摘要:

Thickness changes in the epithelium and stroma of the cornea of a living rabbit eye were observed with the specular microscope. Previous experiments on the excised cornea using this technique have failed to show any thickening of the corneal epithelium due to anoxia at the anterior surface. In the living eye, the same result was obtained. The results confirm that corneal edema due to anoxia is caused almost entirely by swelling of the stroma, the epithelium undergoing very little thickness change.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The effects of 12 days of continuous monocular occlusion on the stereoscopic acuity and the magnitude of the fixation disparity associated with a given amount of prism-forced vergence were investigated in six adult subjects with normal binocular vision. After the period of occlusion, all six subjects were able to perceive Stereopsis, although four of the six subjects demonstrated a slight but reversible elevation in stereothresholds. The general shape of the fixation disparity curve for a given individual was not altered by occlusion, but changes in the magnitude of the fixation disparity were observed for some subjects.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A simple and rapid method for assessing the visual acuity of infants can be a valuable tool for eye care specialists as well as for researchers in vision. We have developed a preferential looking (PL) procedure that uses simple equipment to obtain measures of PL acuity in a few minutes. Infants ranging in age from 2 weeks to 1 year can be tested. Sessions on infants without any visual problems are completed in less than 5 min. Computer simulations of the technique show that the fast procedure attains almost 80% accuracy in assessing infants' PL acuity thresholds. When PL acuity thresholds obtained by the 60-trial method of constant stimuli were compared to those obtained by the fast method on the same infants, they were identical on 70% of the sessions and only off by one-half octave in an additional 20% of the sessions. Interobserver reliability was also high. The ease and rapidity of the procedure make it appropriate for use in the clinic.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The fast preferential looking procedure was used to obtain measures of acuity in a group of infants without visual problems whose ages spanned the 1 st year of life. The results show an increase in acuity on horizontal and vertical square wave gratings from about 6/360 Snellen at 4 weeks of age to about 6/18 at 1 year. Acuity on obliquely oriented gratings (045) increases more slowly so that by 1 year of age it is only 6/36.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Ives found that when monochromatic stimuli are matched to white by flicker photometry, they are not equal in brightness to the white by direct comparison, and the discrepancy is minimal for yellow but is increased for longer and shorter wavelengths. On the two sides of yellow, the colors are more saturated, and Ives postulated that brightness involves the sum of a chromatic component and an achromatic component and that the chromatic component varies with the saturation. In the case of a deuteranope, one would expect a vigorous chromatic response for yellow and blue stimuli but a poor response for the neutral part of the spectrum. The Ives effect is virtually nonexistent for subject SR, who is a deuteranope. In terms of the zone theory of color vision, this would mean that the blue-yellow chromatic channel contributes little or nothing to brightness. In a normal observer, the blue-yellow mechanism can be isolated by using blues and yellows depurified with white, but in this case the Ives effect is found to exist.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

An optometer (infrared recording retinoscope) was used to monitor the accommodation of subjects (N = 40, ages 20 to 30 years) to determine whether an increase in cognitive demand would result in an increase in the level of their accommodation. When the subjects in the experimental group (N = 20) changed from reading 2-digit numbers at 40 cm to adding the numbers, with no change in the visual stimulus, the average level of accommodation increased in 75% of the subjects—the mean level of accommodation increased 0.28 D (P < 0.01). Subjects in the control group (N = 20) showed no significant change in accommodation. The increase in accommodation is attributed to an increase in cognitive demand.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A questionnaire was developed to measure changes in certain behaviors at various intervals after correction of refractive errors in a sample of mentally retarded persons. The sample comprised three age groups: 0 to 6 years, 7 to 1 7, and 18 and above. In each age group, four subgroups were selected—one experimental (new-glasses) group and three control groups. In the group which received new spectacles, changes were recorded in social behaviors, gross and fine motor skills, and reading and writing skills. These changes were most evident in the youngest age group.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A case of bilateral inferior conus is reported; relative scotomas were found to be congruent with the location of the conus. Existing theories, proposed to account for scotomas associated with inferior conus, are discussed. A new theory is proposed.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID