摘要:

An index to specify the directionality (spread) of Stiles-Crawford function and related retinal photoreceptor directional sensitivity data is proposed. This index, termed the half-sensitivity half-width (or angle) is the displacement in the pupil (or the change of angle of incidence at the retina) which results in a reduction of sensitivity to one-half that at the function maximum (0.3 log unit decrease). The half-sensitivity half-width or angle, unlike other currently used indices of retinal directionality, can be assessed empirically and is not intrinsically dependent upon curve-fitting assumptions or procedures.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Designing size lenses for aniseikonia correction usually involves considering only the shape factor of the total spectacle magnification. However, for minus prescriptions, an increase in the shape magnification of a lens does not always result in total lens magnification. As the front curve of a lens is steepened (which increases the shape magnification), the sagittal depth of the lens is increased, which effectively increases the vertex distance. For a minus lens, an increased vertex distance means decreased power magnification; depending upon the lens power, the decrease in power magnification can totally offset the increase in shape magnification. The shape factor-power factor relationship of high minus size lenses is presented, along with general guidelines for proper design of size lenses.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Stereoscopic tests of 30 subjects by means of diastereo instruments showed a lower threshold for crossed disparities than for uncrossed disparities. These findings support Richards' conclusion that crossed and uncrossed disparity limits are the result of two different mechanisms.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

This is a report of the application of contact lenses for prolonged wear by military pilots. The safety and effectiveness of wearing these non-HEMA hydrophilic lenses in a highly demanding visual environment is described in the case of an individual jet-fighter pilot who has worn these lenses continuously for 3 years without any complications.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID