 125-157], because it assumes that lexical access is the engine that drives the eyes forward during reading. However, we show that a newer version of E-Z Reader which still assumes that lexical access is the engine driving eye movements also predicts the locations of fixations and within-word refixations, and therefore provides a viable framework for understanding how both linguistic and oculomotor variables affect eye movements in reading.

Eye Movements↗
PubMed2005

Active vision and receptive field development in evolutionary robots.

In this paper, we describe the artificial evolution of adaptive neural controllers for an outdoor mobile robot equipped with a mobile camera. The robot can dynamically select the gazing direction by moving the body and/or the camera. The neural control system, which maps visual information to motor commands, is evolved online by means of a genetic algorithm, but the synaptic connections (receptive fields) from visual photoreceptors to internal neurons can also be modified by Hebbian plasticity while the robot moves in the environment. We show that robots evolved in physics-based simulations with Hebbian visual plasticity display more robust adaptive behavior when transferred to real outdoor environments as compared to robots evolved without visual plasticity. We also show that the formation of visual receptive fields is significantly and consistently affected by active vision as compared to the formation of receptive fields with grid sample images in the environment of the robot. Finally, we show that the interplay between active vision and receptive field formation amounts to the selection and exploitation of a small and constant subset of visual features available to the robot.

Artificial Intelligence↗
PubMedDate not supplied

Computed tomography in ethmoid cell trauma.

Clinical and radiological evaluation of 19 patients with injury to the ethmoid bones following cranio-facial trauma is presented. The correlation of ethmoid trauma and damage to neighbouring structures is discussed. Two cases with damage to the orbits are demonstrated. These findings indicate that orbital involvement is relatively infrequent in association with ethmoid cell trauma. However, when it does occur, severe complications, such as infection and loss of vision may result. Early evaluation by computed tomography is the key to accurate diagnosis and prevention of these complications. Computed tomography is of inestimable value in the detection of minute and subtle bone fragmentation and sequelae.

Adolescent↗
PubMed1995

Is there a typical VDT patient? A demographic analysis.

BACKGROUND: The use of video display terminals (VDT) in the workplace is growing rapidly. Visual problems associated with computer use are increasing apace. Recognizing and addressing these needs are vital tasks for the optometric practitioner. This paper examines the demographics, prevalence of symptoms, and other work- and vision-related factors among VDT workers. Understanding the characteristics of a typical patient can aid in developing effective treatment protocols. METHODS: Twenty-two optometrists collected data from 324 patients who work on VDT screens for a minimum of 2 hours per day. A questionnaire was used to collect the data. Along with reporting the patients' dry manifest refraction results, the survey instrument also included a self-report of experienced symptoms. RESULTS: The prototypical patient, based on the total subject population, is a 38-year old, mildly myopic female who uses the computer screen about 5 hours per day. Average total VDT work experience is about 5 years. Most of the patients use full-color screens and sit between 21 and 22 inches away from the screen. A variety of visual symptoms is reported, with eyestrain (65 percent) and headaches (42 percent) being the most common complaints. CONCLUSIONS: Between 75 percent (results of this study) and 88 percent (reported by NIOSH) of patients who use a VDT regularly are likely to be symptomatic. This study has helped to identify the "typical" VDT user and the symptoms this user is most likely to report. The next step is to develop a diagnostic and treatment protocol by which optometrists can prescribe for and potentially prevent these computer-related vision problems.

Adolescent↗
PubMed1978

Computer assisted monitoring in intensive medicine.

Intensive Medicine is always associated with the problem of handling the mass and assuring the quality of information on vital signs, fluid and blood balance, laboratory data, physiological calculations, etc., required in patient care. A computer based monitoring system for intensive care was introduced in 1973 at the Academic Hospital in Leuven. The basic software was developed at the Peter Bent Brigham Hospital of the Harvard Medical School and the medical division of the Hewlett Packard Company; the computer used was a H.P. 2100 central processor with 32K of core memory. Initially, the program allowed mainly acquisition, storage and retrieval of bedside monitored and manual data of cardiac and circulatory function. Very soon however, the software was extended and modified by the division of "Medical Informatics" in order to meet new or different requirements. In the present situation our vision on the use of computer-assisted monitoring has changed and our present program has been extended as follows : 1. On-line collection and retrieval of bedside monitored data including heart rate, arterial blood pressure (systolic-diastolic-mean) left atrial pressure, central venous pressure, pulmonary artery pressure, intracranial pressure. Trend analysis of those data, with calculation of mean values, standard variation and corresponding t-tests. 2. Computer assistance in performing time consuming calculations on off-line data such as : -- clearance-values (renal function), -- temperature-correction of blood-gasvalues, -- hour-to-hour fluid balance, including calculation of in-sensible losses, -- blood-balance. 3. Data transmission of laboratory results as soon as available in the central laboratory through a direct link between laboratory and I.T.U. 4. Computer assisted E.C.G. analysis. The three first objectives are realised, on-line E.C.G.-analysis is being developed. The same computer serves the remotely located medical and coronary care units and one bed in the emergency department. An assessment of computer assistance in intensive therapy, on nursing labor and on quality of patient care is made.

Clinical Laboratory Techniques↗
PubMed2002

Optic nerve sheath meningiomas: visual improvement after stereotactic radiotherapy.

OBJECTIVE: The management of primary optic nerve sheath meningioma (ONSM) is controversial. Surgery often results in postoperative blindness in the affected eye and thus has been abandoned as a treatment option for most patients. When these tumors are left untreated, however, progressive visual impairment ensues, which also leads to blindness. Recently, radiation therapy has gained wider acceptance in the treatment of these lesions. Experience with stereotactic radiotherapy (SRT) in the treatment of ONSMs is limited because of the rare incidence of this tumor. We present a series of patients with ONSM who were treated with SRT. METHODS: Five patients (three women, two men), ranging in age from 40 to 73 years, presented with progressive visual loss with decreased visual field, visual acuity, and color vision affecting six eyes (one patient had tumor involving both optic nerves). One patient also presented with proptosis and diplopia. Five eyes had functional residual vision (range, 20/20 to 20/40), and one eye was completely blind. All five patients were diagnosed clinically and radiographically to have an ONSM. Three were intraorbital, one was intracanalicular as well as intraorbital, and one was a left ONSM extending through the optic foramen into the intracranial space and involving the right optic nerve. The five functional eyes were treated with SRT by use of 1.8-Gy fractions to a cumulative dose of 45 to 54 Gy. RESULTS: Follow-up ranged from 1 to 7 years, and serial magnetic resonance imaging revealed no changes in the size of the tumor in all five patients. Four patients experienced dramatic improvement in visual acuity, visual field, and color vision within 3 months after SRT. One patient remained stable without evidence of visual deterioration or disease progression. None had radiation-induced optic neuropathy. CONCLUSION: SRT may be a viable option for treatment of primary ONSM in patients with documented progressive visual deterioration, and it may be effective in improving or stabilizing remaining functional vision.

Adult↗