摘要:

&NA;Both an increase in convergence and an increase in accommodation result in a decrease in the apparent size of objects of a fixed retinal image size (micropsia). The present study demonstrates that the accommodative micropsia produced by a minus sphere lens is due to the retinal image minification introduced by the lens and to the change in convergence accompanying accommodation. The accommodative act itself apparently does not result directly in micropsia.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;Button pressing response time was measured in five trained subjects to the onset of small visual stimuli imaged across the horizontal retinal meridian at 10° arc intervals from 90° arc right to 90° arc left of the line of sight. Four stimulus luminance conditions were presented at each peripheral retinal location, a low luminance condition (approx. 2.6 ft‐L), a high luminance condition (approx. 22.2 ft‐L), and two conditions in which luminance was varied systematically from low to moderately intense levels from one side of the visual field to the other. The two variable luminance conditions were included to see if it is possible to compensate for the progressive decrease in retinal stimulus image area caused by the apparent pupil. The results indicated that response time to stimuli imaged within approximately 70° arc from the fovea does not differ significantly when all possess about the same luminance. Mean response time is significantly faster to stimuli imaged beyond about 70° arc from the fovea when their luminance is increased by an amount equal to the foveal stimulus luminance multiplied by the cosine of the angle between the peripheral stimuli and the line of sight. These data are discussed in relation to previous psychophysical data and to possible response mechanisms.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;In estimating the amount of aniseikonia that may be present in any given case of anisometropia, it is usual to apply the “rule of thumb” approach. The “rule” states that for each diopter of anisometropia, the amount of aniseikonia to be expected is 1½ to 2 percent. The rule is based upon an average value computed for theoretical amounts of aniseikonia in many possible situations that can occur, some of which have little like‐lihood of being found in everyday clinical practice. Applied to many cases of anisometropia that are common, the rule leads to extreme overestimates and is grossly misleading, often resulting in the mishandling of patients. In this paper, a number of typical cases are dealt with in the refutation of the use of “the rule.”

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;Our eyes and their extraocular motility muscles are a marvelously engineered system for external data gathering. On teleological grounds alone, it would appear that ocular versions and rotations take place, in many cases, along geodesics of least energy and that paths of higher energy are only taken for reasons of binocular near vision. This paper examines ocular versions and rotations from this viewpoint and “explains” Listings' and Donders' laws and also uses a model eye to demonstrate some resulting consequences. Finally, a common misconception about eye movements is laid to rest, and a suggestion made for further laboratory corroboration.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;The relative radiant power and luminous power spectra of the emission from a commercially available green chemical light are reported.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;The customary technique for balancing the refractive (subjective) correction lenses requires the subject to compare the clarity of two images. If there is an inequality in the best acuity attainable for each eye, this technique does not give valid results. An alternate technique is described that does not depend upon maximal acuity for each eye.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;A study, comparing SoflensTMcontact lenses (polymacon) with hard contact lenses and spectacles, and using 150 male and female patients, has been done. Volunteers qualified for the study if they had healthy eyes and had worn one type of corrective lenses for six months before they were interviewed and examined. During each patient's examination, his type of correction was not known. Such matters as visual acuity, corneal measurements and average wearing time were considered. (Soflens contact lenses were felt to be safer than hard contact lenses.)

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

&NA;The evaluation of optometric student performance in learning optometric procedures does not lend itself to standard testing methods. This experiment demonstrates techniques in which video recordings may be used for self evaluation by students learning optometric procedures, as well as teacher evaluation of student performance.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID