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Palinopsia with bacterial brain abscess and Noonan syndrome.

Though positive visual symptoms can be psychological in nature, or can result from a perceptive or anxious patients recognizing optical principals in the eye itself, this case illustrates how a thorough history is required to delineate those rarer signs which accompany serious macular or neuro-ophthalmic pathology.

Adult↗
PubMed1976

Eccentric viewing training.

Eccentric viewing training seeks to train subjects to utilize a paramacular area of the retina for seeing when the macular area is damaged. The present paper demonstrates two techniques for training eccentric viewing, as well as a method for measuring impovement in the use of the paramacular area. Both techniques are inexpensive, can be administered by a technician, and do not require an extensive training period. However, there are indications the two techniques are not comparable in effectiveness.

Adult↗
PubMed1999

Does habitual, vigorous optokinetic stimulation alter optokinetic nystagmus and sensitivity to circularvection?

Previous studies have shown that experience with optokinetic stimulation can alter a subject's sensitivity to illusions such as circularvection (CV). The aim of the present experiment was to compare optokinetic nystagmus (OKN), optokinetic afternystagmus (OKAN), and sensitivity to CV between 2 groups of sportspeople: 1) squash players (n = 16), who regularly experience vigorous optokinetic stimulation while engaging in their sporting activity, and 2) weightlifters (n = 16), whose sport does not involve the same degree of optokinetic stimulation as squash, but who nevertheless have to achieve a high degree of physical skill. OKN, OKAN (frequency, slow phase velocity, and timeconstant), and latency to CV (Stage 2 and Stage 3) were measured using electro-oculographic recording inside an optokinetic drum. Contrary to predictions, there were no significant differences in OKN, OKAN, or latency to CV between the 2 groups. These results suggest that 1) the practice effects that alter the sensitivity to CV may decay relatively quickly, and 2) differences in recreational sporting activities between subjects may not be a significant confounding factor in visual-vestibular interaction experiments.

Adolescent↗
PubMed1999

Reduce risk of inducing spatial disorientation using physiologically compatible ground lighting.

Spatial disorientation that occurs while landing aircraft during night operations may result in accidents and fatalities which are often classified as secondary to "pilot error." It has now been determined that the use of "expedient" lights, which include flares, flashlights, automobile headlights, etc., can induce spatial disorientation in pilots. The element that contributes to induction of spatial disorientation is the "point source of light" provided by these lights. Impingement on the retina of concentrated photon emissions, as supplied by incandescent (filament) lamps, flares, etc., produces an "after image," such as occurs when one briefly looks into the sun. The "after image" is caused by the time lag required for reconstitution of the neurohumoral transmitter substances in the retinal rods and cones. Pilots who develop "after images" during the final stage of landing a helicopter at night are predisposed to experiencing spatial disorientation, leading to aircraft mishaps. In contrast to flares or incandescent light sources, cold cathode lamps lack a "point source" of light emission, do not create an "after image," and are ideal to use in night landing operations. Cold cathode lights operating in the range of 512 nm (blue-green) are thought to be the most physiologically efficient color to use for night landing operations. Light sources in this nanometer range provide maximum visibility and safety for the pilot during landing operations under all environmental conditions.

Accidents, Aviation↗
PubMed1976

Iconic memory.

Explore the source record for details and available documents.

Afterimage↗
PubMed2000

The effects of scopolamine and cyclizine on visual-vestibular interaction in humans.

The aim of the present study was to investigate the effects of scopolamine (1.5 mg, transdermal patch) and cyclizine (50 mg tablet), at the doses usually used for the relief of motion sickness, on postural sway, optokinetic nystagmus (OKN) and circularvection (CV) in humans, using a within-subjects, double-blind, placebo-controlled design. Scopolamine and cyclizine were found to have no significant suppressive effect on these aspects of visual-vestibular interaction. Postural sway and CV were not significantly affected by either drug treatment; OKN SPV was significantly increased (p < 0.05), although OKN amplitude and frequency were unaffected. These results suggest that scopolamine and cyclizine, at doses used for the relief of motion sickness, may have minimal suppressive effects on these aspects of visual-vestibular interaction.

Administration, Cutaneous↗
PubMed1975

[Experiences with the treatment of amblyopia with excentric fixation by means of changes of the innervation stimulus of the external eye muscles by means of prismes and operative methods according to Cüppers' principles (author's transl)].

An analysis of 59 cases with excentric fixation shows the special efficacy of treatment methods, which are related to variations of the innervation stimulus with prisme, operative methods and especially with the "Fadenoperation" developed by Cüppers.

Afterimage↗
PubMed1975

[Experiences in the measurements of correspondence using dark red glass and according to image after Cüppers (author's transl)].

The measurement of correspondence using a dark red glass in front of the fixating eye and a foveal after image in the deviating eye according to Cüppers is really an efficient clinical method. In spite of the fact that we are dealing with a dissociating test this method offers these advantages: 1. The objective angle is well known at any time. 2. This method allows a sufficient discrimination in the range of 15 min. of arc. 3. There is a permanent retinal stimulation contrary to the method utilizing after-flash images.--General objections to dissociating tests, for example that given by Goldman, are only limited value, because of the fact that patients with disturbed functions must be differentiated easily from normal persons. Sources of error system mainly from inconcentrated fixation. There is a great demand for attention on the part of the patient. Using this method we have been able to show the 17 cases examined up to now a paradoxical anomaly, demonstrated by a larger subjective angle than the objective angle. Besides that we could prove that lability of correspondence, characteristic for an anomaly, and its alteration depending on which method was used. A paradoxical anomaly was also obtained with other methods such as Hering's after images alone, after image plus real object + Haidinger brushes (synoptophor). From five examples the conditions are presented under which this phenomenon was observed up to the present. The reason of paradoxical anomaly may be seen in the loss of specific ability of cortical cells to localize exactly, especially those cells which are stimulated by foveal area, so that subjective localisation becomes very inexact.

Afterimage↗
PubMed1975

[Cüppers' "Fadenoperation" for complicated eye-muscle disturbances and non-accomodative convergence-excess (author's transl)].

More than ever the "Fadenoperation" according to Cüppers has become an important method to improve the pathological relation between eye position, innervation, and resulting motility. This is achieved by sutural fixation of an over-acting muscle far behind its original insertion. In particular a palsy can be influenced by making a handicap for the contralateral yoke muscle. 40 patients (palsies, nystagmus, strabismus incomitans), who have been treated so far, may demonstrate how the purpose of changing the innervation rather than the length of muscles can be integrated in general therapeutic schemes. The procedure is also helpful in weakening the over-acting int. rectus muscle in strabismus cases with habitual excessive convergence.

Accommodation, Ocular↗
PubMed1975

[Problems on expert classification in cases of traumatic disturbances of ocular motility (author's transl)].

The classification of reduction in ability to earn a livelihood in cases of traumatical disturbances of ocular motility is still mainly based on antiquated values which no longer do justice to the real sensomotor situations. Today new diagnostic methods, most of them developed by Cüppers, give a better and more certain base as to the objectivation of the disturbances and the subjective troubles of the subjet. Moreover, new operative indications and techniques can cure them. Four cases are demonstrated as examples for an equivalent and adequate classification.

Accidents, Traffic↗