摘要:

A short review of effects on sensory end result from using subfusional intermittent photic stimulation, particularly with part-spectrum inputs. These effects include brightness enhancement with inputs in the region of 500 mμ. In this region and. to a lesser extent in others, temporally induced desaturation may occur. Temporally induced hue changes arc grouped around two neutral points. There is some evidence for supersaturation in some regions of the spectrum. Visual acuity is impoverishable under the same manipulations that produce brightness enhancement but. so far. no marked effect on stercopsis has been demonstrable.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

This paper presents a new way of relating Rushten's findings abcut the bleaching of the pigments in the rods and cones to psychophysical measurements of bright and dark adaptation. This involves a gain control mechanism for controlling the response of the rods, which is a modification of the gain ccntrol proposed by Rushton.Consideration is given to the need for postulating a separate mechanism of adaptation at a level above the photoreceptors. The role played by the positive afterimage and inhibition in the aftereffects of stimulating the eye with light are also discussed.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

This paper discusses the background of nucleation theory with particular reference to photosensitive glasses and detailed focus on photochromic glasses. This includes comprehensive treatment of Photogray(tm) photochromic glass with particular attention on progress since the introduction of BestliteTUglass. Also included is a brief discussion of the application of photochromic glass in the ophthalmic field.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

Previous research by the authors suggests that the perceived brightness of monochromatic test stimuli depends upon the luminance, but not the wavelength, of surrounding areas. This relation implies that light surrounding a flicker test object acts equally on the brightness of any pair of flicker components regardless of the wavelength composition of the surround, and that the flicker luminosity function is therefore independent of surrounding light. The present research examines the effect of annulus wavelength on flicker matches within a concentric disk. The results are compared with those obtained by varying the wavelength of a constant adapting light in the flicker area.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

Each of a group of observers adjusted the intensity of a sun-sized source to his borderline between visual comfort and discomfort (BCD). The measured BCD intensity of each observer was compared with many of his physiological and visual characteristics. Those who complained of glare during daylight automobile driving had a lower BCD intensity which, however, could not be associated with any physiological or visual characteristics. This finding substantiates the concept that discomfort glare is a psychological phenomenon.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

Myopia and corneal curvature changes during a period of weeks after the removal of contact lenses have been analyzed. Group data for more than 100 eyes show a certain agreement between myopia and corneal curvature changes: however, individual data give conflicting results. Lack of agreement occurred frequently and, in some cases, the myopia and corneal curvature changes between test days were in opposite directions and as great as 4.00 D. Myopia changes following the removal of contact lenses cannot be attributed solely to anterior corneal curvature changes.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

The literature relating to the luminous transmission factor of sunglasses is reviewed. Glare, brightness discrimination, night vision sensitivity, visual acuity, reaction time and psychological aspects arc considered, and recommendations are made that sunglass lenses should, in general, have a light transmission within the range 10% to 25%. There appears to be little need for sunglass lenses with transmissions outside this range, even for color-defectives or for persons in occupations such as aviation.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

Under favorable viewing conditions, recognition thresholds have been determined for a Landolt C and five equal area, regular polygons having three, four. five, six, and eight sides. In Part I (Landolt C) there were six observers and 2.168 presentations. In Part II (polygons) there were seven observers and 10.080 presentations. Threshold for the Landolt C was established where the outer diameter subtended a visual angle of 1.93 minutes of arc (visual acuity 2.59). Thresholds for the five polygons were established where the length of a side in each polygon subtended a visual angle between 2.0 and 2.5 minutes of arc.The data indicate a direct proportionality between the reciprocal threshold distances of the five polygons and their number of sides. Furthermore, the data suggest that the discrimination of a regular polygon is a function of the length of its sides. Comparison is attempted between recognition of clinically-used visual acuity targets and regular polygons.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

A patient with undiagnosed hyperthyroidism sought oplometric care because of newly developed diplopia. The patient was referred to her general physician who diagnosed and treated the glandular disorder. The diplopia. apparently caused by a paralysis of the superior rectos muscle not uncommon in hyperthyroidism, created a manifest vertical deviation on straight ahead gaze but not on down gaze. A spectacle correction with tase-down prism was prescribed for distance viewing: a slab-off prism to compensate for the absence of a vertical deviation while doing near work was incorporated.

ISSN:0002-9408    

出版商:OVID    

年代:1969

数据来源: OVID