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At least 1,459 records · Page 81Linked to original sources
PubMed2002

Impact of graphical user interface screen features on computer task accuracy and speed in a cohort of patients with age-related macular degeneration.

PURPOSE: To investigate the impact of graphical user interface screen features on computer task performance in patients with age-related macular degeneration (AMD). DESIGN: Interventional case series. METHODS: Eighteen patients with visual impairment due to AMD were recruited from the Bascom Palmer Eye Institute Low Vision Clinic. Each patient underwent evaluation of visual acuity using the Early Treatment Diabetic Retinopathy Study protocol, contrast sensitivity using a Pelli-Robson chart, binocular simultaneous visual field using the Esterman program on an automated perimeter, and color vision using Farnsworth D-15. Each subject then completed computer icon identification tasks while the following screen features of the graphical user interface were varied: size of icons displayed, icon set size (number of icons displayed), and background color. Each patient performed all 125 computer tasks with each of five icon sizes (9.2 mm, 14.6 mm, 23.2 mm, 36.8 mm, 58.3 mm), each of five icon set sizes (2, 3, 4, 5, 6), and each of five different background colors (black, white, red, green, blue) in a randomly ordered fashion. Relationships between computer task performance (accuracy and speed) and graphical user interface screen features were studied. RESULTS: Icon size and icon set size are significantly associated with computer task accuracy (P <.001), whereas background color is not a significant predictor of task accuracy (P =.63). The impact of icon size on accuracy is nonlinear, with the data indicating that no additional improvement in accuracy is associated with increasing the icon size beyond 23.2 mm. The impact of icon set size on accuracy is linear, with a smaller icon set size significantly associated with greater computer accuracy. A larger icon size is significantly associated with a shorter time to task completion (P =.001); this relationship is largely linearly related to icon size. There was no significant impact of background color (P =.11) or set size (P =.37) on time to task completion. CONCLUSIONS: Modifications of graphical user interface design may permit improved computer task performance among patients with visual impairment due to AMD.

Adult↗
PubMed2003

Tension pneumocyst after transsphenoidal surgery for Rathke's cleft cyst: case report.

OBJECTIVE AND IMPORTANCE: Tension pneumocephalus is a rare but well-described complication of transsphenoidal surgery. It is usually associated with postoperative cerebrospinal fluid fistulae causing lower intracranial pressure, with air located in the subdural, subarachnoid, or intraventricular space. We report a case of suprasellar tension pneumocyst that caused visual deterioration to develop after an operation for a Rathke's cleft cyst. Only one similar case has been reported previously. CLINICAL PRESENTATION: A 54-year-old woman with a cystic sellar-suprasellar mass compressing the chiasm was operated on via a standard transsphenoidal approach. The intraoperative diagnosis was Rathke's cleft cyst, and the floor of sella was left open to avoid recurrence. The sphenoid sinus was filled with a fat graft, and the rostrum of the sphenoid was reconstructed with a bone fragment. The patient's postoperative course was uneventful, and her vision improved. Ten days after discharge, the patient was readmitted to the emergency service with headache and visual impairment. Emergent computed tomography confirmed a suprasellar tension pneumocyst. INTERVENTION: The patient underwent immediate reoperation via an endonasal endoscopic approach. After the trapped air was evacuated, the sella was closed with fascia lata and muscle using fibrin glue. The patient's vision improved postoperatively. CONCLUSION: Suprasellar tension pneumocyst is an extremely rare complication of transsphenoidal surgery. To avoid this complication, the sellar floor should be repaired in a watertight fashion, and patients should be instructed to avoid blowing the nose, sneezing, straining, and coughing postoperatively.

Central Nervous System Cysts↗
PubMed2002

Impact of visual function on computer task accuracy and reaction time in a cohort of patients with age-related macular degeneration.

PURPOSE: To investigate the impact of visual function parameters on computer task performance in patients with age-related macular degeneration (AMD). DESIGN: Interventional case series. METHODS: Eighteen patients with visual impairment due to age-related macular degeneration underwent evaluation of visual acuity using the Early Treatment Diabetic Retinopathy Study protocol, contrast sensitivity using a Pelli-Robson chart, binocular simultaneous visual field using the Esterman program on an automated perimeter, and color vision using Farnsworth D-15. Each subject then completed 125 computer icon identification tasks. Relationships between computer task performance (accuracy and speed) and visual function parameters (visual acuity, contrast sensitivity, visual field, and color vision) were analyzed. RESULTS: Visual acuity and contrast sensitivity in the better eye, weighted average contrast sensitivity, and color vision defects are significantly associated with computer task accuracy. Visual acuity in the better eye, weighted average visual acuity, and color vision defects are significantly associated with performance speed. Visual function parameters and clinical features significantly associated with computer task accuracy in a multiple regression model include weighted average contrast sensitivity (P = 0.001), protan color vision defect (P = 0.002), cataract severity in the better-seeing eye (P = 0.036), and geographic atrophy outside the central macula (P = 0.046). Visual function parameters and clinical features significantly associated with computer task speed in a multiple regression model include color vision defects (deutan, P < 0.001; protan, P < 0.001) and gender (P = 0.05). CONCLUSIONS: Among this cohort of patients with AMD, visual acuity, contrast sensitivity, and color vision defects are significant predictors of computer task performance. Visual function parameters of the better eye played a more significant role than parameters of the worse eye, and contrast sensitivity is the most significant predictor of computer task accuracy.

Activities of Daily Living↗
PubMedDate not supplied

[The examination of color vision using a 2 metameric equation method].

Modern anomaloscopes with four independent light channels (i.e. Besançon-Anomalometer which was presented in 1979 at the SFO Congress) allow accurate examinations of color vision. In our routine clinical examination, we use two metameric equations: the red-green Rayleigh equation and the blue-green Moreland equation. This so called Two-Equation-Method enables the diagnosis of congenital and acquired color vision defects in a precise qualitative as well as quantitative way. For both equations the goal of the examination is to measure the absolute matching range. Abnormal color vision is diagnosed if the absolute matching range is shifted and/or enlarged in one or both of the two metameric equations. In congenital colour vision deficiencies, the results are similar to those obtained with the Nagel anomaloscop. The different types of acquired defects are compared with the types of Verriest's classification. A computer controlled clinical examination of color vision, which will make the procedure simplier and shorter for the patient is actually being developed.

Color Perception↗
PubMed2005

The extended Maxwellian view (BIGMAX): a high-intensity, high-saturation color display for clinical diagnosis and vision research.

We describe a device that can display very high intensity (up to 400,000 cd/m2), high-resolution visual stimuli. The device is inexpensive, is easily controlled by a conventional computer and video card, and can be calibrated for use in vision research or clinical applications. The display is capable of presenting highly saturated, near spectral colors. Unlike Maxwellian view optical systems, our display can be viewed binocularly and does not require exacting head restraint. We describe the construction, give a design example, and describe our calibration procedure. Furthermore, we report measurements of the color gamut, spatial resolution, temporal characteristics, and the dynamic range of light intensity.

Computer Graphics↗
PubMed1998

Coronary artery surgery: the end of the beginning.

In each of the first three decades of myocardial revascularization, conventional treatment has been revised completely. This lecture comments on three areas of discovery that have shaped the evolution of myocardial revascularization: science, technology development, and revascularization. The discoveries in all three areas are inexorably interrelated. The single greatest lesson learned so far is that conduit performance carries more prognostic weight than any other factor. We have observed that vein graft atherosclerosis is predictable, and that the first-generation lipid lowering drugs have a favorable effect in patients who achieve marked LDL reduction. Biologically better revascularization begins with use of the internal thoracic artery for grafting to the anterior descending coronary artery. As the results of internal thoracic artery grafting are widely reported, arterial bypass revascularization has expanded, notably by radial and gastroepiploic arteries. The results of bilateral internal thoracic artery grafting are discussed, including large-scale registry results of internal thoracic artery usage in the United States. The internal thoracic artery is significantly underutilized. Diabetes affects both endoluminal and surgical revascularization. The new pharmacology in cardiology interventions shows promise in diminishing restenosis and thrombosis even in diabetic patients. Conversely, extended internal thoracic artery grafting may also benefit diabetic patients. Now we are entering a new age of minimally invasive coronary surgery. We have passed through the early stages of mini-thoracotomy, and we are moving on to access through 1-cm ports, intrathoracic cannulation, antegrade and retrograde myocardial protection, and computer guided three-dimensional vision and instrumentation. The potential for robotic control adds greater precision, ease of use, and safety. This new technology will be integrated with diagnostic information, intraoperative monitoring, anesthesia and perfusion data, cost accounting, and surgical note transcription. The operating room of the future will package intraoperative information and is adaptable to all surgical specialties. The future of coronary artery surgery will depend on minimally invasive techniques, all-arterial grafting, and selective lipid modification to reduce progressive atherosclerosis. The conclusion of this decade marks the end of the beginning. The new generation of cardiothoracic surgeons will share in an array of technology and research unmatched in previous decades.

Coronary Artery Disease↗
PubMed1992

Cerebral amyloid angiopathy with granulomatous angiitis ameliorated by steroid-cytoxan treatment.

We report a case of a 62-year-old black woman who, 8 months prior to death, developed confusion, apraxias, disorientation, and difficulties with her vision. There was no dementia. Computed tomography (CT) scan and magnetic resonance imaging (MRI) suggested a tumor in the right posterior parietal white matter. A biopsy of the lesion displayed granulomatous angiitis and severe cerebrovascular amyloidosis, but no tumor was identified. Chronic inflammation with an occasional multinucleated giant cell was seen about the amyloid-infiltrated vessels. The cortex demonstrated gliosis but no plaques or tangles. Subsequently, the patient was treated with steroids and Cytoxan, with an improvement in her neurologic status. She died of opportunistic bronchopneumonia 8 months after the initial onset of her symptoms. On postmortem examination, the biopsied area of the brain showed atrophy with gliosis. Amyloid angiopathy was present but in much lesser degree than in the biopsy. Scant perivascular inflammatory infiltrates were seen only focally, and no giant cells were observed. The amyloid, both in the biopsy and autopsy material, was of the Alzheimer A4 type. This case suggests that steroid and cytoxan treatment ameliorated the angiitis and the amyloid angiopathy as well. The pertinent literature is discussed.

Cerebral Amyloid Angiopathy↗
PubMed2000

An imaging system with calibrated color image acquisition for use in dermatology.

We propose a novel imaging system useful in dermatology, more precisely, for the follow-up of patients with an increased risk of skin cancer. The system consists of a Pentium PC equipped with an RGB frame grabber, a three-chip charge coupled devices (CCD) camera controlled by the serial port and equipped with a zoom lens and a halogen annular light source. Calibration of the imaging system provides a way to transform the acquired images, which are defined in an unknown color space, to a standard, well-defined color space called sRGB. sRGB has a known relation to the CIE1 XYZ and CIE L*a*b* colorimetric spaces. These CIE color spaces are based on the human vision, and they allow the computation of a color difference metric called CIE deltaE*ab, which is proportional to the color difference, as seen by a human observer. Several types of polynomial RGB to sRGB transforms will be tried, including some optimized in perceptually uniform color spaces. The use of a standard and well-defined color space also allows meaningful exchange of images, e.g., in teledermatology. The calibration procedure is based on 24 patches with known color properties, and it takes about 5 minutes to perform. It results in a number of settings called a profile that remains valid for tens of hours of operation. Such a profile is checked before acquiring images using just one color patch, and is adjusted on the fly to compensate for short-term drift in the response of the imaging system. Precision or reproducibility of subsequent color measurements is very good with (deltaE*ab) = 0.3 and deltaE*ab < 1.2. Accuracy compared with spectrophotometric measurements is fair with (deltaE*ab) = 6.2 and deltaE*ab < 13.3.

Calibration↗
PubMed1994

Sketching the future: trends influencing nursing informatics.

Technologies emerging in the fields of telecommunications, video and digital imaging, and microprocessing are shaping the future of nursing practice. To measure up to the future needs of nursing, nurses of today must have the vision and desire to become computer aware and technologically literate. Hypothetical future situations pose challenges related to current nursing informatics and artificial intelligence issues. Discussion includes technology issues related to the lifetime clinical health record. Areas that the Center for Nursing Research considers priorities for informatics suggest directions for nursing technology efforts. This article calls on all nurses to become active in designing and molding future clinical practice systems.

Computer Literacy↗
PubMed1991

Recurrent mixed tumor of the right lacrimal gland causes acute contralateral visual loss.

A 23-year-old woman underwent excisional biopsy of a right palpebral mass: the histopathologic study showed a benign mixed tumor of the lacrimal gland. Thereafter, the tumor recurred repeatedly, and multiple excisions were done. Subsequently, right orbital exenteration was performed, and some orbital and frontal bones were removed. When the patient was 52 years old, the orbital tumor recurred. A histopathologic study revealed malignant transformation. At the age of 54 years, the patient suffered acute loss of vision in her left eye. Computed tomography disclosed invasion of the tumor into the posterior paranasal sinuses and brain.

Adenoma↗
PubMed2002

Rotational remapping in human spatial memory during eye and head motion.

The brain uses vision and other senses to compute the locations of objects relative to the body, and then must update these locations when the body moves. How geometrically sophisticated is this internal updating? It has been suggested that updating simply shifts the stored locations of all objects uniformly, by a common vector, when the eye or head turns. For horizontal and vertical turns, a uniform shift would often approximate the real changes in location of objects in front of the subject. But for torsional rotations, a shift would be inadequate: accurate updating would call for a more geometrically exact remapping, not shifting but rotating the stored locations through the inverse of the rotation of the eye in space. Here we asked human subjects to make eye saccades to remembered targets after torsional head rotations. Their accuracy showed that spatial updating works in the torsional dimension and operates by rotation rather than shifting.

Adult↗
PubMed2005

Security architecture for health grid using ambient intelligence.

OBJECTIVES: To propose a novel approach of incorporating ambient intelligence in the health grid security architecture. METHODS: Security concerns are severely impeding the grid community effort in spreading its wings in health applications. In this paper, we have proposed a high level approach to incorporate ambient intelligence for health grid security architecture and have argued that this will significantly improve the current state of the grid security paradigm with an enhanced user-friendly environment. We believe that the time is right to shift the onus of traditional security mechanisms onto the new technologies. The incorporation of ambient intelligence in the security architecture of a grid will not only render a security paradigm robust but also provide an attractive vision for the future of computing by bringing the two worlds together. RESULTS: In this article we propose an evolutionary approach of utilizing smart devices for grid security architecture. We argue that such an infrastructure will impart unique features to the existing grid security paradigms by offering fortified and relentless monitoring. This new security architecture will be comprehensive in nature but will not be cumbersome for the users due to its typical characteristics of not prying into their lives and adapting to their needs. CONCLUSIONS: We have identified a new paradigm of the security architecture for a health grid that will not only render a security mechanism robust but will also provide the high levels of user-friendliness. As our approach is a first contribution to this problem, a number of other issues for future research remain open. However, the prospects are fascinating.

Access to Information↗
PubMedDate not supplied

Practical connectivity.

In conclusion, this introduction to connectivity is intended to open up some vision into the possibilities that computer communications offer us. At the same time, some practical hints have been provided that can lead to positive action to take advantage of connectivity, if not immediately, then certainly in our future planning.

Computer Communication Networks↗
PubMed1996

[Why are AIDS patients frequently visually impaired?].

Patients with HIV infection and, above all, patients with full-blown AIDS can get a variety of ocular diseases as well as some cerebral maladies which have an influence on ocular functions. First there are hematogenous opportunistic infections of the retina or the choroid. The cytomegalovirus [CMV] retinitis was found in nearly 20% of all AIDS patients. Without treatment this disease destroys the retina completely, and the involved eye becomes blind. This can be prevented by modern therapeutic strategies in most of the cases. Other infections affecting the retina are toxoplasmosis, systemic varizella zoster or herpes simplex virus infections, syphilis or, seldom, fungal or bacterial pathogens. The choroid mainly can be infested by mycobacteria, cryptococci and pneumocystis carinii. Early detection and treatment of all inflammations are necessary. The anterior eye can be affected by a sicca syndrome and various superficial infections but also noninfectious inflammation. The anterior uvea can be involved in various opportunistic infections of the posterior eye segment. An HIV-associated isolated anterior uveitis has been described in earlier stages of the HIV infection. Treatment of mycobacterial infections with rifabutin can cause an anterior uveitis as well. 1 to 2% of HIV-infected persons suffer from a zoster ophthalmicus with more severe keratitis than it occurs in immunocompetent persons. Last but not least, there are various cerebral affections which can cause visual disturbances. So the optic nerve can be involved in various forms of retinitic or meningoencephalitic processes, of ischemic mechanisms or elevated intracranial pressure. Neuroophthalmological symptoms also include homonymous hemianopsia caused by foci of cerebral toxoplasmosis, progressive multifocal leucencephalopathy or primary intracerebral malignant lymphoma situated in the central neuron of the afferent visual pathway. A variety of oculomotor abnormalities can be caused by a great variety of cerebral disease. Moreover, there are signs of neuroretinal dysfunction in computed perimetry and in color vision or contrast sensitivity testing. Some sight threatening diseases initially can be symptomless for the patient, though they should be treated immediately in order to keep the remaining visual damage small. Thus, regular ophthalmological investigations are necessary in patients with an advanced stage of the immunodeficiency, regardless whether they have ocular complaints or not. Moreover, the patients have to be advised to attend an ophthalmologist immediately, when they notice any kind of visual disturbances or ocular symptoms.

AIDS-Related Opportunistic Infections↗
PubMed1985

Reversible visual loss following optic nerve injury.

A case of shrapnel injury to the optic nerve documented by computed tomography, resulting in total, but partially reversible visual loss, is presented. In view of the visual field defect and computed tomographic findings, a transient vascular insult is incriminated. The irreversible loss in the lower field of vision is related to the shearing effect of trauma on the vulnerable pial vessels supplying the upper half of the nerve.

Adolescent↗
PubMed1998

Multidimensional electrocutaneous stimulation.

Probing the subjective response to a five-parameter electrocutaneous stimulus has revealed a noisy perceptual space. A method for reducing the noise is hypothesized and experimentally tested by comparing the intensity discrimination thresholds along and off the energy gradient. Preliminary results show a reduction of the threshold of up to 60% when stimulating along the gradient. The method is exploited to implement an optimal intensity control in an electrotactile vision-substitution device.

Adult↗
PubMed1992

An experimental system for auditory image representations.

This paper presents an experimental system for the conversion of images into sound patterns. The system was designed to provide auditory image representations within some of the known limitations of the human hearing system, possibly as a step towards the development of a vision substitution device for the blind. The application of an invertible (1-to-1) image-to-sound mapping ensures the preservation of visual information. The system implementation involves a pipelined special purpose computer connected to a standard television camera. The time-multiplexed sound representations, resulting from a real-time image-to-sound conversion, represent images up to a resolution of 64 x 64 pixels with 16 gray-tones per pixel. A novel design and the use of standard components have made for a low-cost portable prototype conversion system having a power dissipation suitable for battery operation. Computerized sampling of the system output and subsequent calculation of the approximate inverse (sound-to-image) mapping provided the first convincing experimental evidence for the preservation of visual information in the sound representations of complicated images. However, the actual resolution obtainable with human perception of these sound representations remains to be evaluated.

Acoustics↗