ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The four components of the model of vision developed by Skeffington are described. The influence of stress induced by reading on the interrelation between accommodation (identification) and convergence (centering) is discussed. The use of a convex lens to reduce the need for adaptive responses is presented.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Several possible models of interactions between accommodation and convergence are compared. Accommodative and fusional vergence effort are predicted for each model using the same set of clinical data. Only one model makes predictions that are consistent with clinical and laboratory observations of fixation disparity. The results support the clinical use of graphical analysis of mutual interactions between accommodation and convergence in the diagnosis of accommodative vergence disorders.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Qualitative and quantitative criteria for prescribing plus lenses at near for prepresbyopes together with 12 behavioral objectives are described. Four quantitative prescription criteria are presented using a combined monocular estimate method-low neutral (MEM-LN) dynamic retinoscopy testing procedure. Each of the four prescription criteria are evaluated relative to an arbitrary +0.50 sphere prescription for seven different observable patterns of accommodative responses at 40 cm. Clinical and research implications of prescribing plus spheres are evaluated relative to the change in proximal stimulus characteristics and the change in accommodative response. Intersystem and intermodal consequences are suggested.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Functional vision problems caused by or associated with nearpoint vision stress include: (1) accommodative disorders (insufficiency, ill-sustained, infacility); (2) abnormal heterophorias (esophoria, high exophoria); and (3) vergence disorders. These vision disorders cause problems with acuity, comfort, and performance (efficiency). A combination of lens prescribing, vision therapy, and work/study visual hygiene recommendations can eliminate or greatly reduce nearpoint stress-induced vision problems.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The prescribing of low-power spherical convex lenses for nearpoint has been advocated on the basis of associated visual and physiological responses. A review of research related to this topic reveals that the physiological effects of plus lenses are highly individualized. The purpose of this paper is to reevalute research on this subject in the context of clinical prescribing.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

This study determines the effective diameter of soft contact lenses for the calculation of their equivalent thickness by relating the physiological response to the wear of prescription and calibration (constant thickness) lenses in a group of subjects. First a relationship is derived between corneal swelling response and thickness of the calibration lenses. Then, by relating the swelling response obtained with the prescription lens to this relationship, it is possible to determine the equivalent thickness of the prescription lens. After determining the geometry of the prescription lenses it is possible to calculate by an iterative integration technique the diameter of the prescription lens to be used in the determination of equivalent thickness. This diameter is found to differ between plus and minus prescription lenses. The integration diameter for all lens powers was found to be 6.7 mm.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The accommodative effects of α- and β-adrenergic stimulation were investigated in human subjects by measuring changes in the response ACA ratio and in the response accommodative amplitude as a result of instilling hydroxyamphetamine hydrobromide and phenylephrine hydrochloride. Statistically significant increases in the ACA ratios were found to result from hydroxyamphetamine hydrobromide, but not from phenylephrine hydrochloride. The accommodative amplitude significantly decreased under the influence of each agent. It was concluded that these adrenergic effects on accommodation were mediated through the β-receptor sites. This provides further evidence of the dual autonomic innervation of accommodation.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

This study attempts to resolve the conflicting reports relative to contrast sensitivity function (CSF) and soft contact lens wear. Contrast sensitivity was measured at six spatial frequencies for 19 subjects (38 eyes) when corrected with either spectacles or soft lenses. Measured amounts of residual astigmatism and/or sphere were corrected using a trial frame and lenses. Additionally, data were evaluated on more than one occasion in order to investigate the effect of time upon visual performance with the lenses. The results indicate a measurable decrease in contrast sensitivity for only the highest of the spatial frequencies tested (22.8 c/deg) when soft lenses were worn. For those eyes demonstrating a clinically significant decrease in contrast sensitivity, responsibility appears to be shared by both the contact lens and the cornea. There were no significant changes in CSF over time.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Some persons perceive an illusion of unequal blackness when viewing two equally black rods in a stereoacuity test. With binocular vision, the blacker rod is usually the nearer of the two. If blackness is used as a cue to nearness, a stereoacuity test can be performed successfully without using stereopsis. Nevertheless, stereoacuity obtained by this means is usually inferior to that obtained with distance judgments. For this reason it is advisable to warn subjects against using a blackness difference as a cue to the nearer rod. Those who saw this illusion binocularly also saw it monocularly. Therefore, it is more than just an artifact of stereopsis. One person observed an illusory difference in rod width as well as blackness.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID