Adequate Vision Research Articles

Anomalies of disparity detection in the human visual system.

1. Oculomotor and psychophysical depth responses were investigated in thirty individuals by use of briefly exposed disparities in the range from 0-6 to 4-6 degrees (1-8 centrads). 2. The results substantiate a previous finding which reported the common occurrence of specific types of stereoanomalies within a sample from the normal population. However, arguments are presented to suggest that these forms of stereoanomalies are limited to coarse stereopsis and spare mechanisms concerned with fine disparity, high resolution stereopsis. 3. A relatively high proportion of individuals were found to manifest deficiencies of vergence eye movement under these stimulus conditions. These vergence-anomalies are characterized by a marked reduction, or absence, of neither convergent or divergent eye movements to briefly exposed stimuli. 4. The vergence-anomaly is not detrimental under normal seeing conditions since it can be present in persons with adequate binocular vision and normal fine stereopsis. 5. The presence of vergence-anomaly was always associated with the occurrence of stereoanomaly; however, the converse was not true. 6. The results are taken as evidence to show how disparity information is organized prior to its influence upon the processes of coarse stereopsis and vergence initiation.

Marijuana Use by White College Students

Marijuana users are a distinct class, even among drug users. They tend to be more intelligent and come from more affluent and more stable families than users of other drugs do. If these differences are not recognized, certain problems arise when mari juana offenders are sentenced to probation. The failure to de velop a typology of marijuana users precludes adequate super vision and treatment.

MATING BEHAVIOR IN RHAGOLETIS POMONELLA (DIPTERA: TEPHRITIDAE): II. TEMPORAL ORGANIZATION

AbstractComparatively few laboratory-caged apple maggot flies, Rhagoletis pomonella (Walsh), of either sex arrived at the site of assembly for mating (ceresin wax oviposition domes) and no mating pair or ovipositing females were observed until the flies were 7–8 days old. From then on, the level of all three of these activities progressively increased.With respect to the time of day of activity, in the field, assembly of both sexes of flies on the fruit, mating, and oviposition all occurred predominantly during the afternoon on a day when the sun shone brightly throughout the 15-hr daylight period and the ambient temperature was 16 °C at dawn, 24.8° in mid-afternoon, and 17.5° at dusk. Little or no activities of these sorts occurred before mid-morning and toward dusk. In the laboratory, where light intensity was constant at 1000 lux during the 15-hr photophase, the temporal pattern of these activities was the same as in the field when laboratory temperature was programmed to be the same as in the field for the corresponding hour of daylight. However, when laboratory temperature was programmed to be constant at 24.8°, these activities occurred at a high rate throughout the photophase. None of these activities was observed to have been initiated in darkness. It is concluded that sexually mature apple maggot flies may assemble on the fruit, mate, and oviposit whenever temperature is favorable and light intensity is sufficient to permit adequate vision.

Pulpal considerations for operative dentistry

1. 1. Permanent restorative procedures should not be attempted unless the pulp is clinically normal. 2. 2. Maximal dentin thickness or “effective depth” between the wall of the restoration and the pulp offers the best protection for the pulp. This includes the injury that can result from caries, grinding procedures, or filling materials. 3. 3. All burs produce a rise in temperature while cutting enamel and dentin. Temperature elevations can be reduced by the use of burs with small diameters with a light amount of pressure. 4. 4. Handpiece water coolants are necessary in order to keep the pulpal responses minimal when using operating speeds above 50,000 r.p.m. Tooth thickness varies and this is of benefit in minimizing the inflammatory response of the pulp. Cavity extension is the critical phase of cavity preparation in producing a traumatic response. 5. 5. Adequate vision is necessary to produce proper cavity preparations. There is no substitute for the use of the rubber dam to obtain an acceptable operating field. 6. 6. The conservation of the pulp and tooth structure must be realized in all diagnoses and treatments for complete restorative service. No material or technique should serve as a substitute for sound operative procedures.

SCLERAL CONTACT LENSES. THEIR CLINICAL SIGNIFICANCE.

The Need for Scleral Lenses I would not presume to talk about corneal contact lenses here in America. You have a vast experience of their use and are well aware of their limitations as applied to what may be called cases. By this I mean such patients as can see adequately with spectacles but prefer not to wear them. A considerable proportion of prospective corneal contact lens wearers prove unsuitable. Higher degrees of refractive error, particularly astigmatism, present difficulties which are often insuperable. In many cases these lenses have to be worn for a single period during the day, ending preferably with bedtime, because, when the lenses are removed and spectacles put on, spectacle blur makes work difficult or impossible for an hour or more. This is not very important for cosmetic cases but is a serious objection if contact lenses are necessary to give adequate vision. Unless allday

THE VISUAL SUB-SYSTEM CONCEPT AND SPACECRAFT ILLUMINATION.

Adequate vision in spacecraft can be achieved only if specialized attention is given to all elements that influence vision and these elements are integrated into spacecraft design using a systems' engineering approach, here designated “ the visual subsystem concept.” The concept is used here to define general crew station and illumination requirements and illustrates how the requirements are affected by factors such as vibration, acceleration, dark adaptation, visual acuity, and unique environmental conditions. Design parameters are suggested for optimising crew station illumination. Areas that require further research are discussed.

Vision of the aged and cataracts.

The efficiency of almost all ocular functions diminishes with age, but the average person can look forward to adequate vision throughout life. The most common ocular disability of the aged, senile cataract, is readily amenable to treatment. Postoperative vision usually is far better than the level of performance of other physiologic activities.

On the Newness of the New Drama

“Even shapes and colours acquire their meaning only in cultural contexts. The less we know of this context the more we are forced to dream it up.”E. H. GombrichIt is a commonplace truth that irresponsible artists dream up contexts for fictions set in the past, but it is harder to realize that only the best artist, gifted with the Shavian power to “imagine things as they really are” can conjure up an adequate vision of the context of our present lives. Moreover, imaginative concentration on context or situation in the new drama is, paradoxically, a result of a deep wish to restore reverence for human character. This essay will repeatedly address this paradox as we try to isolate our period style. In drama as in other things, not everything is possible in every period.

The use of stereoscopic technique in electron microscopy.

SYNOPSISAn account is given of some of the means by which, using three‐dimensional viewing, effective use can be made of the great depth of focus of the electron microscope. Some modifications in methods of preparation of specimens are mentioned. The main drawback to the method which has been encountered —lack of adequate stereoscopic vision in many people—is briefly discussed.

A useful face mask for endoscopic examinations.

For those persons doing bronchoscopic or laryngoscopic examinations, particularly in cases of tuberculosis, adequate protection has been sought. I have used the item described here for many years with adequate protection and vision. Face mask for endoscopic examinations. It is a face shield used in industry for protection from eye and face hazards. The shield consists of a composition head piece, which is adjustable, and a plastic, transparent face piece measuring 9½ inches (24 cm.) in length and 12⅜ inches (31 cm.) in width. The plastic face piece is removable and easily replaced with snaps and is easily cleaned with water or mercuric oxycyanide (1: 1,000 aqueous solution) but not alcohol. The shield protects the entire face and permits the wearing of glasses without fogging. The face piece may be easily raised or lowered by means of swivel joints which attach it to the head piece. The entire shield with

VISUAL FUNCTIONS IN STREPHOSYMBOLIA

Children who make little or no progress in learning to read during their first two or three years in school quite naturally are often referred to the ophthalmologist, and some of them undoubtedly need corrective lenses. However, many, if not the majority, of them have adequate vision and in reality present neurologic problems. One owes a considerable debt to two English ophthalmologists—Morgan, who described the first case of congenital word blindness in 1896, and Hinschelwood, who published a small monograph on this subject in 1917. In his report Hinschelwood included several cases of acquired word blindness, as well as a group of the congenital type, and emphasized the striking parallelism between them; because of this likeness, he ascribed the occurrence of the syndrome in children to a failure of development of the cerebral cortex in the neighborhood of the angular gyrus. In 1926 I studied several cases of delay in