ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Binocular summation, using spatial and temporal modulation sensitivity measurments, has been investigated for human and rhesus monkey observers. In experiments where the refractive errors of both eyes were optimally corrected, the binocular summation functions for both species were similar in magnitude and form, and showed higher summation ratios for temporally modulated stimuli than for spatially modulated stimuli. Monocular retinal image defocus produced a reduction in binocular summation for spatial gratings with the amount of reduction dependent on both the amount of relative defocus and the spatial frequency of the stimulus grating. In contrast, monocular defocus did not effect the magnitude of binocular summation for temporally modulated stimuli for any of the conditions investigated. Overall, the results of these investigations indicate that binocular summation measures of binocular function may have some advantages over other tests of binocular function that could be utilized in the clinical examination of patients.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

In this paper the exact shape of the solutions to the equations for lenses free of oblique astigmatism, as well as those free from curvature of field or peripheral focus error, are presented. These solutions, as expected, resemble the Tscherning ellipses, but strongly deformed.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The effect of conicoid asphericity in one of the surfaces of an ophthalmic lens is examined by means of exact ray tracing. Graphical solutions resembling the Tscherning ellipses are obtained for lenses free of oblique astigmatism as well as for lenses free of peripheral power error or curvature of field.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Based on the fundamental task of the visual system, which is to receive information from the surroundings and to transmit it to the central nervous system, thevisual systemis described as beingemmetropicif the amount of information received through the visual pathways is maximum when the eyes are unaided. A mathematical model of the dependence of the amount of information received through the visual channels on the eye's refractive power and range of clear vision has been worked out. The model, by showing good correlation with common experience, confirms the hypothesis that the amount of information is a coefficient of an eye's approximation to emmetropia and that the criterion of emmetropia of an eye is a particular case of the criterion of emmetropia of the visual system.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Longitudinal data on 559 myopic patients were collected from five optometry practices; adequate adulthood refractive data for analysis (three or more visits after 18 years of age) were available for 108 patients. Patterns of refractive change were evaluated subjectively and by linear regression analysis. Most myopes do not progress in young adulthood (about 20 to 25 years of age). Myopia progression during this age period is more common among males than among females. Adulthood myopia progression is related to an increase in corneal power.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The effect of tinted flexible contact lenses on light sensitivity and photophobic response has often been questioned but never thoroughly investigated. An Alpascope was used to investigate whether tinted hydrogel contact lenses would relieve glare sensitivity in pre-adapted contact lens wearers. Various densities of sky blue and autumn amber Cibasoft hydrogel lenses were used in the study. Analysis of the Alpascope data using thet-test, one-way analysis of variance and Duncan's test snowed that there was no reduction in glare sensitivity when tinted contact lenses were worn.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

A comparison of sector pupil dilation produced with 2.5% phenylephrine and 1.0% tropicamide was carried out on nine subjects. We found that 2.5% phenylephrine produced a significant increase in the vertical as compared to the horizontal diameter at 10, 20, 30, 40, and 50 min after instillation of the drug with the maximum vertical diameter occurring at 40 min. The pupil diameter in the vertical and horizontal meridians before drug instillation was 3.7 mm ± 0.2 (mean ± SE) whereas at 40 min the vertical and horizontal diameters were 6.7 mm ± 0.4 and 5.2 mm ± 0.3, respectively. Instillation of 1% tropicamide produced equal dilation of the vertical and horizontal diameters, which was maximum at 40 min. Before drug instillation, the pupils were 3.7 mm ± 0.2 (mean ± SE) in both the horizontal and vertical meridians. At 50 min the pupil diameter was 7.0 mm ± 0.2 in both meridians in the eye that received tropicamide.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

This paper describes the number, distribution, and characteristics of optometric practices in Nigeria and compares them to similar data in the U.S.A. The results indicate more similarities than differences—the latter attributable to the difference in the age of the profession in the two countries.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID