摘要:

The effect of sub-fusional intermittency on the appearance of targets of complex spectral composition were observed. Achromatic targets of varying spectral composition, purple targets, and metameric pairs of targets were examined. A daul-beam optical arrangement was used in conjunction with narrow-band interference filters to produce complex targets with known spectral composition. Brightness matches and verbal judgments of hue and saturation change were made with four conditions of intermittency. Results suggest that temporal effects on brightness and color are dependent on the wavelength composition of the target in a simple way.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Haploscopic measurements of the accommodation associated with voluntary vergence were made under normal viewing conditions, after the instillation of a parasympathomimetic drug, and after the instillation of a parasympatholytic drug. The results show that the amplitude of accommodation is increased with the parasympthomimetic drug and is decreased with a minimum amount of parasympatholytic drug suggesting that maximum ciliary muscle contraction is necessary to produce maximum accommodation at any age. They also suggest that the loss of accommodative ability with age isnotdue entirely to a gradually increasing sclerosis of the lens fibers from the periphery to the center of the crystalline lens.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Ophthalmic lenses made from photochromatic Photograytmglass will darken when exposed to sunlight. This paper describes the resultant transmission characteristics of Photograytmlenses when they have been optically coated on the incident surface. Optical coatings of various color densities used for sunglasses have been evaluated. The data suggest guidelines for optometric use of this combination of absorptive materials.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

A vector approach is used in the mathematical analysis of ocular rotations. The basic idea of this approach is to consider unit vectors perpendicular to planes fixed within they eye. From these vectors, the information necessary to describe ocular rotations is extracted. Also some new relationships among the coordinates of the Fick, Helmholtz and Listing systems are obtained.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

A tonometer, which involves no mechanical contact with the eye, has been designed and is being tested. An air pulse generated from the ambient atmosphere with a reliable positive linear force-time ramp inpinges upon the cornea. The pulse causes a gradual curvature reduction, applantion, and finally a slight concavity before the decaying force-time ramp permits restoration. Telecentric optical-electronic monitoring of the corneal vertex specular reflection uniquely identifies, in time, the applanation event.Both human and animal testing have demonstrated a direct linear relationship between intraocular pressure and the time interval to applanation. This permits instantaneous digital readout in mm Hg. An optical-spherometer type system is utilized to effect alignment of the pneumatic and monitoring systems with the cornea in three dimensions. Following alignment and triggering, measurement in the normal range takes approximately 3 milliseconds, does not require lid retraction, and induces only a blink reflex with no discomfort.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Clinical optometric findings on 332 inmates, adult male felons, of a state prison referred to the consulting optometrist for routine services were subjected to statistical evaluation and comparison with data available from nonprison samples. No significant differences between the prison sample and variously available outside adult male samples were apparent in the frequency distribution of attainable acuities, spherical and cylindrical refractive errors, cylindrical axis orientations, lateral and vertical phorias, and the bifocal additions at various age levels. This apparent lack of differences may reflect inadequacies of the comparisons to data not collected or presented in directly comparable manners.A significant frequency distribution difference was found in the interpupillary distances, with mean differences of 0.8 mm, 0.8 mm, and 2.1 mm less in each of three other adult male samples, respectively. No explanation is apparent. A number of statistical observations indicated that a relatively high proportion of inmates had not received or submitted to adequate optometric care prior to that obtained in the prison, that is, they had received significantly less care then comparably aged males who present themselves to public clinics and private practitioners for routine optometric services.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

It is shown both theoretically and experimentally that diffraction effects due to the finite wavelength of light and the limited angular apertures of the lenses employed set a fundamental limit to the precision with which the radii of curvature of small surfaces can be determined optically. Furthermore, attempts to measure the curvature of smaller areas of surface are inevitably accompanied by a greater spread in the individual measurements. In the case of some typical designs of radiuscope and keratometer, this spread corresponds to about 0.2 D in the measurement of corneal power.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Binocular and monocular vision at night were studied with the American Automobile Association Night Sight Meter. Ninety-six subjects were tested for glare vision, night vision and recovery time. No differences exist between monocular and binocular nocturnal visibility. The instrument itself may only be valid as a measure of recovery time from glare.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Marfan's Syndrome, consisting of bilateral dislocation of the lenses, arachnodactyly, cardiovascular abnormalities and dolichocephaly, presents the opportunity of refractively compensating for either the aphakic region of the pupillary aperture or the phakic portion through the dislocated lens. A teen age patient preferred his old spectacle correction in high myopic astigmatic form to all possible combinations of plus or minus spectacles and contact lenses, despite the theoretical and actual improvement in acuity and spatial localization. The only factor the resulted in his accepting the minus power contact lenses to correct the phakic portion of the pupilary aperture was his girl friend's insistence. The case is unique in that contact lenses were designed and worn well in powers ranging from + 14.00 D to −15.50 D by the same patient with no changes in physical design of the contact lenses except for the power.

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0002-9408    

出版商:OVID    

年代:1972

数据来源: OVID